next question, what is everybodys thoughts on what valve clearance i should be running? i have read thumps post which has em at .003 an .004 i have read others that say .004 an .006 and other up to .008????
yx160 valve clearances
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dynamicgs
Well-Known Member
I go .003 and .004 and mine starts and runs awesome... havent tried any others though, so cant comment on that...
DHZ_XR8cing
Master Spanner Spinner
.003 and .004 without any doubt. Check them when hot aswell.
Done an done. Cheers fellas. Still have a backfire fire issue at idle... Played with the mixture and seemed to make it slightly better (around 3 1/2 turns out) but is still slightly there, at least i know the valves are sweet 
DHZ_XR8cing
Master Spanner Spinner
When things get hot they expand. So this causes the gap to close slightly. Some engines more than others.
sean01
Legend Spanner Spinner
your .008 might actually be .08 which is mm's
3 & 4 seems to be the sweet spot on most, big cams can go slightly bigger. roller rockers could go slightly tighter but set em hot or at least re- check them when hot.
eichkay
Well-Known Member
Is that a china thing ? I think someones taking the piss
Ive never heard people checking them when hot before ... how hot ? 60ºc 40ºc ? 85-90ºc at running temps ?
Once you have all the tools out the motors cooled down anyways and theres no way in hell your checking the head at a realistic temp above 75ºc even if you superman quick you gunna burn the hell out of yourself ... then your doing the exhaust side its now cooled down 20-25ºc more than the inlet you just did hows that going to effect everything ?
Checking when hot is the stupidest thing ive ever heard..
DHZ_XR8cing
Master Spanner Spinner
Its good advice and is been done by more people than you might know. Could give you a slight advantage over your competitor.
You can take my advice of leave it. No skin off my pickle
sean01
Legend Spanner Spinner
its the way its spose to be done.. more so for older style engines tho.. china engines i class as older lol..
being an engine reconditioner/mechanic it was the standard in doing rockers.. everything these day are hydraulic tho..
being an engine reconditioner/mechanic it was the standard in doing rockers.. everything these day are hydraulic tho..
eichkay
Well-Known Member
more the thing is how hot is it really once you've got the bike apart enough to do these checks ? its no longer anywhere near the 75ºc + the bike will be running at.. i race rc cars and check electric motor temps all the time, there is no way in hell anyones hand is going to near 60ºc+ for more than a few seconds never mind resting there hand off the manifold while pulling back the feel gauge to check for a bit of drag.
You'd be better off checking the motor "cold" in a hot shed in the peak of summer at least the everything is going to be constant 50ºc rather than a cooling down motor at luke warm at 35-45ºc once youve done both sides
sean01
Legend Spanner Spinner
have you never heard of mechanics using kevlar gloves...
i personally check rockers hot and cold, mostly hot tho and i manage to do it bare handed..
heat doesnt drop very quick on engines, infact it probly raises before it drops.
go sus out a service manual for an earlier mazda or nissan engine, they should list 2 separate rocker clearances for hot and cold conditions...
now more to the fact here, it seems cause you've never heard of this you think it's a crock of poo... quite the opposite my friend..
dyno tuners will set rocker at different settings between dyno runs.. on an engine already reaching near max its hp potential more hp can be found by setting them to what the engine likes.. might only be 2 or so hp but it all counts..
i personally check rockers hot and cold, mostly hot tho and i manage to do it bare handed..
heat doesnt drop very quick on engines, infact it probly raises before it drops.
go sus out a service manual for an earlier mazda or nissan engine, they should list 2 separate rocker clearances for hot and cold conditions...
now more to the fact here, it seems cause you've never heard of this you think it's a crock of poo... quite the opposite my friend..
dyno tuners will set rocker at different settings between dyno runs.. on an engine already reaching near max its hp potential more hp can be found by setting them to what the engine likes.. might only be 2 or so hp but it all counts..
