No compression

I just did a top-end rebuild on my 03 yz250f. Replaced rings, all five valves incuding seals and a guide, and all gaskets. I put it back together and still no compression. Could it have something to do with the hot start on the exhaust cam?

You may want to check your timing

You may want to check your timing

I have a service manual and I set it exactly how it said to.

I have a service manual and I set it exactly how it said to.

Did you recheck the timing after putting the cam chain tensioner in? If not then it is common to be off one tooth on the intake cam.

Did you recheck the timing after putting the cam chain tensioner in? If not then it is common to be off one tooth on the intake cam.

I did not. Will do though.

I'm not sure if you can see it but the intake cam doesn't line up near as well as the exhaust. If I move it one tooth, the punch hole goes under the top of the head.

http://i1135.photobucket.com/albums/m637/jcwclm/cams001.jpg

http://i1135.photobucket.com/albums/m637/jcwclm/cams001.jpg

It is not uncommon to have the punch dot slightly below the head line of sight on the intake cam with some hours on a cam chain. I didn't see it in your first post, but your cam chain is new right? If the chain is slightly stretched, it is likely that your punch dots will not line exactly up to picture perfect manual specs. I just make sure that that dot on the top of the intake cam is exactly in line with the middle of the tower (yours appears one tick advanced/I can't tell exactly, because of the angle of the camera shot) if the chain has some time on it, which usually results in having the right hand punch mark fall slightly below head line level of sight.

Edited by nokickstandsallowed
It is not uncommon to have the punch dot slightly below the head line of sight on the intake cam with some hours on a cam chain. I didn't see it in your first post, but your cam chain is new right? If the chain is slightly stretched, it is likely that your punch dots will not line exactly up to picture perfect manual specs. I just make sure that that dot on the top of the intake cam is exactly in line with the middle of the tower (yours appears one tick advanced/I can't tell exactly, because of the angle of the camera shot) if the chain has some time on it, which usually results in having the right hand punch mark fall slightly below head line level of sight.

No. It's not new.

its time for a new top end :thumbsup:

Read before you post. It is a new top end.

that was the joke. jeez! ha thats why i put the little laughing guy because you already have one get it? get it? dont be so literal, guy

that was the joke. jeez! ha thats why i put the little laughing guy because you already have one get it? get it? dont be so literal, guy

Ok...........

Do I sense a little squabble or misunderstanding going on here? :confused:

What Happened? :thumbsup: What did I miss?

How many hours do you have on that cam chain? I can guarantee if it's too many, this thread will go from playful joking around to really ending up with what was stated in post #9 becoming a reality.

Take it from someone who doesn't have a top end because of a cam chain problem among others. Yep, that would be me, one brand new head a year for some unapparent reason that still escapes me.

Edited by nokickstandsallowed

Yeah if the dots are off just a **** hair like that then it's no biggie and not the cause of your problems

Yeah if the dots are off just a **** hair like that then it's no biggie and not the cause of your problems

A.K.A. the RCH factor.

Well there's different sizes of c--t hair but could never figure out what was thicker, red or blonde?

Well there's different sizes of c--t hair but could never figure out what was thicker, red or blonde?

Thickness doesn't matter in that particular case, I know which is more fun between the two. :thumbsup: but will definitely settle for both at the same time. What mortal wouldn't?

Dunno I've always lived by the motto "Gotta get it before the hair does"

No no just kidding people!!

I'm thinking of changing my signature that appears at the bottom of my posts. I wonder if I could attach links in there of all my troubles or have an auto link attach feature so as to direct members to my thread links. That way when I state the troubles I am having, I don't have to type up a novel to prove I've had the failures. The copy and paste feature is going to be my new best friend, if my luck doesn't change. :thumbsup:

I think the web site will run out of terabytes before my failures stop. I mean why not, I should just ride around without an air filter, use the wrong gas, use a non-HDEO oil, and regular tap water in my radiator and that should make my bikes top ends' last a little longer. Those are the only things I haven't tried yet; however, doing it the right way has led to shorter valve life - I don't get it?

Oh, I forgot the most important one, I have to ride it at or above 13,000 to keep my motor rippin' good - Yeah, that should make it last longer than what I've been getting out of my top ends that I baby and do preventative maintenance on.

Edited by nokickstandsallowed
Do I sense a little squabble or misunderstanding going on here? :confused:

What Happened? :thumbsup: What did I miss?

How many hours do you have on that cam chain? I can guarantee if it's too many, this thread will go from playful joking around to really ending up with what was stated in post #9 becoming a reality.

Take it from someone who doesn't have a top end because of a cam chain problem among others. Yep, that would be me, one brand new head a year for some unapparent reason that still escapes me.

I'm not exactly sure. I haven't had the bike long.

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