zombiepotatosalad
New member
I want to set the valve clearances right, but I saw in a video that part of the procedure is setting the timing mark correctly. How do I do that with this model?
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Rotate the engine until the OT mark on the flywheel is in the center of the timing window and one of the cylinders has detectable play at both valves while the other cylinder has no play with either valve. The timing window is the round hole, probably with a rubber plug, on the side of the engine case.
Then adjust the valve clearance on the side that had some free play to begin with. Use a feeler gauge between the end of the valve stem and the rocker arm.
When done with the first side rotate the engine exactly one full revolution until the OT mark is centered in the timing window. Repeat the clearance adjustments on the second cylinder.
Use the specifications for the clearances on your engine. These have changed over time and I am not sure what current wisdom for clearances are. I was always happy with .006" intake and .010" exhaust. There may be later Airhead wisdom about to be provided, I hope.
Here's the thing... I don't see a flywheel behind the rubber plug.
Here's the thing... I don't see a flywheel behind the rubber plug.
On my 88 R100 RT, it depends on how and where you are looking. The flywheel teeth are barely visible at the front of the hole, and the OT/S mark and Z/F mark (Kurt called it the F mark, but it's a Z on my bike) are only visible when directly in front of the hole. I don't know how you're rotating the engine, but those markets can go by fast if you're not paying attention. It's best to go slow while watching the timing hole. As others have mentioned, bumping the wheel works well too. Also, I'm assuming you have the spark plugs out, since it makes rotating the engine much easier. I know when I first started, I would see those marks go by the window fairly quick and it took me a while to learn how to go slow enough so that I could stop at the right point.
Right, but it seems to me that the rear wheel rotation to get the marks visible in the hole is not the best. My choice, put the bike on the center stand, take the front cover and valve covers off, put a key in the crankshaft, take out the spark plugs, put the bike in neutral and put a brigh light on the inspection hole. Turn the crankshaft slowly with the key until the timing marks appear in the hole, take a small paint brush and some white paint an paint the F, Z and OT marks. Then figure out which cylinder has both valves closed at OT. Adjust it, then 1 full rotation to the next cylinder and do it. You can use a timing light to indicate when the valves open and the F and Z marks will show you that. No?
Anyone use a wooden dowel in a spark plug hole waiting for it to “rise” to get the indicator close? If it doesn’t show up, one more time around.
OM
Anyone use a wooden dowel in a spark plug hole waiting for it to “rise” to get the indicator close? If it doesn’t show up, one more time around.
OM
Make sure it's a long dowel. Lost a stub inside the Gold Star cylinder using that method. Damn, that was a long time ago; my dad was teaching me that method at the time.
Pick up an extra set of chopsticks next time you have a hankering!!
That would be a quick and easy solution/tool. I can’t operate them for anything else.
OM
Right, but it seems to me that the rear wheel rotation to get the marks visible in the hole is not the best. My choice, put the bike on the center stand, take the front cover and valve covers off, put a key in the crankshaft, take out the spark plugs, put the bike in neutral and put a brigh light on the inspection hole. Turn the crankshaft slowly with the key until the timing marks appear in the hole, take a small paint brush and some white paint a paint the F, Z and OT marks. Then figure out which cylinder has both valves closed at OT. Adjust it, then 1 full rotation to the next cylinder and do it. You can use a timing light to indicate when the valves open and the F and Z marks will show you that. No?