Stephen Karlan (Dali Meeow) - email@example.com
Step One: Remove the black plastic alternator cover at the front of the
engine using a 4mm Allen wrench. This black cover is behind the front shock
and, after the Allen screws are removed, jiggle the cover and let it drop
past the exhaust headers to free it. With the cover off, the alternator
belt is visible. Check the tension of the alternator belt; it should move
only slightly with thumb pressure. Leave the alternator cover off.
Step Two: Move to the cylinders, those silver jugs that jut out the sides
of the engine. Remove the black plastic strip ["4 Valve" imprinted
on part] by hand; this plastic part covers the spark plug area.
Step Three: Remove plug wire from the plug by using the 2-inch long black
plastic loop tool supplied in the bike's took kit. The plastic loop tool
acts a handle for removing the plug wire from the end of the plug. Holding
onto the loop end, point the open side of this 2-inch plastic tool toward
the rear of bike while hooking the tool onto the plug wire boot. Pull on
the tool to remove the plug wire.
Use compressed air to blow out plug hole before removing the plug. Some
camera shops might sell expensive compressed air used in cleaning lenses;
this is over kill. If you don't have a compressor, use a straw or small
flexible plastic hole and blow. There will be stuff in that hole that you
don't want in your cylinder ! You'll need lots of lung power here.
Step Four: Remove the spark plug using the deep socket supplied in the
Step Five: Place a pan or some newspaper under the valve cover to catch
the small amount of oil that will drip when you loosen the four valve Allen
screws that secure the valve cover. Loosen the four Allen screws with a
6mm wrench and remove the valve cover; tap lightly if it's stuck.
Option One: Return to the alernator area and locate the 5/8-in. or 17mm
nut (depending on bike) which is the lower alternator drive pully. Place
a socket on the nut to turn the lower alternator drive pulley (and engine)
clockwise. As you turn the alternator drive pully, the cylinders (and valves)
Option Two: This method requires that two persons work together. Put the
bike in gear and, with the bike on the center stand, carefully rotate the
rear wheel to move the cylinders the valves (but not the bike).
Step Seven: Now that you can move the cylinders (and the valves) you will
want to position the valves for adjustment. There are three ways to do this.
Method one: Remove both spark plugs and place a long screwdrive in the
cylinder next to the first set of valves you are going to adjust. You can
adjust the left or right side valves first; it makes no difference. Place
the screwdriver tight against the piston crown. [ Do not use a wood pencil,
Chinese chop stick or soft wood object because a piece could break off inside
the cylinder. Removing the piece could be complicated and expensive.] Rotate
the alternator nut clockwise or the rear wheel until the screwdriver projects
the maximum distance out of the cylinder. When the screwdriver is at maximum
extension, check the valves on both left and right side -- adjust the valves
on the side where the adjustment gap "wiggles". Step Eight will
explain how to adjust the valves. After you adjust the valves on one side,
it is a good time to perform the rocker arm adjustment; see the directions
near the end of this article for that information. After adjust the valves
on one side, move the engine 360 degrees by rotation the alternator bolt
or the rear wheel, and adjust the valves on the other side of the engine.
Method Two: Instead of using the screwdriver in the cylinder, you may
remove the round black rubber timing hole cover (size of quarter) located
on right side of engine (above and to the rear of the cylinder head, below
ABS wiring, over the flywheel) by grabbing the edge of the cover with a
hemostat (medical tweezers, needle-nose pliers) and pulling. Timing marks
will be seen inside of this hole.
If you are going to position a cylinder by using the flywheel marks, you
need a flash light (small Maglight or flexible stalk flashlight) to illuminate
the flywheel marks inside the timing hole. The marks,in the order in which
you will see them inside the hold and on the side of the flywheel,are "Z",
"S" and "OT". You want to center the "OT"
mark in the opening. If you position the cylinder in this manner, you may
check your work by inserting a screwdriver as explained in Option 1.
Be careful when reinstalling the small rubber cover that you do not push
it all the way through, into the hole. When reinstalling the timing hole
cover, especially on RT models where it is extremely difficult to reinstall,
use a needle and heavy thread to sew a loop in the cover so that you can
retrieve the cover if you push it into the hole. Place the loop in the cover
so that, when the cover is in place, you can pull one end of the thread
to remove it from the cover. If you damage or destroy this timing hole cover,
clean the hole area with gasoline and cover it with duct tape while the
dealer obtains a new one for you.
There is an optional method that I will designate Method Three for moving
the cylinders into place. This is not recommended and is presented only
to be complete. Put your finger over the spark plug hole and feel for air
pressure; when the pressure stops, the piston is at maximum extension (the
top of its stroke) and the valves are in position for adjustment. When used
in conjunction with the flywheel marks, this will work. I have never been
able to feel the air pressure at the spark plug hole because the hole is
Step Eight: Adjust the valves using a 10mm box wrench, 3mm Allen wrench,
two feeler gauges and a small torque wrench. A torque value of only 6 ft./lbs.
must be observed because overtightening will damage the threaded adjuster.
BMW recommends the following two feeler gauge dance step. One gauge is used to adjust the intake (or exhaust) valve while the second feeler gauge is positioned under the adjoining intake (or exhaust) valve to stabilize and prevent the rocker from canting.
After the first valve is adjusted, stabilize it and adjust the second
valve. To ensure that a valve is properly adjusted, attempt to insert the
next thicker size of feeler gauge -- the feeler gauge should be too thick
to fit into the gap. The valve clearance may change slightly as you tighten
the lock nut. Experiment with tightening technique to maintain the gap as
you tighten, and recheck the gaps after all four valves on one side of the
bike have been adjusted. (The terms clearance and gap are synonymous.)
Optional three-gauge method to check valve clearance. For the exhaust, use three gauges sized 0.011, 0.012 and 0.013 inches. Use a 0.012 for stabilization of the valve adjoining the one being adjusted. On the valve being adjusted, the 0.011 should pass with no drag. The 0.012 should have a "light drag" and the 0.013 should not pass. This helps develop a feel for the desired "light drag". It cross checks the adjustment. (Submitted by Brian Curry in Chester Springs, PA firstname.lastname@example.org).
I own a special set of feeler gauges on which each gauge has two thicknesses. The 3/4-inches at the tip of the gauge will be 0.012 inches, the gauge then increases in size to 0.013 inches. When using these gauges, the 0.012-inch feeler gauge should fit with some drag (GO), but the 0.013 part of the gauge should not pass (NO GO).
The two exhaust valves are located nearest to the exhaust pipe. Adjust exhaust = .012 inches (.30 mm). If you err in adjusting the exhaust valves, err on the loose side. It is important that you do not adjust the exhaust valves tighter or smaller than 0.012 inches (.30 mm). Adjust intake = .006 inches (.15mm).
Adjust both the intake and exhaust valves on one side of the engine. Then adjust the rocker arm on the same side of the engine if you're going to do that. Only then should you rotate the engine 360 degrees and adjust valves on the other side of the engine.
.30 mm .012 in.
Intake Valves .15 mm .006 in.
The author has done his best to produce accurate information. However no responsibility can be accepted for any damage or injury caused by any errors or omissions in this article. Make certain that you understand what is described and why it is being done. Use at your own risk.
Updated 2002 for clarity, all clearances have remained the same. Rob Lentini, an experienced and superb mechanic and engineer, has some different clearances and procedures to obtain more low-end torque and engine characteristics which he enjoys. The values presented here are factory settings.
Comments, corrections and questions may be directed to
Stephen Karlan (Dali Meeow) at (305) 255-1010
or via email at email@example.com.
Updated November 23, 2004.