Is my cylinder junk?

2 replies to this topic

Posted May 14, 2013 - 02:47 PM


Hello, I have a 05 yz450f it started smoking real bad.
i took it apart to do the top end and i assume this wear at the top is through the plating and the cylinder is bad, but im sure.

Also because my bike was smoking real bad what can i look for in the head to make sure its not coming in through there and not the rings. I would hate to just do a new cylinder piston and rings and it continue to smoke because i over looked the head?

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  • grayracer513

Posted May 14, 2013 - 02:53 PM


The only way the head could be involved is via the valve guide seals or the head gasket, unless there's a crack someplace, which isn't very likely.

The cylinder appears to have significant wear, but without precisely measuring it, you can't really know. The pictures don't definitely show the plating being worn through, but if it is, you will normally see it as a distinctly grayer look tan the rest of the bore. There's nothing that I can see that would prevent that bore from being replated.


Posted May 14, 2013 - 03:41 PM


thank you.

ill probably send it out then and see what can be done.
Any recommendations on places to send it I'm in northern ca

if I sent my head out would they inspect that stuff or should my local yamaha shop be fully capable of inspecting it.

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