426 valve springs


3 replies to this topic
  • stroker yz426

Posted March 11, 2008 - 09:02 AM

#1

have found a good deal on a used set of springs that have 5 hrs on the head rebuild, so i decided i should purchase them, i only paid 11.00 bucks, they are oem, which is fine with me, but he said that they wont work with stainless valves, but the are for bikes with the titanium valves, my engine is a 00 426, and has stainless from the factory, but i have only found one part number from yamaha for each style spring in the tt store, why is this, the 01 and later are supposed to have ti valves aren't they, this is starting to be a pain, so i figured id go where the knowledge flows like water, to the tt wedsite and ask the people who really know, so if anyone knows why im having this problem, or if that these springs wont work with stainless valves, please hit me up

thanks guys:worthy:

  • Speedracer747-400

Posted March 11, 2008 - 09:31 AM

#2

The 00 YZ426F uses stainless steel valves and the 01-02 YZ426F uses titanium valves. Since stainless steel valves are heavier than titanium they require a stiffer valve spring. If you use weaker valve springs that were meant to be used with titanium valves on your stainless steel valves you will get valve float. If you get valve float at high rpm and the piston kisses the valves your engine will be garbage. I would stick to Yamaha OEM parts when it comes to the valve train. Why would you buy used parts for $11 when you can get brand new for $15.62?
While you have it apart I would also recommend replacing the timing chain.

2000 YZ426F valve springs

(3EA)5BE-12113-00-00 SPRING, VALVE $2.84
(2EA)5GR-12114-00-00 SPRING, VALVE $3.55

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  • grayracer513

Posted March 11, 2008 - 09:40 AM

#3

The 2000 YZ426 valve springs are:

Intake: 5BE-12113-00-00 (3)
Exhaust: 5GR-12114-00-00 (2)

These are the same as the 1999 YZ400 springs. TT OEM has them both listed in the parts catalog for the 2000 YZ426 for about $3 each, so I'm a little puzzled as to why you are so confused, but regardless, they or any Yamaha dealer can fix this for you.

2001 models used 5JG-12113-00-00 and 5JG-12114-00-00, and should not be used with SS valves.

  • stroker yz426

Posted March 11, 2008 - 10:56 AM

#4

thanks guys





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