06 yz250f rebuilt and now wont start

[MudBug20]

Okay guys I just rebuilt my yz after I punched a hole in the oil tank and scared the cylinder. I went with a new all oem yamaha top end. I have gotten the bike all back together and everything is in spec per the manual. I have kicked and kicked and tried pop starting it and i'm getting nothing, but the header is getting warm. The bike sat about a week and a half while waitingon my parts to get here. Timing looks spot on and I didnt check valves shims because it started one kick hot or cold before. Is my thinking right with that or should i still check the valves? I have good spark and comp seems good, am I over looking anything else or anything I can try?

[MudBug20]

i went out and changed the timing 180' and still no change. im pretty sure now my timing is set on the intake stroke and I was correct before. I'm getting pretty frustrated with this and i'm not sure where to go from here. 

[MudBug20]

No help here? I have done some searching and I'm not really coming up with much. I'm going to pick up another plug and some tapered gauges to check the valves.

[SUnruh]

you dont even get a backfire?

 

did you leave a rag in the airbox/airboot/mainfold?

[beezer]

There isn't out 180 on these things.  There is a wasted spark.

[MudBug20]

you dont even get a backfire?did you leave a rag in the airbox/airboot/mainfold?

Every once and a while it will back fire. As for the rag no I don't even have the filter on it right now I thought that Might have been my problem cause it's kinda dirty.

There isn't out 180 on these things. There is a wasted spark.

I mean 180 because I turned both cams 180. I'm not sure what you mean by wasted spark? Like the plug it sparking at the wrong time? Edited September 23, 2013 by MudBug20

[beezer]

The bike sparks every 360 degrees of crank rotation.

[MudBug20]

The bike sparks every 360 degrees of crank rotation.

Okay so does it matter what stroke you set the cams at then? Or just as long as it's at tdc?

[SUnruh]

no it does not matter what stroke.  the plug fires every time the piston comes up

 

if the cams were 180 wrong you may have bent the valves

 

with the flywheel on the capital I mark, the cams should point at 10oclock and 2oclock

 

have you tried holding the throttle wide open for a few kicks (and this is the ONLY time you do this).

[MudBug20]

no it does not matter what stroke. the plug fires every time the piston comes up

if the cams were 180 wrong you may have bent the valves

with the flywheel on the capital I mark, the cams should point at 10oclock and 2oclock

have you tried holding the throttle wide open for a few kicks (and this is the ONLY time you do this).

Okay thank you for clearing up the spark for me, I don't believe I have bent a valve but is there any quick way to check? I did check the clearance on the valves and I think they are to tight.

Edited September 24, 2013 by MudBug20

[beezer]

A compression test will tell you.

[MudBug20]

A compression test will tell you.

I did it and I'm not getting any higher then 60psi. I haven't deactivated the decomp yet either.

[MudBug20]

I have the timing set perfect I'm sure but the intake cam lobe sticks up a little higher the the exhaust cam. Are the lobes supposed to be perfectly parallel to the head like the dots on the cam gears?

Edited September 25, 2013 by MudBug20

[SUnruh]

no!!!

 

that would be 9 and 3 (wrong)

not

10 and 2 (correct)

[MudBug20]

no!!!

that would be 9 and 3 (wrong)

not

10 and 2 (correct)

Okay thanks you are right ill get a pic up tonight of how they are sitting. Is it possible to spin a cam gear?

[beezer]

Do you have an owners manual?

[SUnruh]

Okay thanks you are right ill get a pic up tonight of how they are sitting. Is it possible to spin a cam gear?

 

yes it is possible to spin the cam gear on the camshaft.

 

this tends to happen when you get a cam seizure.

[MudBug20]

Do you have an owners manual?

Yes I have a manual, I replaced everything by the book that's why I'm kinda lost. But like I said I haven't checked clearances yet either I should be able to do that tonight and ill post up the measurements I get off the valves and post up a pic of the back side of the cams. Thanks for sticking with me guys.

[MudBug20]

yes it is possible to spin the cam gear on the camshaft.

this tends to happen when you get a cam seizure.

Okay cams spin nicely on the bearing when they were out so maybe I'm good there. I hope

[MudBug20]

Okay so I checked my valve clearances and the exhaust side is within spec(.20mm .18mm) the intake side was so tight I couldn't fit a .003mm gauge in any of them? I'm at tdc and the timing looks right. I pulled all the intake buckets and they have hc shims in them and they are all 1.20mm. So i'm guessing I need new intake valves?  

Edited September 26, 2013 by MudBug20