2008 Crf 450r bearing out or what? I'm lost.

KylerCrf450

KylerCrf450

Ok, I've been taking a long time. But the delays have been from not having the right tools. Does anybody know what size of valve shims I should get?
 
2Wheels

2Wheels

Ah that little calculation may require a bit more understanding than can be related in a forum post. You may want to research some fundamentals about what exactly you are attempting.
Short answer is, the distance between the cam lobe and the valve bucket at top dead center must have a certain amount of clearance listed as specification in the manual. .015mm-.20mm for example. The shim you need will fill this gap appropriately as tested with slight drag of a feeler gauge. Measure the clearance you have versus the clearance you need to have, and size your shim accordingly. Now if you ask what is top dead center I'm calling motorcycle protection services on you to take it away to a foster home
 
SRAD97750

SRAD97750

Moderator
Staff member
2Wheels:
Ah that little calculation may require a bit more understanding than can be related in a forum post. You may want to research some fundamentals about what exactly you are attempting.
Short answer is, the distance between the cam lobe and the valve bucket at top dead center must have a certain amount of clearance listed as specification in the manual. .015mm-.20mm for example. The shim you need will fill this gap appropriately as tested with slight drag of a feeler gauge. Measure the clearance you have versus the clearance you need to have, and size your shim accordingly. Now if you ask what is top dead center I'm calling motorcycle protection services on you to take it away to a foster home
Click to expand...
Textbook :thumb:
'Measured Clearance' minus the 'Desired Clearance' added to the 'Current Shim Thickness' is the shim you buy.
(MC-DC)+CST=New Shim Thickness
Example:
You measure 0.15mm clearance (MC)
Spec clearance is 0.20mm (DC)
Current shim is 2.45mm

(-0.05mm)+2.45mm=2.40mm shim
-BIG DAN :thumb:
 
KylerCrf450

KylerCrf450

Yeah, it might be best if I bought to a shop and have them find me the right shim. I was studying about it and it sounds pretty important to have the right size.
Do you guys think it's possible that all that metal in the motor was caused from one of the shims falling into the motor? Because I know that when I took it apart. I don't remember seeing all 4 of the shims.
 
PALMER84ONE

PALMER84ONE

Probably would not start/run without a shim. if one was lost, it was from before. If the shim fell in, it would rip the gears apart as its hardened like the gears.
 
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