Classic Valve Shim Check FAQ

by Kristian #562, Flash #412
Additional comments by Shank, Paul in NJ,
Please read the Disclaimer before attempting any work in this FAQ.
Last Updated: Sunday 22 October 2006, Winter #1935

Other Relevant FAQs:


This FAQ is only for CHECKING the Valve Clearances. For performing a Valve Shim Change once you have ascertained they ARE out of spec refer The Valve SHIM CHANGE FAQThis is a simple job you can do yourself and save some money doing it. BMW recommend the Valve Clearances are checked every 10,000km or about 6000 miles. You should only change the shims when they are OUT of spec. If you are new to all this or have additional questions, it is recommended you also read the Valve Misc. FAQ.


The "Classic" BMW Manual specifies:
0.10mm ~ 0.15mm or 0.004<94> ~ 0.006"
for Both Intake & Exhaust

For specifications for the Fuel Injected bikes, see the The GS/Dakar Valve Shim Check FAQ.

Testing The Gap
The idea is that the gap should be anywhere between or EQUAL to the specs. The large feeler gauge should NOT fit between the cam and shim. (OK, a REALLY tight fit is probably acceptable.) The small gauge MUST fit between the cam and shim. (If it doesn't... you are likely on your way to a burned valve.) The ACTUAL GAP will be anything in between. Since the shims only come in 0.05 mm (0.002") increments, there is only ONE shim that will put you within the proper range of adjustment. I don't generally do all the math. I just stick the feeler gauges in and the small better go and the large better not go. If that isn't what I find, I stick the next gauge in (up or down as required). Normally you don't jump two shim sizes in 6k miles. So this is just a verification check. Measure the shim that came out and put the next size, up or down as required in there when you put it back together. Flash#412


What is the Part No. of the TDC Bolt-Location Crush Washer?

It is an A8x13 copper washer available at a lot of good auto Shops. Aluminium Works OK too. BMW Part No. 11 11 2 343 010.


The bike MUST be cold, even after 4 hours I got a 0.01mm difference when compared to leaving it overnight and checking it again.

Taking it Apart

A. Remove GAS Tank

Why? To access the Valve Cover.
How? See Gas Tank Removal-Replacement

B. Remove the Valve Cover

  1. When the Tank is off you faced with this: The Valve Cover. View from LHS. View from RHS
  2. Gently pull off your Spark Plug Leads and remove a Spark Plug. This will allow the Crank to be able to go a full cycle without fighting against Cylinder Compression.
  3. Removing the Valve Cover entails undoing 6# M10 Bolts. You should leave the Valve Cover attached to the Breather Pipe, put a cloth around it and tie a piece of string through a couple of the boltholes, hoist it up, removing it out from the LHS Side of the Bike and over your handlebars and tie it firmly in place, out of your way. Don't twist the Breather Pipe Hose (let it rotate at the Valve cover if possible) if it's an older pipe and brittle, it may break. The OEM clamp holding the cover vent to the vent hose is non-reusable, so if you do take it off have a spare (small, about 10-12mm) hose clamp handy to replace it. You CAN get those OEM clamps back on, but it's not easy and not always as tight as when you take them off. Bottom line is you don't need to remove it.
  4. The Cams and underneath them, the Shims, will be exposed.

C. Setting the Cam Gear Wheel Timing Marks Correctly

  1. Remove the plastic plug on the right side of the crank case with a Coin or Screwdriver. Don't worry, no oil spills out!
  2. Insert an Allen Key into the Hole where the Plug Was and turn the crankshaft with a hexagonal socket (clockwise) until the markings on the camshaft sprockets are in one horizontal line. See this picture Turning Crank to get Piston at TDC.


    BMW put the Cam Timing Marks on the LH Face of the Cam Gear Wheels, so you have to look at those from the LHS of the bike, but turn the Crank from the RHS of the Bike, which can be a bit uncomfortable. You then do not need to remove the Plastic Plug and turn the crank with an Allen from the "Wrong Side" of the bike. You can simply put the bike in gear and roll the rear tire until the lines on the cams are parallel to the valve cover surface of the head.

    LOOK at the cams on the valves. Either the "pointy" ends of the cams will be pushing the valves partially open (overlap) or else the pointy ends will be up in the air and the round ends on the valves (TDC on compression).
  3. Important! Note that it is possible to have TDC twice, 180 degrees apart, with the Cam lobes pointing inwards or with the Cam lobes pointing outwards, each being one of the 4 cycles of a 4-stroke engine. For this operation, the Cam Lobes (the Pointy, rather than the rounded ends) of the cams must be facing Outward. The Exhaust Cams (Closest the Exhaust Header) must point (Pointy end) to the front of the bike and the Intake Cams (Closest the Intake Rubbers, Pointy end) must point to the rear of the bike. i.e. They should look like this: Camshaft Carrier Lobes Out.
  4. For what the Marks on the Timing Gear Wheels look like after you've got TDC see here: Timing Marks.
  5. Note that one person found his timing Marks would NEVER line up, because the Factory had put one the Cam Chain on with one of the Wheels off by ONE Tooth!

    Here's a picture of what it should NOT look like:

    Note! Marks don't line up?

    Don't assume your Cams are out of time (off one tooth) straight away. Try this first:

D. Inserting the TDC Bolt

  1. After you've got the Piston at TDC, you need to keep it there by locking the Crank with the TDC Bolt.
  2. For a picture of the Bolt that holds the Crank at TDC see here: TDC Bolt (Hint. It's not the Spark Plug ;-) )
  3. For a picture of where the TDC Bolt goes see here: TDC Bolt Insert Location (You must take out that Shiny Silver Bolt First).
  4. For putting in the Bolt at TDC, if you're going to take the Valve Cover off anyway, put the bolt in AFTER you get the cover off, so you can see which way the Cam Lobes are pointing and you can see the Marks on the Cam Gear Wheels. Put a ratchet (Or use the Rear Wheel) and a socket into the RHS Magneto Cover (This is where you turn the Crank to get the Piston at TDC), because then you can lie on the LHS of the bike, look into the hole where the TDC Bolt should go and reach under the bike and turn the Crank until you see the hole, then put the TDC bolt in. Use a flashlight. You can also gently finger tighten the TDC locating bolt until you can actually feel it lightly seat in the slot/mark on the flywheel.
  5. TDC on compression (i.e. Cam LOBES Pointing Outward as noted above) is where you want to lock it. Remove the screw that occupies the hole into which the TDC bolt goes and slowly screw the TDC bolt in. When you feel it touch the crank, rock the rear wheel a few inches back and forth with one hand while you slowly screw the bolt in with the other. There will be a place where the "drag" will suddenly disappear and you can turn it a couple or three more turns before it touches. THEN, you'll find that you can no longer rock the wheel. You are THERE.
  6. If you're confident you have the Gear Wheel Marks lined up at TDC, you can simply measure the Valve Clearances without the Bolt. Just don't move the Rear Wheel. Put the Bike IN GEAR, this helps "lock it" while you're measuring your clearances. The Downside of this is you MAY be a slight bit off each time. With the Bolt you're always measuring the Clearances at the same Crank Position.

E. Measuring the Clearances

  1. OK you've got it all apart, set the Cam Gear Wheel Timing Marks Correctly and inserted the TDC Bolt. Now you need to measure the clearances between the Cams (egg-shaped things) and the Shims (Silver Disc UNDER the Cam Lobes).
  2. You can put feeler gauges in the Front TWO as they are easy to access. Just slide (wiggle gently) the Feeler Gauge UNDER the Cam Lobe and on top of that disc. These are marked GREEN in this Picture. The space is VERY SMALL.! Use the gauge on the low side of the specification first and work your way up until the gauge doesn't fit in. You want to note what size gauge you can BARELY force in there without bending the gauge.
  3. Try and check to the nearest 0.01mm. You can double up two gauges to get finer increments, just make sure they are clean. Even oil has a finite thickness. You can easily combine a number of the feeler gauges (just add the numbers) if you don't have individual ones for every 0.01mm from 0.05~0.20 say. For a picture of the direction the Cam lobes should be in at the time of measuring, see here: Cam Lobes.

  4. For the BACK TWO, you must insert the Feeler Gauge in the about 10mm x 3mm Slots in the SIDES of the Aluminium Cam Carrier (Marked RED in the above picture) to access the Cam Lobes.
  5. Note when checking the shims and clearances, the numbers are never exact. This is definitely true when using a feeler gauge. Even the Shims can be off a bit from the .05 mm increments.

    Recording Shim Measurements

    Draw a Cross on a Piece of paper representing:

    Front of Bike
    Rear of Bike

    Write DOWN your Clearances in each square

    Note: I'm using the TDC bolt (homemade: BMW's never heard of such a thing!) as well as looking into the hole while rotating, looking for the middle of the detent, so I'm pretty confident about lining cams up properly, but I note the point about sliding the gauges in when readings mysteriously changed. Also, once there was a tiny grain of sand (I live in a desert, go figger) on my micrometer, so all my spare shims all went up by .05mm later in the day, leaving me rather disconcerted until I noticed the sand. Have to be really careful about that in the future. Aleksander in Dubai 98ST

F. Replacing the Valve Cover/Tank

  1. Check the Seal Surface of the Valve cover is clean, Check the seal is in its groove, Replace the Valve Cover, Torque the bolts to 10Nm.
  2. Replace the Tank. See Gas Tank Removal-Replacement
  3. Don't Forget to Remove the TDC BOLT before Restarting your Bike.
  4. Don't Forget to Replace the Plastic Plug in the RHS Engine Cover.

That's it!

Many thanks to Flash, Richard, Todd, Marty436 & Johnathan Gifford,
for all their very constructive comments which are reflected in the FAQ.