cylinder head reconditioned..cylinder head and cylinder gasket 400's

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  • 5valve

Posted March 19, 2008 - 01:20 PM


Have a '99 WR.
Got cylinder head gasket and cylinder gasket off ebay, ment for YZ 400 '98.

Part numbers are:
5[COLOR="Red"]GR[/COLOR]-11181-00-00 for head
5B[COLOR="Red"]F[/COLOR]-11351-00-00 for cylinder.

But for '99 WR are:
5[COLOR="SeaGreen"]BE[/COLOR]-11181-00-00 for head
5B[COLOR="SeaGreen"]E[/COLOR]-11351-00-00 for cylinder.

Visually can't distinguish head gasket diffrences, but with cylinder gasket, there is a thickness diffrence...WR measuring 1.1 mm or 0,043 inch and YZF measuring 0,6 mm or 0,023 inch.
What can I expect with thinner gasket..higher comppression or piston hitting valve. Cyl and head codes WR and YZ also differ slightly.

Second thing, more like a job well done is fine tuning the head.
Reconditioning valve seats and valves and also head surface leveling.
Yamaha uses only two angles on the seat, I have now three angles and also angles are diffrent for better flow.
Valves are suited, to fit the angle of course.

This is 9 years old head, first valves, everything in spec, only valves were a bit leaky, so I was loosing a bit compression and that was probably reason for a bit higher oil drainage from head vent tube and quick oil contamination.
Since I also have reconditioned cylinder, presume I'll ride quality now.

Posted Image

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