Help with valves

[Judge]

I done the valve clearance at .003 .004 I started it it run well let get hot then checked the clearance again they had to be adjusted again to 3 an 4 then when I tryed to Start it an it would not start like it had not much compression do u have to check them when it's hot or is it ok to set them when it cold an leave them it's a 155z motor

 

[timeeh]

.003 and .004 when cold, you can check them when hot too, but the measurement changes, i can't remeber to what though.

 

[Judge]

Yeah sweet wat I mean is do they have to be check when it's hot or don't it matter cause the bike was running fine till I checked it when it was hit re adjusted it then it wouldn't start so should I do it when it's cold an don't bother checking then when it's hot

 

[nickv1980]

do them cold because when the bike heats up the clearances change with expansion of the metals

 

[Judge]

Ok cool do it cold an don't check them when it's hot

 

[my67xr]

correct,
do it with the engine cold, then leave them set at that.

 

[Judge]

Thanks mate much appriceated

 

[DHZ_XR8cing]

I do mine hot.
What they are cold means nothing.
We dont ride our bikes with cold engines do we??

 

[my67xr]

here is the how to video from OO Racing,
slightly different clearance settings, but it still explains it well
http://www.youtube.com/watch?v=QJciyJRJh8Q

 

[nickv1980]

your right we don't ...... but the .003 .004 is a cold clearance setting not hot so if your adjusting it to that spec hot there not right .

Obviously you can set em hot but the clearance setting would be different I'm sure it would be easy to look up on the web but I'm to hung over n lazy right now lol

 

[motodevo]

I do mine hot.
What they are cold means nothing.
We dont ride our bikes with cold engines do we??

You're supposed to do them cold, the .003/.004 clearances take into account the expansion of parts when they heat up, the exhaust getting more heat hence needing more clearance. Plus its a more consistant baseline for clearance as everyone has a different idea of warm, idling for 5 mins, ridden for 5 minutes or full on thrashed wot for half an hour will all be different. Setting them when warm means you may have no clearance when cold, ie hard to start/not getting full compression.

 

[zwebx]

if you really be spot on get a temp gauge... get it up to a certain temp... set the clearances at 0.001 and then keep it in that temp range for perfect performance...

it would be interesting... get it hot et them to 0.00000000 and then measure them when there cold

 

[Judge]

Yeah I've look on the web an I carnt find anythink . I've set them but some times it's like it's got no compression but it still start my nephew set them but I'm mint sure wats wrong its never been like this till he set them wat do u think it would be

 

[pete88p]

hey guys.. i know this sounds like a newb question... but do i have to drain the oil to check the clearance on my valves? or should i be fine? i just want to know exactly what will happen when i pull the tappet covers off i donot want a oil mess all over my garage floor... plz send some info my ways fellas.. thanks

 

[timeeh]

^You'll be fine, you may loose a couple of mil but nothing to stress over

 

[zwebx]

Setting them when warm means you may have no clearance when cold, ie hard to start/not getting full compression.

wrong way around.. because when it gets cold then the clearances go to .003 or somthing because the valves have shrunk down to there original size
if you set them to 0.00000000 when cold then you would loose compression when warm and prolly smack a valve when really hot

 

[motodevo]

whoops, didnt even pick that up when i wrote it

 

[DHZ_XR8cing]

You're supposed to do them cold, the .003/.004 clearances take into account the expansion of parts when they heat up, the exhaust getting more heat hence needing more clearance. Plus its a more consistant baseline for clearance as everyone has a different idea of warm, idling for 5 mins, ridden for 5 minutes or full on thrashed wot for half an hour will all be different. Setting them when warm means you may have no clearance when cold, ie hard to start/not getting full compression.

This is a personal way I do it that I have found to be best. I'm not saying this is how its meant to be done.
It actually works the opposite. When cold the gap is bigger then when hot.
I set mine cold then check them hot to see the variable. Every engine will be different taking into account type of oil used and how often its changed, type and amount of oil coolers, riding conditions and duration.
I have had engines that don't change from .003 and .004 hot or cold and other engines that the clearances halved on either or both valves. Its about knowing your engine and setting it up individually.