R1250GS Valve Clearance Check

R1250GS VALVE CLEARANCE CHECK PROCEDURE
Note:
This procedure was written for the author for his own service notes and general interest. It should not be relied upon as being factually correct. When performing DIY maintenance, it is essential to follow manufacturer service manuals and guidance.

1. Remove Coil Cover
a. 1 x T25 (5Nm)

2. Disconnect Coil & Removed Spark Plug
a. Unclip electrical Connector from Coil
b. Slide Coil electrical supply cable from Rubber Grommet
c. Remove Coil (Specialist Tool)
d. Remove Spark Plug (14mm) & (12Nm)

3. Remove Rocker Box Cover
a. 3 x T50 (10Nm)
b. Tray to Catch Oil (~ 200mil)
c. Remove Gasket and inspect (No need to replace if OK)
d. Remove and inspect the Spark Plug Gasket (No need to replace if OK)

4. Remove Top Dead Centre (TDC) Inspection Bolt
a. 1 x T50 (New Washer Required) – (30Nm)
b. Washer: Int diameter ~ 16.5mm, Ext diameter ~ 22mm

5. Acquire TDC Alignment
a. TDC Check 1 (8mm notch appears concentrically, in the middle of the inspection Hole)
b. TDC Check 2 {The Cam end should be positioned with L & R vertical sides & labelling at bottom}
c. TDC Check 3 (Piston all the up at TDC. I use an old chop stick to pop in as additional check)

6. Select 6th Gear and use wheel to rotate CCW to turn Engine
a. It’s possible to gently rock the rear wheel gently CCW (normal travel direction) whilst observing the TDC Inspection Hole

7. Measure Valve Clearance (Always with COLD Engine)
a. 4 Valves in each cylinder (2 Inlet Valves & 2 Exhaust Valves)
b. INLET Valve Clearance: 0.10mm to 0.17mm
c. EXHAUST Valve Clearance: 0.34mm to 0.41mm
d. Be careful of sticking feeler blades!
e. You want a nice drag with two fingers pushing/pulling on the feeler gauge.
f. Measure each of the four clearances and record on work sheet

8. Measure & Replace (if necessary) Valve Shims
a. Remove Black Solenoid
i. 3 x T30 (10Nm)
ii. Unclip electrical supply cable (same mechanism type as Coil)
b. Remove Axial Fixation Pin (looks like a C clamp) – 2 x T30 (10Nm)
c. Mark (paint dots) selected cog teeth for post re-installation (wipe clean first)
d. Remove Cast Bracket – 10 x T30 (10Nm)
e. Remove, inspect and replace the rubber spark plug seal.

9. Measure Valve Shims
a. Each Shim is partially held in place by the black follower arm. The Inlet ones are hinged at the top. The Exhaust ones are hinged at the bottom and fall back when the cast bracket is removed.
b. Using a magnetic tool, remove each shim and measure and replace until the new shim is inserted.
c. When inserting a new shim, apply a film of oil to both sides.

10. Calculate new required shim
a. Use a good quality micrometer
b. The Valve Clearance and the Shim Thickness are in Series. So, if the clearance is too large, the shim thickness needs to increase and vice versa.
c. New Shim Thickness = Current Shim Thickness + Current Clearance – Target Clearance
d. Example: 2.16mm+0.40mm-0.34mm = 2.22mm (From one of my Exhaust measurements)
e. You will probably have to nudge slight up or down for your new shim size. This is because the shims are normally only available in multiples of 0.02mm

11. Move to the other Cylinder
a. Prior to moving to the other cylinder, complete the one you’re working on. Its absolutely necessary to fit the new shims, replace the cast bracket, axial fixation pin and solenoid and torque up (slowly and evenly).


12. Re-Installation (Reverse order with special attention to)
a. Lubricate the exposed components with a small brush (shim holders, cam lopes, cam chain etc)
b. Refit the cams locating the teeth with the ID paint dots and carefully hold both whilst fitting the cast bracket. (make sure the 2 black exhaust followers are swung back up first and the black rubber spark plug seal is fitted)
c. Remember all the bolts are 10Nm. Don’t over torque.
d. When fitting the Rocker Box Cover, check the spark plug gasket is fitted
e. Don’t forget to fit the rubber pad at the bottom. Fits into a square recess and hinges on each side.
f. 10Nm for the bolts. Don’t over torque.
g. Insert Spark Plugs and reconnect Ignition Coils.
h. Each cylinder will lose approximately 200mil of oil. So, add 300-400 mil of new oil prior to restarting engine.
i. Start Engine, let idle for a while whilst checking.