shims are missing??

[WB450r]

so this past weekn i replaced a head gasket on my 450..i put everything back to normal tightened all the bolts to spec etc..cranked it up at the track let it warm up for 5 to 10 min, rode it around in the pit area for a couple min then cut it off to check for leaks..no leaks..5 min later i got all geared up and went out on the track..quad rode like **** so then i pulled the top of the head off and the 2 shims that go under the rocker arm by the cam are missing..anybody ever had this problem and what could've caused this??

thanks

[d3ktrix]

Did u remove the cam tower from the head when u did the work?
Forget to put them back in? Cam tower cocked on the head when u put it back on leaving a large gap over the exhaust shims?

[SHIFTx450]

Man that sucks. Whoever was responsible for putting the cam cradle back on f'd up.

Something was left loose it sounds like, from the fact the bike was running fine for a bit as stated.

You're gonna have to tear the bottom end apart to find them shims.

Do NOT crank that thing over in any way until you find those shims. Hopefully they didn't cause much damage.

[ss440ex]

If they both are missing, I would pull your stator cover and check behind the flywheel area.
Also remove the gasket off the stator cover and look in the cover itself!
I have seen them fall down in behind the cover and hide.
Good luck!

[bsmith106]

I've had the shims stick to the rocker when both were covered in oil when installing a cam. This was on a crf250 so a bit different .the rocker picked it up and flung it down the the timing chain hole. Had to pull side cover off to get it out.