Xr 70 Valve Adjustment Procedure

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Oct 9, 2007
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#1
I just got a honda 1999 xr-70r for the little brother the guy that we brought it off said all it need was the valves adjusted now i was just wondering how we could adjust the valves to get it working again the bike starts arfter a bit of effort trying to roll start it and when its warm it fires up arfter kicking does this sound rite?? it has also had the rings and piston replaced not long ago 3-4 mounths ago

so if anyone knows or has some sort of idea on how to adjust the valves any help would be appreciated

cheers jordo
 

junkjeeps

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#2
You need to line up the timing marks on the flywheel and cam sprocket and have the piston at TDC(top dead center). From there adjust both intake and exhaust to .002" +/- .001"(I see you're from across the pond. I'm not sure what the MM conversion is). If your timing marks don't line up just right, check the timing chain for slack. It's not adjustable, you'll need a new one.
 

Jasle

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#4
junkjeeps said:
You need to line up the timing marks on the flywheel and cam sprocket and have the piston at TDC(top dead center). From there adjust both intake and exhaust to .002" +/- .001"(I see you're from across the pond. I'm not sure what the MM conversion is). If your timing marks don't line up just right, check the timing chain for slack. It's not adjustable, you'll need a new one.

.002" seems awfully tight for the exhaust valve of an air cooled bike. i've never looked them up but I'd figure the exhaust would be for sure larger than the intake???
 

Patman

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#5
Yup .002-.003 I believe is the correct range. Yes a .002 feeler gauge tears easily :)