valve adjustment....


4 replies to this topic
  • Leelandc

Posted March 02, 2007 - 03:08 PM

#1

I am just wondering what you have to do if everytime you check your valves, they need to be adjusted. Does that mean to need a new top end, or do you have to buy new valves?..how much would all this cost...How often should a bike like the 426 go before it should be adjusted?
Also what happens to a bike if you drive it for too long with the valves not properly adjusted?

  • grayracer513

Posted March 02, 2007 - 03:10 PM

#2

What year 426?

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  • Leelandc

Posted March 02, 2007 - 03:33 PM

#3

its a 2001

  • 642MX

Posted March 02, 2007 - 04:26 PM

#4

I am just wondering what you have to do if everytime you check your valves, they need to be adjusted. Does that mean to need a new top end, or do you have to buy new valves?..how much would all this cost...How often should a bike like the 426 go before it should be adjusted?
Also what happens to a bike if you drive it for too long with the valves not properly adjusted?


When Ti valves get tight within a few hours of use it means they are shot and need replaced. Buy some new valves, springs and valve seals. Have a local machine shop touch up the valve seats before you rebuild the head. While your at it throw in a new piston, rings, and cam chain.

  • grayracer513

Posted March 02, 2007 - 04:26 PM

#5

That engine has Titanium valves. Normally, from the time they are first assembled, they will go for years without needing a valve adjustment. Then, eventually, the thin coating of titanium nitride that makes them hard wears through, and they start wearing very quickly. Once any one valve has gone to the point where the shim it needs to be at the proper clearance is more than .10mm smaller the what was there to start with, it's time to replace the valves.

Letting them go introduces the risk of dropping a valve head due to stem flexing caused by a worn valve face scrubbing sideways on the seat as it closes.

426 owners do have the option of using the stainless steel valves and matching springs from a 2000 model. These are less expensive and even more durable than the OEM ti valves are.





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