F650 Aftermarket Forks

Original FAQs by Kristian #562, BradG #1002, Scott ID #1244
Please read the Disclaimer before attempting any work in this FAQ.
Last Updated: 3 September 2006, by Winter #1935

For FAQs related to forks, shocks, maintenance and aftermarket options:


There are lots of options for aftermarket fork protectors. Here's a few different types, with some comments on each. You may not see some of the advantages or disadvantages as particularly troublesome. It's your bike, so you choose. This is just to give you an idea what's out there, and what the people who have them, who have said something about them, have said... Information on complete aftermarket forks is a little harder to come by - please let us know if you have more information to help fill in the blanks!

Fork and Spring details (based on the Classic F)

What are emulators?

Think of the emulators as restrictor check valves that help control the oil flow inside of your forks. The damping action comes from forcing oil through a restriction. I guess they wok. My bike's PO put these (gold) emulators in with stiffer springs. I added some higher grade (SAE 10W-40) fork oil last seal replacement. They work alright together. Nothing I would enter competition with, though. I do not know how much they cost. beem_dubya #1328

From the Race Tech website (thanks beem_dubya #1328)

Race Tech Emulators enable damping rod (conventional) forks to duplicate the fork action of well-tuned cartridge forks. Standard damping rod fork setup is a big compromise. They have either mushy fork action under braking and going through dips and gullies or harsh fork action while hitting square-edge bumps. In addition to the vehicle speed, the size and shape of the bump are critical factors. This poor fork action is because damping rod forks create damping by simply shoving oil through holes. At low vertical wheel speeds the holes do not have much resistance to the flow and therefore are mushy. As the velocity of the fork increases the resistance to flow increases dramatically and more oil cannot be forced through the holes. This is what makes them harsh.

Emulators were invented by Paul Thede in 1993 and are variable orifice valves that sit on top of the damping rods. Not only do they create a firm yet plush ride with excellent bottoming resistance they also provide the ability to adjust compression damping. Thus, with Race Tech Emulators installed, conventional damping rod forks are turned into forks with excellent well-tuned cartridge fork type action.

Aftermarket Fork Options

Heavier Fork Oil

Probably the low cost / easy option is to use heavier fork oil. See the Fork Maintenance FAQ for more information on changing the fork oil. Try a 10wt oil, or may be even heavier. If you ride a lot of dirt, particularly at higher speeds, or you carry heavier loads on your bike you might consider even as high as 15wt.

Touratech Upgrades


Touratech offers several upgrade options for the F650 GS models. The most extensive upgrade is to WP forks and shocks with a huge 280mm and 250mm of travel (respectively). This upgrade includes all parts to perform the upgrade. However the kit is expensive - but includes everything you need including the bracket for the ABS sensor (if you have ABS). Touratech also sells fork springs for the Funduro and GS. (Note: In the closeup image below, there is an additional reed sensor for a bike computer. The Touratech 650RR instructions have more images of the kit installed).

Touratech upgrade (taken from Max Kool on advrider)

Closeup of ABS sensor (taken from somewhere?)
Is this an earlier version???

How much higher is the Touratech WP setup?

The upgrade takes to front fork travel to 280mm and rear shock travel to 250mm. This is compared to about 170mm on the GS and 210mm on the Dakar. In other words an extra 40mm (nearly 2in) of travel on the Dakar and a huge 80mm (just over 3in) on the GS.

What are the exact model and specs of the WP fork upgrade?

The forks are the WP 4357 MXMA USD 280mm. The shock is a 4014 Fusion with 250mm travel. You can also get an axle and brembo bracket from WP suppliers, and also upper and lower clamps.

What are the part numbers for the Touratech upgrade?

The following table contains the Touratech part numbers for the WP USD 250mm upgrade. The first group are the components you will need. The other groups you may or may not need depending on if you can source the other parts from elsewhere. (Please check these part numbers!)

Part No Number Description
05-320-0180-01Upper fork mount
05-320-0181-01Lower fork mount
05-320-0182-01Center steer tube
05-320-0184-01Ignition switch mounting bracket
05-320-0185-01Front brake caliper mounting bracket
05-320-0186-01Front axle
05-320-0188-01Roller bearing ??
05-320-0189-01Bearing race???
01-300-0188-01Nut for front axle
05-320-0210-01Sensor mount (front wheel)
05-320-0211-01Sensor cover (front wheel)
You Could Source These Elsewhere
05-320-0170-01Front forks WP 43mm USD (250mm or 280mm travel)
01-040-0800-01 pairFront fork protectors
11-112-0904-06Spacers for fork protectors 10/6/4mm
Bar Rises - Purchase as required
05-320-0183-02Bar mounts
05-310-0190-02Top handlebar clamps
05-310-0191-02Lower handlebar clamps/risers
05-310-0182-02Steering stops
01-040-0335-01Front brake line Stainless steel

Touratech Fork Clamps

Touratech Front Axle

Touratech ABS Mount, Spacer and Caliper Bracket

Using KTM WP Suspension

Thanks to atgreg over on advrider: It's not my bike but a friend of friend, the forks are 50mm whitepower extremes from a 99 KTM. Triple clamps are custom made, extending the rear swingarm means you get more suspension travel for the same length of shock. This bike will have a longer WP rear shock as well as the extended swingarm and will have close to 300mm of travel at each end.

1995 Honda XR250 Upgrade

Hi i just want tp share the installation af a cartridge type front fork on a f650gs 2002, the newfork came fron a XR 250 1995 all fit,41mm fork wheel and brake line. Roberto

CBR600F2 Forks in a Funduro

I dunno about the fool infected bikes. But a set of CBR600F2 forks will slip right into the clamps of a Funduro. Flash #412

Cytech Air Suspension Upgrade

See the http://www.toursforafrica.co.za/ website for more details. Has anyone actually done this mod? Feedback would be fantastic! According to the website you must also use bar risers.

Marzocchi USD Forks

The following appear on http://victoria.craigslist.org/mcy/138985865.html... It is a custom mod of a F650GS (possibly with ABS). The following is what was listed, including the use of Marzocchi USD Forks. No specs or details were provided:

2001 BMW F 650 GS
10.900 K km's
Steel blue metallic
Custom build and re-desiged BMW 650 GS
17" BEHR 3.50 x 17 polished front wheel with racing tire
320mm Front Rotor
Tokico 6 piston caliper
New 2005 Marzocchi upside down front fork
Pro taper triple clamps ( 6 bolts )
Pro taper handlebar positioners changers
Pro taper Ricky Carmichael 2005 handle bars 1 "tapered
ABS on both wheels
Heated grips
Custom seat
Upholstered front fairing
and more

Preload Adjusters for Front Forks

11/4/99, Peter #233

With the nifty preload adjuster for the rear shock, wouldn't it be nice to have the same feature on the front forks. figured out that the 91 Honda CBR 600 F2 has the same diameter of tube as our F650 and it fits.

Since Honda is the parent company of Showa why wouldn't it. The Honda part # is 51450-MR8-003. Peter's local dealer charged about $45.00 ea. It requires changing the spacer and clip on the bottom (Peter guessed that the BMW has thicker castings than the Honda). Replace the spacer with 2 1-1/4" fender washers and a smaller cotter pin. They'll fit perfect after that little mod, and you will be able to dial in the preload on the front suspension. EBay occasionally has pairs listed for Honda CBR600 F2/NT 650.

Q. The FAQ talks about using '91 CBR 600 F2 adjusters. Anyone have any idea if '94 CBR 600 F2 adjusters will work? '97 F650, #1291.
A. Yeah, F2 are the same. Pro'lly a whole bunch of other Honda models with 41 mm forks. Harl #380 '98 KLR 650, ex F650. Fort Collins, CO.

Race Tech Gold Valve Emulator Install

by David #476
Photos by Iceman #975 and Harl #380


To go along with my new Ohlins Rear Shock, installed a pair of Race Tech Gold Valve Emulators, Race Tech Springs, and Honda F2 Pre-load adjustors on my fork.

Tools required:

Removing the Stock Forks and Springs:

  1. The install is very simple and required very few tools. The BMW manual suggests removing the entire front of the bike to do this, but I knew my Steering Head Bearings were good, so I thought that removing the Gas Tank, Fairing and Triple Tree was just needless work. If you have any doubts about yours, you may as well take it all apart and replace the bearings.

  2. First thing was to lift the bike. I bought a motorcycle jack that worked dandy. Available at Costco for $100, it's something I've wanted for quite some time, and this was the perfect rationalization to buy it. It took a couple of tries to get just the right lift, until I found a two by four under the skid plate and the two center stand mounts lifted the bike perfectly straight. I used tie downs to the rear rack and jack and it was extremely stable, allowing me to move the bike around to deal with the limited space I had to work on it, which would have been a problem with the front end removed. That said, I'm sure you could do the job on the center stand if you wanted.

  3. Then I removed the plastic from the front wheel; the fender and the caliper cover. Then the caliper itself. I made a hook from a clothes hanger bent in the shape of a 'C' and hung the caliper from the plastic radiator surround. This keeps it out of your, as well as harms, way. Next was the front tire. Loosen the four bolts on the axle keeper (no need to remove them) and unscrew the axle with the 12 mm Allen wrench Then I removed the fork brace/Fender support.

  4. At this point you have the bike suspended in the air with everything removed from the forks, which are now ready to be removed themselves. As stated previously, the manual says the fairing and gas tank (as well as the handlebars on an ST) should be removed, but I found this unnecessary. By simply moving the forks left and right, I was able to get my ratchet in to undo the bolts.

  5. First I loosened the top bolt on each triple clamp, (marked yellow) then I undid the fork cap, taking care to keep the spring pre-load from shooting the cap across the room. You don't need to worry to much about this as there is hardly any pre-load on the stock forks. (More about this later) A word of caution here. The fork caps are aluminum with extremely fine threads. The forks are steel, with a spring pushing up on the cap. In order to keep from damaging the threads, especially the last two or three, it's important to keep downward pressure on the cap as it's unscrewed. I found a closed end wrench worked best for this, keeping downward pressure on the cap with my finger while I re-set the wrench. Remember, you should be able to loosen and tighten this cap by hand once the torque is broken. If it won't, there's a good chance it's cross-threaded, so be careful. Doing it by hand also gives you good feedback on the amount of downward pressure you using.

  6. Once the caps are out, you can remove the spacer, washer, and spring from the fork. Then it's time to drain the forks. Get a container ready and open the 10mm bolt on the back of each fork. The first little bit comes out at a good rate so be careful. (I found a supply of oil absorbent close at hand was invaluable for this entire job, BTW). Let it drip for a while, it will save you cleaning up a mess later on as quite a bit is still in there when it stops flowing. At this point, put the axle back in to keep the forks from turning and break the bolts in the bottom of each fork leg, which hold the damping rods in place. Leave them is place, just finger tight for now. Now take the axle back out and remove the forks by undoing the two Allen head bolts on the lower triple clamp and carefully sliding the forks out the bottom.

Modification Work:

  1. From here the damping rod needs to be removed for drilling. While it is possible, so I'm told, to do this without disassembling the forks. I chose to take them apart so that I could clean them, inspect the bushings and replace the seals. This is accomplished by finally removing the bolts from the bottom of the forks and turning them upside down. The damping rod and top out spring should fall out. Then carefully place the lower part of the fork (outer tube) in a vice, and using the upper part (inner tube) as a slide hammer to pull the seal out. In the very bottom of the fork is a cup which goes between the damping rod and the outer tube which is very important. If you elect not to completely disassemble your forks, its necessary to get this cup in correctly on reassembly. At this point I would lay out all the parts and compare them with an exploded picture of the forks from the manual or parts book, so that you know you have everything and you know where everything goes. This mental picture will help you later on, when putting it all back together.

  2. Next I would take some time for a religious cleaning of all the parts. For the chrome fork tubes carb cleaner and a well worn ScotchBrite pad work well. Interior of the outer tube I used carb cleaner and a Heavy Duty paper towel, but a cotton cloth would work well too.

  3. Now it's time to drill the damping rod. The instruction say at least 6 5/16" holes. The rod comes with two, so I drilled these all the way through and added a pair above them. Thoroughly de-burr these holes inside and out. You don't wan a bit coming loose and landing in your seal down the road. Then re-clean them.

  4. Next, set up the emulator (top view). Here's a view of it from the bottom and side. I found the instructions a little unclear here, but several calls to Race Tech cleared things up. As they come from Race Tech, the emulators are not adjusted. To do this you back the adjustment bolt off until there is no pressure on the spring. (Kinda like a feeler gauge feel thing) Then screw the bolt in the desired amount of turns. The instructions say two turns. A call to verify this was for off-road (I bought a set for my Triumph which also said two turns so I called) revealed an error. The recommended setting for off road travel is one turn. To make a long story short, after installing, un-installing, re-adjusting, and re installing a couple of times, I finally settled on 2.5 turns, but I'm a heavy guy and I often travel well loaded (with luggage, that is!) Also, this is totally subjective. One turn is soft, but in a different, more controlled way than stock. Four turns is great, highway driving is sweet and off road the bike tracks like it's on rails. The only problem is that it's stiff. Unless you're a body builder who runs marathons or Ricky Carmichael, it will wear you out quickly and isn't much fun after about an hour. Here's a view of the emulator in place on the damper rod.

  5. Next, you need to make the spacer. If you were using the stock spring and wanted to retain stock pre-load, you would need only to remove 20mm off of the stock spacer to compensate for the height of the Emulator. Another member of the Chain Gang, wanting to add pre-load to the front end, simply put the stock pre-load spacer in as is. The Race Tech spring I got was 100mm shorter than stock, but thicker (hence stiffer) so some math was involved. This was complicated by the fact that I was adding the additional length of the Honda Pre-load adjustor (12mm fully out) as well. Here's how it worked out: The stock spacer (100mm)and washer (1.5mm) added up to 101.5mm. My shorter spring meant I needed to add 100mm minus the 20mm for the Emulator and 12mm for the Honda pre-load adjustor. Based on the fact that there is very little stock pre-load, I decided to add 5mm as well. So;101.5+100+5-20-12= 174.5mm. I figured what the heck and made the spacer 175mm. This is accomplished with a large size pipe cutter available at any hardware store. Once again, this tube needs to be thoroughly de-burred.


  1. Now it's time to re-assemble. I placed the damper rod cup into the (immaculately clean) outer tube, the spring over the (equally immaculately clean and be-burred) damper tube and dropped the pair down the (immacul... you get the idea) inner tube. Then the inner tube goes into the outer tube and with the damper rod fixing bolt on the end of an Allen wrench (T-Handles work the best) fiddle about until you get the threads started and tighten it down. Don't worry about the torque at this point but remember it's only 25nm so don't make it too tight. Next open your brand new 10wt fork oil bottle and put a little on the top bushing as well as splash a little bit down the outer tube. (Oh yea, don't forget to replace the drain plug first, DOH!) Squeeze the bushing lightly and get it started down the outer tube. Now it's time for a special tool. You can get one at any M/C shop for $40-$50 or do what I did, get 1 1/2" PVC pipe coupler and grind the center stop out of the ID. This fits over the 41 mm inner tube perfectly. Then I simply tapped gently with a hammer until the bush is in. For the last little bit put the washer into the tube as well. When the washer has bottomed out you know the bushing is in as far as it will go. Next lube up the INSIDE of the seal with good ole #10. If you get any on the outside wipe it off and slide it down over the inner tube. Make sure the writing on the seal is up and you can see the spring. (another DOH!) Then I placed fork seal tool on top of the seal and tapped gently again until the seal bottomed against the washer. Next I lubed up the dust cover and pressed it down over the top of the seal.

  2. Next is fork oil. The Race Tech spec is 120 mm down from the top of the COMPRESSED fork, with the Emulator in, but the spring, spacer and washer out. This ends up being about 50cc less than the 600cc recommended by the factory, but measure it with a rule, not by volume (a hook rule, available at Sears, works great for this). Note here: Put about 300 cc in and work the fork up and down to expel all the air from the bottom of the fork, (Another DOH) do the same to the second fork, then go back to the first one and do it again. Then put the remaining oil in and measure. If you get too much in, a turkey baster works great to remove a little bit.

  3. Once the oil level was set, it was ready to button up. First thing, extend the fork all the way and make sure all the flowing oil hasn't pushed the Emulator out of place. Put the spring in, followed by the washer, then the spacer. Note here, The spacer needs to have a washer between it and the spring and between it and the cap, if you're not adding the pre-load adjustor, you'll need to use the two washers that come with the Race Tech spring (and grind them a little bit, 'cause they're too big to fit!) and adjust the length of the spacer accordingly (The R-T washers are 2mm as opposed to 1.5 and you need 2= 4mm instead of 1.5) The bottom of the pre-load adjuster is actually a washer, so if you're doing this as well you won't need a washer in between the spring and the adjuster. (Although you will need to grind it as well. Once again a little to large for the inner tube.) At this point fully extend the fork and make sure you only have 20-30mm of spacer sticking out the top. Any more (or any less) means something is wrong. Most likely the Emulator has been dislodged by the fork oil. If so remove the spacer, washer and spring and move the inner tube up and down a little until the Emulator gets back in place.

  4. Now for the cap. The cap should be put on in the "fully retracted" setting. As stated earlier the cap is very delicate and needs extreme care. Holding the inner tube in one hand, I let the fork fully extend. With the other hand I pushed the cap down on the spring to get the threads started. Gently pushing down on the cap as you turn, the cap should go on all the way to the o-ring by hand with no problem. If it doesn't , chances are it's cross threaded. Take it off and start over. Once you get to the o-ring tighten it down. (Save the torqueing for later). Here's a picture of the Cap fully extended and fully retracted.

  5. With both forks done, it was time to put them back in the bike. A note here. Unless you have a lowered bike, when you disassembled your forks the top of the cap was even with top of the top triple clamp. This spec has been changed. The top of the INNER TUBE should protrude 3mm above the top of the triple clamp. At this point I just tightened the two Allen bolts on the lower triple clamp, just enough to keep the fork in place and torque the fork cap and the damping rod keeper bolt. Next I put the fork brace on, then the wheel. Torqued the axle bolt, leaving the pinch bolts just finger tight. Then the top fork pinch bolts, getting the bike off its stand or jack and, I sat on it and compressed the forks several times. This lines up the forks and axle. Then I torqued the lower fork bolts and the axle pinch bolts, then undid and re-torqued the top fork bolts.

  6. Now all that was left was to replace the caliper, caliper cover and the fender. And ride.

  7. I would suggest a short test ride staying close to home, checking for any untoward noises and vibrations. Once your finished, park on the center stand, check all your work, make sure everything got torqued and tightened properly and you're done.

Here are some further Photos from Harl #380: Emulator pre installation, Emulator on Rod, Emulator, Rod showing Drilled Holes

Riding Impressions:

The shock and fork transformed the bike. Now the bike stays planted as if it weighed 100 more pounds, but it is every bit as flickable as before. When turned into a corner, in maintains its line much better. When passing or being passed by large trucks, the turbulence barely affects the bike. In crosswinds the bike goes when you point it, rather than wandering all over the place. The overall effect of the mods is that the suspension is stiffer, but at the same time, it reacts faster and better to input. And best of all, it's adjustable.

I'm still in the process of experimenting, (and this process could last a long time!) but the ability to change the suspension for Road and Off-Road, Load or no Load is fantastic. With the exception of the Emulator, a change takes only a few seconds by the side of the road. While my first few adjustments of the Emulator required draining the fork oil and removing the fork caps, (I did it the last time in 35 minutes!) I don't think I'll have to do it again soon, the Honda pre-load adjuster allows a lot of adjustment. All in all, a great investment in riding and traveling pleasure.

AK-20 Cartridges

Here's the the response to my e-mail from Mike Hardy at Traxxion Dynamic.

"Yes, we can certainly make the AK-20 fit. I am almost positive the our Damper Rod Kit will drop in as well. So either way you want to go we will be more then happy to accommodate you. Send the forks in we will hook you up."

So it looks like I will be sending them my forks after I get back from the rally in June. I can't wait to have the AK-20's installed along with the Ohlin's shock. This bike should ride like a dream.

Spring Options

Aftermarket spring options include:

Here are some comments from members using various springs.

In general terms you select spring rates (stiffness) based on two basic criteria. First, the weight of the bike, rider and normal load. Second, for the type of riding you do. The more weight the stiffer the spring will need to be. The other factor is where you ride. Street riders use and need stiffer springs than off road riders. When off road the suspension needs to respond to a greater range of motion (the bumps are bigger and more numerous). However, be careful about using spring rates that are common for the typical off road motorcycle like a motocross machine. These are much lighter than our dual sport machines. That is why weight must be included in the decision as to what rate springs to use.

It has been reported by others that the stock springs in the F are about a .6 rating. This may be suitable for you. For some, usually heavier riders (180+ pounds), they are too soft for street use and may even be too soft for off road for those carrying more than 200 pounds. In the end, the choice is a compromise if plan to use the F as a true dual sport. Like tires, you can't have the best of both in one solution.

Don't forget that spring rates are related to fork oil weight. The weight of the fork oil needs to be matched to the springs you choose. There are as many opinions as options on this topic. Keep in mind that the stock front suspension on the F has no adjustment for either compression or rebound damping (thus the interest in Gold Valves). The weight of the fork oil in a stock setup is going to have more of an affect on rebound than compression. The stock oil is 7.5 weight. Some members report good results with 10 weight oil when using stiffer than stock springs. For off road applications it would be unusual to need higher than 10 weight (oil that is too thick will slow rebound so much that the front wheel will not return quickly enough).

Lastly, the quantity of oil plays a role as well. The simple explanation is that changing the oil level changes the amount of air in the fork. Air compression plays a part. The less air the more resistance to compression. More information in the Fork Oil Change FAQ on fork oil.

If you are curious enough to want to know the 'spring rate' of your springs you can learn how to calculate it by reading the Spring Rate FAQ.

Comments on Diving Under Braking/Spring Installation

Touratech's Progressive front springs Installations

TT spring installation

I'm received the TT Dakar springs yesterday and will try to install them tomorrow. Feel a bit unsure about it and since I'm going away on a 1 week offroad tour this satuday I don't want to mess anything up. Checked the faq but found no description, probably because it's so simple, but I like to make sure anyway.

To install the springs, do I just remove to caps (and screw) on top of the fork legs, pull the old springs out and replace them with TT springs? My plan is to start with replacing the springs and then maybe later change the fork oil. bjorna

Scott, ID #1244: That's about it! However, they do recommend a different oil level; if the oil looks dirty, you may as well change it at the same time.

Oil Level With Progressive Springs

I just installed a couple of Touratech's progressive springs. Does anyone know how much oil I must remove from the fork legs for them to work properly? If no one does, can you come up with a method of determining this accurately? What are the potential problems I might face by running the bike with too much oil in the forks? Mexico Juan. Actually they do displace a significant amount, I think. Not only is the wire thicker, but it has more coils!!! Balam

Conclusion on oil level with progressive springs:

Over the past few months it has been posted a few times that the use of progressive springs in the front forks should be done with reduced oil levels from stock. Here is what I found after running Touratech springs in my standard GS in both states.

  1. with stock oil levels - very firm ride, so much so I reduced pre load to a minimum to compensate. It was acceptable on the street but too harsh off road.
  2. reduced oil by 50 cc a side - I retained the short pre load spacers. The ride is much improved off road. I'm convinced now this is the correct approach with these springs. There is a bit more dive under braking on the street but still way better than stock.

Side by side with the OEM springs the Touratech are clearly going to displace more oil when installed. The exact amount I never bothered to try and calculate. Now I'm wondering which is the correct way to install these springs. Should the tightest coil portion be on the top or the bottom? This would affect the displacement of oil some but I can't imagine it would affect performance otherwise. The air column size is what is key. I'll make a dipstick from a coat hanger and measure oil level on the center stand with no load on the front wheel. Always good to start from a known and adjust from there. BradG, N. CA., 2001 F650GS - Inmate #1002


Aftermarket Triple Tree

by beem_dubya #1328

I installed a custom triple clamp on my Dakar. Replaces the stock set perfectly, switches, bar height, ignition, fork lock, etc. Anyone with an '01 or newer GS should see my pics. Anodized blue, two top clamp bolts per side, vibration isolated bar risers, mount for the BMW power plug next to the ignition switch, SWEET. You can get the bar risers in several heights, sized for stock or aftermarket bars (Pro-tapers, etc) and the whole thing can be done in several colors.

Why do we modify our bikes at all? To make it better. (if only in our own minds) I installed it because the first one I had seen (on the counter at Engle's) it seemed cool. Then after riding out to Emig Racing and meeting with Gary, it seemed to be a sensible mod. Stronger, adjustable bar heights, power plug in a more accessible area for my GPS, etc. Gary had made the prototype for his Dakar, shown me the bike and then we talked at length about it. We talked about why he made it, how it rode, strength, etc. Gary is very experienced both in dirt riding and machining which leads me to trust his ideas. I loved it and thought it was a great idea. I am going to do suspension upgrades but am still in the research process. (WP, Ohlins, etc) Then there is the custom factor. Nobody else has one and it sets my bike apart. Gary of course has one (silver) and he has sold others, but as of now, this is the only one made public. (as far as I can tell) It's different.

So how weatherproof is that cap on the end of the power plug? And if water gets in there, does it drain out through the bottom? I had the exact question for the the manufacturer, Gary Emig. He reported no problems to date and neither have I. He rides an 02 Dakar, KTM LC4 and others with the same set-up. I rode to a local BMW club meeting the other day in 38 degree pouring rain and had no problems. I'll report any long term successes and/or failures.

For anyone interested, the website is: www.emigracing.com


Adding Preload Spacers

by Marty #436-Chicago-97 F650F

On the old Airheads, front end "dive" under braking was also an indication that the rear shocks were going (actually, the front end wasn't really diving, the REAR end was rising due to weak shocks/springs). That said, I added the +50ml/leg (of 10wt) oil to the fork legs (Classic...this is allowed for the lowering kit, so it should be OK for stock), plus fabricated new preload spacers 1/2" - 3/4" longer (13-19mm for you metric folks) from PVC tubing. Front end doesn't dive any more, but it feels pretty stiff. I may put the original spacers back in at the next fork oil change.

To stiffen up "the front wheel", fabricate some slightly longer preload spacers for the front forks. Cheap fix. I'm assuming that 95 and 97 forks are similar or identical.

The preload spacers are thin walled pipe (think car exhaust pipe, but smaller diameter). Pretty hard to stack two of them end to end inside the fork and expect them to stay. Maybe better to use a stack of washers, but stay away from plated ones (the plating could flake off and do bad things to the dampers?). PVC pipe seems to be working OK, and is cheap.

When getting your PVC make sure you get the thicker wall pipe. In the US we have two types. One thin and one thick. The wall should be about 3mm thick. Given that all the parts will be coated in oil you can probably use stainless steel washers. The plated washers are usually plated with zinc.

As BG mentioned, the plating is usually zinc (galvanized) or similar to prevent corrosion. He's right on about getting the thicker walled PVC. You could also use hollow metal closet rod (idea from another inmate) if you can find the right size (and again, be aware of plating, probably "chrome" in this case). Be sure that you clean up well whatever parts you put in there after cutting, you don't want any metal or PVC "sawdust" in your hydraulic forks!

Reducing Fork Tube Torsion during Spring Compression

Draft FAQ. Not Ready for Prime Time "Just Yet"
Harl #380, Fort Collins, CO.

This was posted on another site I frequent.

A coil spring by design is a torsion spring; however, due its wound-up design, a coil spring wants to rotate one end when compressing and expanding. While not a big problem on cars, since the coils are short and rigid, on a motorcycle the coil spring action is noticeably crippled by the amount of friction the spring has to overcome to turn.

On many bikes that forces the spring to bend sideways, and if not possible, to distort unevenly. Also there will always be the tendency to twist your two fork tube relative to each other, which of course is almost impossible, resulting in insensitivity of the front springs and the tendency of front end deflection.

Put a removed, complete forktube on top of a bearing, put another bearing on top of the tube and push down on the top bearing; you'll be surprised how much the top tube rotates out of its original position.

Or do a hard front brake only stop while trying not to put any steering input into your bars, and you'll notice that virtually any bike will always turn in the same direction due to fork deflection (even with two brake discs).

So I did what many road race teams and some SX/MX teams do and installed a bearing on top of each front spring, allowing the springs to rotate freely on one end.
The bearings are only about 1/4" thick, so there is no need for change in spacer length. (
That quote is from the guy selling the bearings) Furthermore they are 32 mm in diameter, so they self align. Also, the bearing sides (contact points) are so wide that, mounted on top of the spacer, the spacer sits entirely on it and the force transmitted from the spacer is evenly transferred onto the tube cap, preventing those ugly offset indentations you probably have noticed on your end cap.

It's apparently 32 mm in diameter and 6 mm thick. Beyond that I don't know. It must be akin to a Lazy Susan bearing. I'll let you know more when I get them. The diameter might be a tad small for an F since I'm getting them for 38mm forks. But at least I'll have some idea of a bearing number which usually indicates something about it's application.

OK, So What Bearing do I need?

Alternative to Bearings?


Forks By Frank

Another non-OEM fork suggestion - Forks by Frank: http://www.frankmain.qpg.com/. I've never used them, but heard good things - IIRC Flash has also recommended them. Marty #436

GS to Dakar Forks Conversion

I am trying to change out my GS forks for Dakar parts. It is the trying part that is my problem. I bought Dakar tubes, damper rods and TT springs. The stock little spring that goes in under the damper rod doesn't fit into the Dakar tubes. Does the Dakar not use this part? Also, the TT springs are shorter than my stock GS springs. The only thing that I can figure on this is that the Dakar doesn't use as much of a pre-load tube or none at all.

More trouble. I just tried the damper rods in the tubes. They are snug and the fiber ring that goes on the damper rod doesn't fit into the tube. The Dakar tubes have a slightly smaller inside diameter.


GS and Funduro Forks

Anyone know if BMW F650GS forks and BMW Funduro forks are interchangable? cdnabn49

Aftermarket Fork Opinions

Pros-Cons of TT Progressive Fork Springs?

I used to bottom-out the forks when riding off-road. Then I blew a seal. When I replaced the seals, I also changed from 7.5wt to 10wt oil. This made a big difference in fork stiffness, with less bottoming. However, the front is still a little soft in the ruts, and I was about to order a set of Touratech progressive springs. Then I read the FAQ and found this comment: "They were just so stiff that it did not make any sense for any kind of off road application."

Anybody have any comments on that opinion? Are the springs' princpal function to minimize brake-diving, and not so much for off-road bumps? Also, the TT site says to use 15wt oil with these springs. Would the oil alone minimize bottoming? (i.e., maybe I should try that first?) Scott, ID #1244

Hey, I have read the faqs on this topic a few times, but I'm just following up here... I have heard reports on the touratech progressive fork springs with diff. weights.... Just curious if this is worth doing for a f that mostly runs pavement,,,, Jacool3

Aftermarket Fork Protectors

What diameter is the top of the fork leg?

Q. Do the Classic Fork Protectors fit the GS/Dakar?

A. Yes but there is ONE very IMPORTANT difference. In their wisdom, BMW made a Fork Brace which basically leaves no room at the bottom of the Gaitor, on the Stanchion, for fitting Gaitors or protectors. However Stuflinn reports "BMW fixed the problem with machining for us. I just bought a 650GS, and then purchased some MSR fork gaiters for it. Of course the stock fork brace needs to be machined to make room for the lower gaiter. On the new GS that is in dealerships, the fork brace is designed for gaiters, and is sharply raked upwards in the center. This should also throw more air up into to the radiator. The pieces is outrageous for what it is (about $90.00), but it is a turn-key solution."

Q. If I installed a GS Lower Fender Kit, can I still fit the Gaitors on?

A. No, not without modifications. The Low Fenders, with the exception of the one from Wunderlich, all either push the OEM Brace UP or replace the brace with a similar one so it makes it even harder to install Gaitors. See the Front Fender Mods GS FAQ for further details.

Is there a quick way to install gaitors?

I recently bought an '03 Dakar and just changed the oil & filter today (thanks to the FAQs). My next M&M task, based upon all I've read here, is to install fork gaitors. I picked up a set from MSR yesterday...but I have a question: Is there an abbreviated method for removing the forks just to slip on the gaitors or do I need to go through the entire process outlined in the Fork Oil Change FAQs? I searched the forums and the FAQs, but only saw mentions like 'it only took me 45 minutes and 1 beer to install my gaitors'. Any step-by-step instructions out there? The seals on my bike are fine (only 2300 miles) and I probably will save changing the fork oil to 10wt until after the summer -- I'm too anxious to begin exploring all of those wonderful unpaved Rocky Mountain roads. Douglas80210 #1798

Wrap-Around Neoprene/Rubber Fork Protectors

NOJ Inc.

These are generic Neoprene wrap-around and Velcro on Type, for any Bike. On my Bike they look like this:



Wojtek #212 uses Neoprene Fork Guards made by Noj, Inc.(1-800-456-0485 or 1-612-926-8144). They come in several colours and work and look like the ones Glenn Metcalf has made. They cost $14.95 a pair and there's a $2.00 shipping charge.

Also available from:

Road Rider MC Accessories. sales@roadridermca.com

Cost : $14.95+Shipping.

Home Made Wrap-Around Protectors

If are Fork boots too expensive and too difficult to install, then Glenn Metcalf has a solution. An inexpensive alternative is to make your own. Glenn says his wife got out the sewing machine, and using soft-backed vinyl and some Velcro, made a pair of fork boots for his red F650. Off and on in a jiffy! See photo.

Seal Savers

I use neoprene fork boots from www.sealsavers.com. I had to grind a little off of the fork brace to get these fitted on the bike. andy112652 #1481

Concertina (Closed) Type Fork Protectors (Gaiters)

These are Full Length protectors like a concertina, made of either plastic or rubber. They look like this:

Gaiters (Concertina Type Protectors) - 1
Gaiters (Concertina Type Protectors) - 2 (Marty #436)



One option is /6 BMW boots on (part no. 31 42 1 234 908) available from your BMW Dealer. BMW 100 GS 1988 model part # 31 42 1 458 220

GS Installation Report 1

by Gerry #951

Q. Can I fit gaiters to my GS Dakar without modifying the fork brace?
A. Yes, but it's not the easiest of tasks

GS Installation Report 2

by BradG 1002

Gaitors on the GS with NO low Fender.

GS Fork Brace Alternative

After about 22K miles, the fork seals on my GS finally gave out despite all diligent attempt to keep the fork tubes clean by a good, frequent wiping with WD40 between runs. This was a real good time to think about installing fork boots so I opted out for this kit from Wunderlich (Part # 8160394) that, albeit being pricey at $120 from Santa Cruz BMW, fit the bill and looked good on the bike. Ken_WVHills #1405

Dual Star

Does this sound right for fork boots for a classic? The company is called Dual Star rather than the daystar mentioned in the faq. I measure that I need something that will go over the approx 60mm diameter of the top part of the stanchion and is at least 22 or 23cm long. Do you think the part number below is an appropriate size? I've never fitted boots so not sure what kind of slack needed etc....and the compressed length of 2 and 3/4 inches would mean that "at rest" the things would have to extend to about 3X their collapsed height.

For conventional forks with up to 13 of travel:
Fits upper tube dia of 40mm - 48mm
Fits lower leg dia of 51mm - 64mm
Collapsed height 2¾
20-01085 ... johnny canada #1088

Shield Type Fork Protectors

Another option for a fork protector are ones from Triumph. The Triumph fork deflectors install in minutes and look professional. Check you local Triumph dealer for A9641010 (Fork Protector Kit, T509, Tall Deflector) or A9641005 (T509, Short Deflector) See picture on left..

Tall Deflectors:

Triumph Shield Type Protectors - Off Bike 1

Triumph Shield Type Protectors - Off Bike 2

Triumph Shield Type Protectors - On Bike 1

Triumph Shield Type Protectors - On Bike 2

Short Deflectors:

Triumph Shield Type Protectors - On Bike



Triumph Protectors

by Kristian #562

Without the Low Fender the Triumph Fork Gators will JUST fit the GS/Dakar after a fashion, but will NOT be able to be installed properly, because of the existing fork brace.

I had them on my GS, but their purchase on the stanchions was only on about a 5-6mm lip at the top of the stanchion. Even rubbed a bit of grey paint off. i.e. the do not sit properly over the full depth of the protector seating band.

When I installed the G&G Low Front Fender even THAT lip disappeared. I'm thinking about some sort of Holder, but haven't got around to it yet.

Touratech Shield Protectors

Image by PabloDakar

Here are 2 pictures of the new Touratech Fork Protectors, TT# 300-0145, for the 2001-present 650 GS and Dakar; they are mounted on my 2002 GSA. These provide more protection than adapting the Triumph models (that only go ca. 2" up) and should not interfer with the air flow to the radiator (and thus not void the BMW warranty).

Last year I experienced overheating with my fork boots on and the disappearance of same when they were removed. Admittedly, this was during a summer ride to Georgia, but nonetheless, I wanted fork protection without the potential cooling problems (no comment here Flash). So I just installed the new Touratech fork protectors.

It took me about 15 minutes to install completely (instructions in German, and I don't speak/read German, and no English version on web site yet). There were LOTS of extra parts (which confused me...am I installing correctly?) that I suspect are for newer bikes with the low fender (spacers, new torx bolts, etc). $67 US, plus shipping and since I'm one of the first with them, it took 4 months! We'll see how they work (mud is still a problem), but they protect a lot more than the Triumph ones (see FAQs), and fit perfectly (and hence the heavy TT price). Greg #1245 SEVa

Wunderlich Fork Brace for Gaitors


BMW Fork Protectors

I know there are some BMW options as well listed in the FAQ but can anyone tell me what dimensions I should measure to see if some "off the rack" gaiters will fit? johnny canada #1088 - for a classic

Fork Protector Opinions

Classic Fork Protector Opinions

Q. I'm contemplating the purchase of some fork boots for my GS, primarily at the suggestion of a good friend and well-seasoned rider. With the variations of climate we have here in the Midwest, he thinks it would be a wise addition to my bike -- and I tend to agree with him after riding through quite a lot of weather and seeing some unique conditions both on and off road this last year. For those of you having experience with them -- what are the pros and cons? Anything in particular to be mindful of when riding with 'em? Installing 'em? Maintaining 'em? Just curious. Any observations would be appreciated. Thanks.

GS Fork Protector Opinions

MSR Fork Boots on a 2005 GS

I ordered a pair of thje MSR gaiters (part number is posted in another thread) for my 2005 GS. Yesterday, I took the forks off, carefully ground some meat off the brace and tidied it up with my Dremel so the gaiters would fit. I put the gaiters on (using slighly soapy water to ease installation) and discovered that each fold of the gaiters is so tight that they tend to 'bunch up' on the fork tudes as the tubes move up and down. I was hoping they would have better clearance on the fork tubes. Does anyone have recommendations for gaiters (boots) with more clearance for the tubes? Thanks. lagondacoupe

Fork Protectors and Warranty

What's the Story with BMW not Accepting any Radiator/Cooling Work on Warranty with Fork Boots?

Hot Topic - Feedback on the issue

Has anyone had trouble with over-heating after installing fork boots?

Fork Gaitors Void Warranty (GS/Dakar)?

I just received a letter from Wunderlich. Apparently, if you fit the Wunderlich Gaitors then BMW claims that, "the external temperature sensitivity limit of the engine is lowered, which could cause damage under extreme conditions. Therefore BMW are refusing any related claims." Wunderlich goes on to say that "none of our repeated tests, nor consumer feedback have confirmed these misgivings." Well, I'm not removing mine and having to replace the seals every 10' km again! Oyvind #1052 Bergen, Norway.

Overheating Feedback

OK, so we've debated this issue regarding BMW's service bulletin that says fork gaitors on a GS (2001 and newer) can cause overheating and void the warranty, etc. Right, so I've had gaitors on for ca. 1.5 years and never had a problem. That is, until this summer back in Virginia (recall I was in California for much of last year on sabbatical). Before the James Bay trip, I did a "test run" down to Savannah, Georgia (500mi) under very hot conditions (97 °F); slab for most of it. I had just done the usual checks, including coolant, and all was okay before I left. When I got to Savannah the coolant was gonzo (well, about one liter was gone) and the bike was overheating. I called my dealer (still warranteed) and they said "get rid of the gaitors, but we didn't see 'em on the bike (wink, wink)". I cut 'em off, replaced the coolant lost and returned a few days later (at a meeting in Savannah) with the temps in the 90's again, BUT no overheating at all. Hmmmm, maybe Satan is right. The James Bay trip was cool after we got north and I had no overheating. I discussed my empirical observations with Ike, who felt that the radiator surface area (not the radiator itself) seemed small in comparison to his classic, so maybe the gaitors do restrict the ventilation enough under very hot conditions (i.e., where we both live!).

So, I thought I'd share these observations. Just to cover my bases, the bike is well maintained, proper oil, etc., and ridden at sane speeds on and off road. Greg #1245 SEVa

Do Fork Boots Cause Overheating on Classics/ST?

Am I understanding the FAQ's correctly? The Classic F's do not have fan/overheat problems associated with fork boots? Only the GS and Dakar experience overheating? wontco #2003

I had no idea 10 weight fork oil made such a difference.
Switching to 10 weight should be mandatory for all riders over 150 lbs.
Thank you, FAQs! What a difference. Tempo #1908