Classic Hard Starting / Poor Running FAQ

compiled & edited by Kristian #562
Please read the Disclaimer before attempting any work in this FAQ.
Last Updated: 31 December 2006, by Winter #1935

• Introduction
• Diagnostic Tables
  • Table: General Diagnostics
  • Table: Classic - GS Starting Differences
• Misc Stuff
  • Hard Starts/Poor Running
  • Warm Non-Starting
  • Cold Non Starting - Petrol-Related
  • Cold Non Starting - Oil-Related
  • Engine Warm-Up
  • I don't have a Canister and still have "I can't be Outta Gas Symptoms"
  • Stalling Problems
  • Lurching/Jumping Problems

For other related FAQs:

• Looking for GS-Specific Symptoms? See Hard Starting FAQ GS
• Looking for Poor Mileage Symptoms? See Poor Mileage FAQ
• And then there is the Rotax 655 Troubleshooting FAQ

When you experience problems starting or running your F650, it could be related to any number of other smaller problems. So sometimes it can be very difficult to find what is wrong. This FAQ aims to help you identify what is wrong and redirects you to more appropriate FAQs with more detailed answers. Start with the troubleshooting table and see where you end up.

Please note: some of the entries in this table are sorta jokes - they are easy to spot (humor is the best medicine, but it will not fix your bike). There are also some stupid things in there such as leaving the bike switched to the "on" position. These are easy to spot as well... The table is symptom based, and for any one symptom there may be multiple causes. The possible cause/solution list is in order of what is fairly fast and easy to fix through to more difficult things. If you come across something that is incorrect or have something to add, please let us know. (Note: Items marked as FI are relevant on the Fool Injected (GS/CS/Dakar) models only. Items marked Carb are relevant on the Carb (Classic/ST) models only. Everything else is relevant to both bikes).

Also note that this table does not cover everything - it is a guide only. There are heaps of other FAQs that should help you out.

Q. My bike is hard to start/runs poorly. What should I look for?
A. It depends very much on the symptoms. The FAQs below might be able to help you out, they are in no particular order, but do the simple things first.

• Check your Battery. The F, especially the Classic, eats Batteries. Check your battery has water in it and check your battery terminals are properly grounded.

• Intake blockage. Check the condition of your Air Filter and make sure that there are no rags stored under the seat.

• Did you remember to turn on your fuel tap?

• Spark Plug not Fouled/Old? See the Spark Plug FAQ.

• Check the Idle Speed is up to 1400 rpms and the Idle Mix Screw (YES they ARE different things) is set correctly. See the Idle FAQ.

• Petcock not clogged, free flowing gas from tank to carbs.

• Make sure the air filter is clean and the choke is off (check at the carb, not the bar lever).......are you sure your choke goes completely off? With the "choke" circuit on these carbs, it usually runs really bad with a partially-on choke. I've seen the choke cable get hung up halfway, which leads to no running/stalling/no idle with choke seemingly "off" but will run fine but horribly rich with it full-on. Never leave mine ('99 Classic) on choke for more than a few minutes, if it's above 10'C (50'F), all I need is the choke to start, after starting, it'll run fine with no choke (totally stock 'cept for silly K&N). First thing to check is the action/adjustment of your choke cable. She should idle sweetly with no choke after just a couple of minutes. See the Proper Choke Use FAQ.

• Check you don't have a Broken Ignition Switch Wire

• Water in the Gas? Drain your fuel bowls (circled red) and check for water. You might have some in your tank too, and the problem will be worse on reserve if that's the case. Draining the float bowls is always a good idea and only takes a few seconds to do.

• Try replacing the spark plugs. Plugs properly torqued?

• Gas tank vent hose not pinched or blocked? See Tank Off FAQ.

• Clean the fuel tap (petcock) from the tank, drain the tank. Here's how to get the Tank Off.

• If when you try to start your bike all you get is the "Tic Tic Tic" sound coming from the Solenoid, (Large Round Object just Rear of the Battery on the Airfilter Cover with two big red wires coming out of it) this is symptomatic of a Flat Battery. It's the solenoid trying to close, and not quite having enough voltage to stay closed. It cycles back and forth when it doesn't have the voltage. Not good for the contacts either, can arc and overheat, melt a few things if you do it too much.

• Try cleaning the fuel filter (s). There's one in the Carb, it lives here (in the brown spigot between the carbs), one in the Petcock and if you put another one in-line, clean that. Same thing happened to me with both the big plastic cone type and the glass one. It's vapour lock. It seems that with the smaller filters, the smaller qty of fuel in there produces less vapour and cycles through fast enough not to cause a problem. I've been touting small filters here ever since it happened to me. Mark#403. See the Aftermarket Fuel Filter FAQ.

• Check the Spark Plug Caps. See the Plug Caps FAQ for more details.

• Are all vacuum lines unrestricted? The next time you "run out of gas", pop the gas tank cap and if your bike then runs fine, you have a tank venting problem.
  See the Canisterectomy FAQ.

• Check to see if both coils are plugged in to hot wire source. Not the plug end, but the input side of coil. The older ones have two coils and one of my (red/orange) wires came off after cleaning the bike with tank off. The bike will run on one coil, but not real well. See the Plug Caps FAQ for more details.

• Are your Valves properly adjusted? See the Valve Shim Check FAQ for details.

• It could possibly be a bad Voltage Rectifier. Check the Voltage Rectifier FAQ for details.

• You may have Split Carb Diaphragms. See the Carb Cleaning FAQ for details. You can check for a small hole or tear in one of the carb diaphragms, before you pull the carbs off completely for cleaning (a fair amount of work). Do the easy stuff first. Check the condition of the carb vacuum diaphragms. It you have a tear or hole, the slide will not raise, reducing you to a one-carb bike, resulting in low high-rpm power.

• Do you actually have water in your radiator? (Bike gets VERY Hot and runs poorly). Refer the Coolant Change FAQ and the Water Pump Seal Repair FAQ.

• If the green gasket under the filler cap has gone bad it will let water into the tank. When I got down to a certain level in the tank it would start to suck water. The green gasket was all expanded and was not making a good seal. Drain the tank and check for water coming out.

• Have you performed the requisite Canisterectomy and eliminated that as the culprit.? In the event that the canister has "fallen off", the rear carb port must be capped or it will affect proper idle and starting, not to mention sucking dirt and water directly into the carb. The vent hose to the gas tank, which was previously attached to the Canister, is now used as a drain vent, and is routed to the hose bundle by either footpeg. (I used the same side as the carb, the sight footpeg hose bundle.) There is a small brass connector inserted into that tank drain vent hose, somewhere where it runs above the air cleaner and carbs. It is actually a pinhole restrictive orifice which can clog. It should be replaced or the tank may experience vacuum problems. Some people replace it with  the smallest size plastic fuel filters, some people use a similar plastic nylon connector (which is not restricted) that is leftover from the removal of the other canister hoses. Assuming the bike is an OEM, the third sentence (of the tech Tips, which is slightly incorrect) should read: "This can cause problems in wet weather when the drain vent near the RIGHT footpeg sucks up water into the carbs."

• Have you pulled the Carbs & Cleaned them? Particularly Clogged Pilot jet(s). See the Carb Cleaning FAQ for details.

• If your Bike is Running Lean, i.e. idling faster, popping, check for Carb Intake Rubber Leaks (Carb Intake Rubbers), old ones can split or crack. Check this  spraying WD-40 in the suspected area while it is idling. This will speed up the idle if it IS leaking.

• A bad coil or sparkplug wire can cause your symptoms, but I would not expect these problems to occur so soon after the bike's manufacture. They usually show up after at least 10 years, in my experience. I would take off the seat and lift the carb tops off and check the condition of the diaphragms to make sure that there are no holes. This would cause one slide to be slow to rise (or no t rise at all) resulting in poor power and a low rev ceiling (low voltage to the plugs will cause similar problems). See the Plug Caps FAQ for more details.

• The coils don't fail very often, but wires do. Plug wires are a common failure on many types of vehicles, so they should be considered a weak link! Cheap to fix, too. You can test your coils, see the Plug Caps FAQ.

• When you have the high beam on, voltage (and current) are supplied from the green/black wire to the lamp. This goes through some series of switch contacts which is different from the contacts switched by "normal" ignition. Your ignition system may have a bad connection SOMEWHERE. Turning on the highbeam sends more current to it, via a different path. You need to clean and re-seat every damned connection associated with your ignition from the battery, through the ignition switch and everything else you can find. Do it yourself or pay someone else to do it. Either way, it has GOT to be done to make your bike run right, again.

• Problem: Low idle, chugging response, sounds sick. Culprit: Sticky choke cable. Solution: Make sure choke is all the way off once the bike is warm. Spray a lot of lube in it's general direction.

• The idle got faster and faster, each time I let off on the throttle. After one afternoon's ride, it was up to 2,000 rpm. I had just about convinced myself I needed to remove and rebuild the carbs...when I discovered that a bundle of electrical wires running by the rear of the left carb had worked its way down and was rubbing against the throttle control lever. That was sure an easier fix.

• Not unknown for exhaust problems to upset idling capabilities either - just to through something else into the mix. Are you getting hot legs?. Check the Exhaust Gasket Replacement FAQ.

• If you have a fast idle after taking your tank off for some work and it won't go down, it may be you've pinched the Throttle Cable somewhere under the Tank.

• About 3 weeks ago I asked for things to check to cure by 97 F650's hesitating (opposite of surging?) and got some great replies - use dry gas, use carb cleaner, clean air filter, put in in-line gas filter. It didn't seem like any of those suggestions helped - at least much. That is because the hesitation was my first "early warning symptom" that my chain had a problem. Today I had a new DID VM X-ring chain and sprockets put on (along with a new back tire), and . . . no more hesitation :-) I appreciate all the input I got, but know I know to add one more thing to the list: have you checked your chain? As a relative newbie and non-wrench, I wasn't all that familiar with chain symptoms other than check the adjustment (I wax it frequently) which I had been doing, but evidently not often enough. Now I know. Muriel #582. See the Chain Replacement FAQ.
  
  I had the same problems you have and checked everything. I run without the rubber snorkel on the air box; by dropping my carb needles down 1 notch, things smoothed out very nicely. Now comes the interesting part. I talked to a guy who has a ton of chain driven bikes. He said he also gets the same symptoms you are getting when he needs a new chain. I installed a new DID X-ring chain, and now the bike runs exceptionally smooth. Problem solved. Not sure if it will work for you. but it worked great for me. New site registration # 208. Member # 1297. Colorado Bob . See the Chain Replacement FAQ.

• Failed to Start. Check the heated grips are turned off, it just might make enough difference if you have a weak battery. After 2 months parked up with the alarm on, my GS would not turn over, until I remembered this. Adamx#1001. See the Battery FAQ.

• I just found out that the inductor sensor has problems when it gets hot and not when it gets cold. Make a note that if you have problems firing when the bike is warm to check the inductor sensor. My contribution, Tom Ikonomou.

• Fails to Start?. Do you still have the stupid kickstand switch? They have been known to screw up. Mike410(Iowa) See the Sidestand Kill Switch FAQ. See also the Ignition Switch FAQ.

• Fails to Start? The culprit may be a fastener on a cable coming from the starter; If it seems to have broken so that it no longer is fastened, it's that! If you are talking about that fat wire that attaches to the starter, below the exhaust ports on the left side of the bike, THAT is certainly your problem. Flash.

• It might be the Sprag Clutch i.e. when the starter engages the freewheel when trying to start the Engine.

• Bad Valve causing starting Problems?

• Is the KILL SWITCH in the RUN position?

• Electrical check:

  -Is the fluid in your battery between the lines? Put a voltmeter on the battery. Does your battery read at least 12V with the ignition ON? Hit the starter button and see what it reads while holding the button for no more than ten seconds. If it stays above 11V, the battery is not your problem.
  
  -Test to see if your solenoid is misbehaving. You can test this by using ONE automotive jumper cable from the +12V side of the battery directly to the big red wire at the starter. You don't even need to turn on the ignition. If it DOES crank, you have a solenoid (or wiring) problem. If all the big red wires and connectors are good and connections are all tight, it MUST be the solenoid that is bad.
  
  -Finally, the starter is held in by two bolts. Remove the ground cable from the battery first, THEN remove the starter. Hook the ground cable back up. Have someone help you with this next part. Hold the starter in BOTH HANDS with it's case touching the crank case and the gear FREE AND CLEAR of everything. Have your helper turn on the ignition and mash the starter button just BRIEFLY. If the starter tries to jump out of your hands and/or the gear spins, your problem is NOT your starter or your solenoid. Assuming your battery is good (which I don't) it is MECHANICAL, not electrical.
  
  -Remove one spark plug. Put the bike in gear. If you can turn the motor over by pushing the bike around or rolling the rear wheel on the centerstand, it is not any sort of cylinder lock.
  
  -If it is not something locking the crank or piston in the cylinder... then you will need to remove the alternator cover and pull the alternator. The sprague clutch behind the alternator may be messed up or else something has gone awry with the intermediate gears between the starter and the alternator.

  Flash 412 (CO)

  -Assuming that you used some type of heating device to install the new steering head bearings, take a good look for wire insulation that might have gotten toasted. Or possibly stretched/broken wiring to the handlebars while they were "dangling" off. Or whacked with a hammer while installing the bearing races. Marty #436

• Kristrian has got it right-it is your Sprag Clutch. If your bike has one of these-this is your problem. I Have an ATK dirt bike, which utilizes the Sprag Clutch and all you will get is a click like you have a bad battery. All you need to do is bump start the bike, and confirm that it will run fine. This Sprag clutch has springs and plates that when worn, will not hold, thus release and click instead of turning over the bike! KEM

• I drained the oil and removed the entire RHS magnetor cover, hit the ignition key, turn over not problem, Put the cover back on and click click, loosened the cover just a small amount, and the bike would turn over, not start mind you, no oil, or plugs installed.
  The resistance to turning over is directly proportional to the tightness of the RHSide magneto cover. I originally removed the cover while checking the gap on the pickup, reassembled, and no turn over, I cannot find any scoring marks, or tell tale signs of binding. Could it be that the starter motor is just becomming weak. I do not believe most electric motors do this, from exp.
  I do not have a torque wrench adapter for the mm hex, but I know torque, and with my finger tips I am only add a few a most, that is when,,,,, by sound i can hear the difference in RPM while cranking over, Gradually the resistance increases up to about 10 NM, then the motor will just go , ruuhh, ruhn, bzzzzzzz,  devir
   
  Leave the cover off and WATCH the rotor spin while cranking. Does it look straight to you? If so LOOK at the inside of the cover and see if there is anything protruding, anything that looks bent. Have you dropped your bike on the right side or has someone smacked into there? Flash 412 (CO)

• Are you SURE you got the cam timing correct when you put it back together? There are lots of ways to put the cams back in, most of them wrong. Even if the lines on the sprockets line up with the head, there is a 50/50 chance you got them wrong if you weren't paying attention to the lobes. Pour a tablespoon of raw gas in the spark plug hole, replace the spark plug and try it again. If it runs a few good licks, your problem is fuel delivery, not spark or valve timing. attention and/or know what you are doing.
  
  Is the cam with the little lever on it to release the compression place over the EXHAUST valves? That cam (with the compression release) should be the one on the exhaust pipe side of the head, not near the carbs.
  
  When you have the TDC crank-stop bolt in, do the LINES on the camwheels more or less line up with the top surface of the head when the tensioner bolt is loose?
  And when you crank the motor over TWICE (or more) and WATCH the valves, do they do this...?
  1) intake valves open and then close
  2) nothing happens for almost 360 degrees
  3) exhaust valves open and then close
  4) during the very end of step three, step one happens at the same time (known as overlap)
  
  If the answer to any of these questions is either "no" or "I don't know," then you need to be SURE that you have that stuff right FIRST.
  How far did you move the ignition timing when you moved it? HOW did you determine it needed to be moved and how did you set it.  Flash 412 (CO)

Q. Trouble restarting when warm. Hi I've got a 97 F650ST and when its been for a run and the engine is lovely and hot if I park up for a short while (5 -15mins) when I try to restart it the bugger needs 'choke'. Is this normal because its bugging me! Cheers from the Isle of Man.

• Trouble restarting. Instead of the choke, twist the throttle wide open and thumb the starter button. Works for me on a barely warm classic. Flash #412.

• That was the way my bike was when new. It needed the choke even when the air temperature was 90 degrees. I turned the idle air-mixture screws out 1/2 turn each, to 4 turns out, and never had another starting problem. Richard #230

Cheers & Rgds. Thanks to Flash, HsN, Andy UK and 1001 others.

Kristian

Petrol-Related

Andy Leeds UK #982
November '01

• Cold petrol is more dense and harder to vapourise (buy your fuel early in the morning, you get more for your money). "Wet" petrol burns but the steam produced changes the ratio or fuel to air. (water injection increases power but wears the engine). Metal tanks in particular condense old water vapour into the fuel, but plastic can too if cold enough. Cold air is also denser but in a different proportion into the fuel.

• The FI can't work out why the fuel is difficult to get burning (more fuel pressure/less air) but then produces a richer output (less fuel/more air). It gets the calculation wrong and the engine dies. Carbs are better because the human brain controls the choke and throttle.

• As for cranking power, turn the engine over first with the kill switch off (FI bikes may not do this or like this, but if they turn, they move oil). The starter motor can take two bites at the start, 1st to get the oil moving, compression and burnable mixture in the cylinder, 2nd (kill switch on) to get a good spark. This works with Ural's (kick starter 1st) and carbed F's at down to about -10 centigrade.

Feedback:

• Living in Switzerland I also (used to) suffer from winter hard times to start up my bike. My humble advise, what I do now and works just fine: pull the choke 1/2 way through but DO NOT touch the gas. Crank it for a couple of seconds /or till you feel the engine starts coughing up. Wait 5 or 10 seconds with the motor running before touching the gas, otherwise it may stall and then you get into the flooding mess and drained batteries you mention. Push the choke back in after a minute or so, you won't need it anymore. Somehow you learn to understand what your motor "prefers". It takes time, several trial and errors till you find it. Today even with temps going below minus 10 (and obvious poor battery performance), the bike starts like a beauty. Cheers, Fredo

Slow Starts on Cold Mornings - Oil Related & Engine Warm-Up

Various, January '02

• Cold temperatures increase the viscosity of Oil making it harder to turn your engine over and placing a lot of strain on your battery. Consider changing to 5W50 if you are using e.g. 10W50 or 20W40. See the Oil FAQ.

• If your battery is older than three years old you might want to consider a new one, especially if you have been straining it with cold starts. See the Battery FAQ.

• If your bike is cold, you will drain the battery very quickly trying to start it and a push start on an icy road on a cold morning is not a lot of fun and can be dangerous. Consider warming it up first. Some folks place a Hotplate (NO NAKED FLAMES.!!) under their bikes overnight or for a couple of hours in the morning, to keep the bikes oil warm enough to start.

• I had good luck last winter rigging a heat lamp above the bike (not to close) to heat up the oil in the frame somewhat. This was on the classic 650. I have Two fuel injected BMW bikes that start just fine in cold weather but the heat lamp might work for you. Dave#776

• Do youse cold weather riders find it easier for the engine to turn over if you disengage the clutch (i.e., pull the clutch lever to the bar)? My Classic seems to turn over easier in sub-freezing temps when the clutch is disengaged. Any of youse mechanical engineering types wanna try 'splaining it in terms I could understand why this is so? The only reason I thought of this is that the other day when it was REALLY cold I tried starting the bike as I was pushing it out to the street and it did NOT want to turn over. It was then that I realized that I wasn't hold the clutch lever in as I usually do. Pulled the clutch lever in and voila, the bike started. I usually hold the clutch lever in out of habit because one of my first bikes was a Honda that wouldn't start unless the clutch lever was pulled in. Now I have two habits, holding the clutch in and only starting when on the centerstand ('cause I never disconnected the side-stand cut-out switch). I wonder what's next. Shank

• When you're in neutral, the engine is still turning the clutch discs, just not the gears so when it's cold, you're still rotating thick cold oil. With the clutch disengaged (i.e. lever pulled) the engine turns only itself, not the clutch (or transmission). Nate

• With cold the oil in the bike becomes more viscous. Even when in neutral if the clutch is engaged you are turning the clutch assembly and a bunch of gears. Turning this through the thick oil is hard work and thus does not turn easily. With the clutch pushed in you are not turning all this, really you are just turning the main shaft, the cams and part of the clutch. MasterITRIT #F650-1231

• When the clutch is engaged in neutral, the entire transmission spins except for the output shaft. There are two shafts with a bunch of gears on them. Most all of the gears are spinning on their shafts. That is a LOT of "stiction" in a cold motor with cold oil in it. When you disengage the clutch, assuming that the plates free up, NONE of the transmission is spinning at all. The only thing other than the actual motor that is spinning is the input side of the clutch (the basket). I would suggest that if your battery is suspect and the weather is cold, that you put the bike in gear, pull in the clutch and PUSH the bike until the plates are free before you attempt to start it. That way, you KNOW the plates are free and the load on the starter/battery is a low as possible when you mash your happy button. Flash 412 (CO).

Generally BMW says start it up and ride off. Not like a maniac, but get going. You don't have to "allow it to warm it up", like in the old days, so long as you don't redline it past Mrs Jones House on the first straightaway.

• Those of you that have purchased a BMW motorcycle over the past few years, and have read the dumb rider's manual that comes with the bikes, may have noticed that BMW is warning against warming up a cold engine before riding it. The latest warnings appear to imply that the bike will immediately overheat and explode in a ball of flame, should you dare not to immediately ride away on the cold engine. None of this makes any sense to me. If the engine can't idle in your driveway for a few minutes in the morning, how can it survive idling for 10 minutes at at time during hot weather, while you are stuck in traffic? The only thing that makes any sense to me is that the warning is for the benefit of the EPA regulators to show them that there is an effort made to heat up the catalytic converter as soon as possible. (My Saturn car has a little air pump that turns on when the engine is cold to heat up the converter immediately. I assume that BMW was trying to avoid adding a similar pump to their bikes.) I don't see such a similar warning in the Japanese bike manuals and it bothers me to ride off on a cold engine. I don't see this as doing anything for the life of the engine. I would think that getting the oil circulating and warmed up a bit, along with getting the parts warmed up before asking the engine to do much work would be better for reducing engine wear. Richard #230, Pacifica, CA

• Does the oil really circulate properly at idle? I prefer to ride off slowly without straining the engine, knowing that with a few thousand revs the oil pump is operating efficiently AND the oil in the gearbox is getting warmed up as well. Just my 2d's worth. Paul W (UK) Dakar

• I'm with Paul on this. It's a waste of energy letting the bike sit at idle, warming up. I usually ride of with low revs and easy acceleration until the engine is warm. This way, tires, chain, transmission etc. warms up properly as well. Pretty much every manual I've seen (bikes & cars) said specifically to not warm up the engine letting it sit at idle. They all said to warm up the engine by driving / riding and taking it easy until the engine is warmed up. xls

• According to the manual, oil pressure at idle is only around 7 psi. Seems pretty minimal to me to those of you who want to let the engine idle cold for any extended period of time. I'll bet that oil pressure is much higher at a fairly moderate 3000 rpm. OTOH, there is plenty of experience that an engine should not be run hard until it has had a chance to warm up to full operating temperature. Seems to me there's plenty of room for choice somewhere in between. Todd #389

• My father (an engineer) taught me as a child that most engine wear does occur when an engine was cold and that they warm up faster by driving. This has always been my belief. I have a riding buddy who's dad always took the car engine to valve float a few times cold to warm it up faster. I think that is a bit extreme.
  The question is BMW's owners manuals. Much of the manuals are the same from bike to bike.
  The problem is R259 powered motorcycles. These bikes have an idle up (labeled CHOKE) that takes the throttle bodies out of sync. This devise does not make the engine run richer in any way just faster. If you warm this bike up with the choke on you have a very fast running very lean out sync engine that is largely air cooled. A guy starts his bike on choke, runs into the house for a minute or so to finish whatever, the phone rings and all of a sudden the phone call is more important than the bike bike ride and the bike is forgotten. If you bike is a R or a G/S most likely you won't ruin the engine. They normally melt the wires to the hall sensor and die first. If you have a RT, RS or worst of all RSL, with plastic bodywork directly above and around the single wall white hot glowing exhaust pipes the least you do is melt the plastic. Setting it on fire is not out of possibility. The other question was riding in stop and go traffic. If I did a lot of that I would be sure to ride a liquid cool motorcycle. I have seen badly melted fairing lowers on R1100RT's and R1100RSL's from doing this. As far as I know it won't hurt to idle a BMW K or F bike for ever. This is my 2 cents on warming up your engine. This is my 2 cents on warming up BMW's. Stuportech

• The real deal is all about emissions. When the engine is cold the fuel mixture must be richer to make the engine run smoothly and start easily, this with less complete combustion and a cold cat will cause greater emissions. When being ridden the engine will warm more quickly. BMW is very (over I feel) committed to the environment and the make some of the cleanest running bikes around. Most auto manufacturers tell you to drive away as soon as the engine will respond to the throttle smoothly, and in mild weather that's immediately. They cite extended idle when the engine is first started will cause cat damage. JB
   

I don't have a Canister and still have "I can't be Outta Gas Symptoms"

• Typical Question. The other day I was putting along and all of a sudden pfft. I ran out out of gas. I checked the inline fuel filter and it was dry but there was half a tank of gas in the tank. I know there is a write up in the FAQ but it only relates to the canister. I have no canister on my bike. Has anyone had this problem ? Alvaro #890.

• The consensus in this group was that it was vapour lock due to using a filter that was perhaps too large, combined with hot weather. Others thought that because the fuel is gravity fed, is was simply not feeding fuel fast enough to keep the filter vessel full. I simply chucked the problem filter and switched to a smaller one -- have not had any problems since. Tom

• I recommend first checking the tank breather. If you don't have a canister, it may be either a hole in the cap that needs to be cleaned, or there may be a rubber tube under the seat that relieves the tank pressure. If your bike has a hose that vents to the atmosphere and connects to the tank, sometimes they get pinched when you reinstall the seat or tank. Of course, I have two very large in-line filters on my bike and have never had a vapour lock problem. However, I can never find any hot weather to ride in. I consider myself fortunate to see the sun once in a while. Richard #230.

• I recommend (after checking your vent lines) running the smallest little in-line cone-shaped filter you can find. My bike quit a couple times from Vapor lock when running a bigger filter in warm weather. Mark #403

For the GS/Dakar, see This FAQ.

Q. After riding constantly for around 100 miles my bike stalls below 3k rpm. The oil in the tank is also full of bubbles. It is a 1995 classic with 14k miles on the clock. I put up a message about this before and was advised to run a compression test to see if I needed new piston rings. Well I've just done this test as described in the FAQs. With a warm engine, decompressor restrained, the compression read 12.5 bars, with a teaspoon of oil in the cylinder it read 13.5 bars. This seems to indicate the compression is fine. Bike has been fully serviced by me at 12k. My local BMW parts supplier has said to me that they have come across this problem before and they are suggesting that I replace the alternator. If this doesn't cure the problem I can give it back to them and get a refund. Any ideas?

As it's a 1995 model F650 could it be a fuel or a fuel-mixture problem?
I've changed inlet manifolds as they were cracked, but to no effect. The idle mix screws are stuck fast, but if this were the problem would it not cause rough running at other times. The problem only occurs on long trips (100 miles +) and goes away when the bike is cooler

Have you done a "plug-chop" at various revs?
I'll have to look up what this is!

Have you tried riding with the choke lever in various positions when it happens or when it is about to happen?
No. But I did increase the idle to 1500rpm, with no effect. If I keep revs over 3k it doesn't stall

Do you get any warning that it's about to stall and just it just die? or splutter first?
The idle starts to falter, then dies, usually standing at the lights. No spluttering

• The alternator has nothing to do with your problem of bubbles or of stalling. Perhaps the black box is failing when hot. Try placing one of those "instant ice" packs (that sports players use) on it for ten minutes or so (located in the tail section) and see if that fixes the problem. If not, stick it on the VReg and see what happens. The bubbles are not related to the stalling. Flash #412 (CO) (refer the Voltage Rectifier FAQ and try and identify your symptoms there.

• It sounds to me like your idle-mixture screws may be set too rich. When the bike gets really hot from a long ride, the idle mixture becomes too rich for the hot engine and it stalls. The mixture screws have almost no effect above idle speed. I would recommend soaking them as much as possible in WD-40, or similar light oil and then trying to remove them by force. There are special tools that are designed to remove damaged screws. You might try one of those, also. Before doing this buy some new mixture screws to replace the ruined ones. If the carbs were off the bike (and all gasoline was removed from the area) and if all else failed, you could probably remove the screws by heating the aluminum around them. Richard #230, 1997 Funduro, Pacifica, CA

• Flash, here I must disagree with you!!! if you remember I had exactly this problem last year with loads of air bubbles and failing to run below 3000rpm after about 2hrs of riding, at the end of the day I changed the rings and it has run perfectly ever since, NO air bubbles, bags of power lovely tickover even after 2-3 hours of riding. Sorry to disagree but it had to be said, Keith UK #914.

1. Check the Clutch Adjustment. See Clutch Adjustment FAQ or the Clutch Misc Probs FAQ.

2. Check Routing of Clutch Cable. See Cable FAQ.

3. Check the Chain/Sprockets. See the Chain Replacement FAQ.

4. Check the Petcock is on. See the FUEL PETCOCK FAQs

5. Check the Fuel Filter is Not Blocked. Carb Misc FAQ

6. Check the Carbs. See the Carb Clean FAQ.

• Bike lunges/jumps at speed! I have a 98F with 19,000 mi on it. I've been having problems with it running rich (carbon on the plugs) since the 18,000 mi service (done by me). I put a tank of carb cleaner in it thinking that it would remove the varnish on the carbs/jets/fuel valve in hopes of that fixing the problem before I had to remove/clean/refurbish the carbs. Now at about 5500 rpm the bike will cut power while the rpm's go sky high. I would think that this is either: The carb is choked, which momentarily cuts the engine and when it starts back up I've pulled in the clutch so it revs sky high. Or: Totally unrelated to the carb problem, it's jumping out of second gear (the only gear that it seems to do this in). It's only done this since I put that stuff in the tank. I've done some more test riding and have narrowed down the situation. When I accelerate in 2nd gear, coming out of a turn, power to the rear wheel will be cut while the revs shoot up to redline. It stays in 2nd gear. It feels like pulling in the clutch with full gas, at speed. I don't think it's carb related, since the carb is doing exactly what it should. At 3/4 throttle, if the clutch is disengaged, the revs should go sky high. So, what is causing the clutch to disengage? I assume that I need to pull the clutch and start there.  c_d_mayo#643