01WR426 small end rod galling...

WR/YZ 426F Weirdness...Help?

I just pulled my 01wr426 apart to send Eric Gore my cylinder for the O.S. bore connection.

Surprise, surprise when I got the head off.

The center intake valve has been clipping the edge of the piston cutout leaving a shiny rolled corner on the piston...

The small end of the rod is also starting to gall.

The piston pin is definetly toasted.

The book says .016-.039" freeplay at this junction.

This appears to be a misprint.

I would personally set it up at .0015-.002"...It is at .0015"...This is actual measured clearance, the manual is a bit ambiguous here. It doesn't call out how they are applying their dimensioning to reality.

I hate designers...Just give me a drawing I will make it.

Has anyone seen these symtoms/problems on a stock bike?

Any insight would be considered.

[This message has been edited by SFO (edited 06-10-2001).]


What were the symptoms, sounds that made you liik into it?


It wasn't making any noises...

I disassembled it to get a Gore big bore.

Look at what I found.

Kinda hard to warranty something that I took apart.

Or that has no symptoms.

I am just seeing what I see.

I will certainly clay it upon reassembly.

The wrist pin also took the brunt of the galling.

I believe a new wrist pin and a light ball honing is going to straiten that out.

I was curious if there was a history of rod problems on this motor.

[This message has been edited by SFO (edited 06-13-2001).]

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