TDC mark
 

I have a Tank Trail 200 with the OHC 163FML just like this one:
http://www.chinariders.net/modules.p...adjustment+ohc

and I want to check the valve clearances, but there is no "T" mark on the flywheel. All I see is an arrow, then two unmarked lines, and then an "F" mark which feels like it should be TDC. It looks like the "T" mark in the picture but it's an "F". At this "F" mark i can move the valves up and down a slight bit. Anyone else have these marks? I don't want to set them at the wrong spot.

Also, my manual says to do .05mm for both intake and exhaust, but it's for the pushrod engine. I've heard .05mm intake and .08mm exhaust for the OHC. Can anyone confirm this? Thanks

Specs aside, all overhead valve engines should have valves set at TDC. To confirm TDC, the rockers should be able to wiggle a bit. They would not have any movement if the rockers were pressing down on the valves even slightly. Use that as a guide.

As usual, W&G has offered superb advice. :) If you can wiggle the rocker arms, you are at TDC, or close enough. ;) To confirm, rotate the flywheel another 360 degrees, counterclockwise. The wiggle room should disappear, indicating you are now on the exhaust stroke. Rotate another 360 degrees, counterclockwise, back to TDC, and the wiggle room should reappear. You are now ready to adjust your valve clearance. :D

Spud :)

any idea what the "F" stands for?

The F stands for Fire. That is where you want to set the spark timing at idle. Usually about 10 degrees before TDC. Generally the two unmarked lines are the spark advance marks.

Q

BTW, using the F mark to set the valves should be close enough since both valves should be fully closed at that point on the compression stroke. You could also pull the spark plug and put a pencil in the hole to see when the piston reaches the top.

Q

I always use a pencil or something similar to check TDC. Pull the spark plug and insert the pencil, it will rest on top of the piston. Rotate the engine and the pencil should rise or fall. TDC is when the pencil is almost out of the hole. Check the marks on the flywheel to see which is TDC. It's probably 'F' as stated previously.