question for gray racer about shims

3 replies to this topic
  • dewercs

Posted October 25, 2007 - 05:21 PM


i need to buy a shim kit.

1. What manufactuer do you recomend?
2. What size for a yz450f?
3. What size for a yz250f?

Thanks in advance Gray, and disregaurd the PM

Charlie :crazy:

  • 642MX

Posted October 25, 2007 - 05:33 PM


i need to buy a shim kit.

1. What manufactuer do you recomend?
2. What size for a yz450f?
3. What size for a yz250f?

Thanks in advance 642MX, and disregaurd the PM

Charlie :crazy:

1. Hot Cams
2. 9.48mm
3. 7.48mm

I fixed your post too. :D

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  • grayracer513

Posted October 25, 2007 - 07:14 PM


Here's my problem with shim kits.

The big Hot Cams kit has 3 of each size from about 120 to 310 or something for $90. In the first place, you'll never be able to use those shims that are 200 or larger in a YZF of any size. If you shim down to a size more than 3 steps smaller than the original shim, you're begging to drop a valve, so this eliminates the usability of any shim smaller than about 160 or so, all of which means that 2/3 of the kit is useless. This will be especially annoying if you need 4 of the same shim.

Now, you can get "refill" packs that have 5 each of a smaller number of sizes for $35 or so. But since YZ250F's are mostly built with shims in the 175-190 range, and the refill kits split at 180, you'd need two kits.

For a 450, you may never need to shim the valves, anyway. IMO, you should just go to a Honda shop and get the shims you need (they'll almost certainly have them) and leave it at that.

Like the man said, 7.48 diameter for the 250F, 9.48 for the 450.

  • Birdy426

Posted October 25, 2007 - 09:41 PM


As usual, Gray is spot on. If you need to re-shim, just measure, calculate (or use the table in the book) and buy the ones you need. I usually buy 1 up and 1 down from what I think I need, and they end up collecting dust in the toolbox. Many dealers will even swap shims with you if you are a regular customer...

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