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Motorcycle Repair/82 honda xr 80 dirt bike


im haven a real hard time tryn 2 time this honda xr 80 i put a whole new top end on it. new carb. it a little cream puff but need help timing the thing and also what is the gap suppose to be between the vavle and the rocker arm  im thinkn its .008" but not sure i still have to adjust the vavles and timen

Andrew, When you put the timing chain back on, the piston needed to be at TDC (T mark on flywheel) and the cam lobes downwards so both valves are closed. There are marks on the camshaft sprocket that would align either with being parallel with the cylinder head or a single punch mark that would be at 12 o'clock position.

If you didn't get the camtiming set perfectly, then there is a chance that you can bend the valves when the piston hits the valves due to being out of synch.

Valve clearances, as noted in the above links is .002" when both valves are closed on TDC compression stroke.

Bill Silver

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Bill Silver


Need help with vintage Hondas from the 1960s? I am an expert with 250-305cc bikes in particular and most all of the other pre-91 models, in general. I do NOT claim to have a great deal of experience on Gold Wings, Cruisers, ATC/ATVs and dirt bikes.


I have owned/ridden/maintained Honda motorcycles for 35 years. I have written five books on Honda repairs and collecting. I was a service manager for two Honda shops back in the 1980s.

VJMC (Vintage Japanese Motorcycle Club) of North America

VJMC newsletter, as editor for two years and as contributing editor currently.

3 years auto shop in high school, teacher's aide in Automotive Technology in Jr. College, Diesel mechanic course in college, self-taught mechanic and automotive writer.

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