Valves off by a mile! What do you think?

[Codynetz634]

Just bought my 07 trx450er maybe a month ago. It has been hard to start sense I had it but once started run good. I decided to check the valves because I believe that was the culprit. I think I'm right. But here's what I measured...

Front of quad

O O
.50mm .48mm

O O
.11mm. .04mm

Rear of quad
The circles are what valves follow the diagram on where the exhaust and intakes valves would be. I also used this very well explained DIY http://www.garyhott.com/valves.html I have also adjusted valves multiple times on 400ex. This is the first on a 450r. Is it normal to be this far off from spec? Thanks in advance!

[CJM]

If the quad has alot of hours on it chances are the valves are no good and need to be replaced as they wear into the head. Thus you may need a valve job if you cant get the right specs with shims.

This is right out of the service manual.

Intake is
.16mm +/- .03mm or .006in +/- .001in

Exhaust is
.28mm +/- .03mm or .011in +/- .001in

If you have a manual decompressor (looks like the 400ex valve adjusters)
Right side exhaust clearance +.25mm +/- .02mm or .10in +/- .001in

To figure out new shim size:
A= (B-C) + D
A= new shim thickness
B= recorded valve clearance
C= Specified valve clearance
D= old shim thickness

[Codynetz634]

Thanks for all that info. Really helped! But I did the adjustment everything is within spec. But now it will not start. I'm for sure getting spark. All I get is a pop once in a while our of the exhaust. What do you think that could be? The right intake valve is still a bit tight but not far off. Maybe .04 off and it ran before anyways. Oh and the timing is all correct.

[CJM]

Sure its getting fuel?

Try bump starting it, it starts then its def the valves needing more adjusting or replacement.

[Codynetz634]

Okay I'll have to do that in the morning. Thanks again!

[Codynetz634]

It will not pop start and it has a loud tapping sound when it tries to to turn over while attempting to pop start.

[CJM]

Sounds to me like soemthing is off, hard to tell without physically looking at it tho.

Are you sure your valves are in spec? They maybe too tight now.

[Codynetz634]

Okay got another update for ya. I now have no compression. I even took the decompressor screw out but still zero. Does this mean I have a valve stuck open or maybe I need more adjustment? I don't understand why it ran before because the valves were even tighter then. Thanks for all of your help!

[Codynetz634]

I also tried a leak down test with no leaks. What am I missing?

[CJM]

Check your timing and then double check the valve adjustment.

[Codynetz634]

okay I now feel like a big dummy :huh I used the wrong mark to align the timing after I went to reset it after swapping out the shims. there is a smaller dot and an actual hole on the gear down where you align it on the crank. I was using the hole and not the dot. which it was very hard to see with oil on it. I guess ill see if it fires up tomorrow after I go buy a spark plug. im sure it will because I actually have compression!

[CJM]

Bingo!

[Codynetz634]

Fired up right away! I guess everyone makes mistakes. Actually an easy one to make right there. Anyways thank you very much for the input!

[CJM]

Quite welcome. Glad you got it fixed :)

[DnB_racing]

Okay got another update for ya. I now have no compression. I even took the decompressor screw out but still zero. Does this mean I have a valve stuck open or maybe I need more adjustment? I don't understand why it ran before because the valves were even tighter then. Thanks for all of your help!make sure the cam tower is not overly tight and evenly torqued,
I've seen the decompression arm stick from one side being torqued down un even


EDIT :::: I guess I should have kept reading before I posted LOL

glad you got it

[CJM]

Still good advice DnB!

[Codynetz634]

Still good advice DnB!

You're all good! I appreciate the input and advice anyways!