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Old 05-07-2010, 06:41 AM
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Default 2008 yz125 - milling the head

Newbee here,

I was told that "IF" the head is milled .010, the jet needs to go up to the next size. Has anyone got any experience on this?

Also, what octane would be best suited for this modification?

Just gathering future info.
Thanks in advance
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Old 05-07-2010, 08:15 AM
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More than likely, you will need to jet up for that mod. As far as fuel goes, 93 octane will still be good for that but 100 octane race fuel would be better. You will have to play with the jetting to get it spot on depending on your elevation and temp your riding in.
What are you trying to get out of this mod, if you don't mind me asking?
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Old 05-08-2010, 06:35 AM
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Talking

As of today, I'm very happy with our yz125.

Just wondering what would give us a little more easy HP. We race this engine in a Winged Outlaw Kart. The Honda's we race against aren't too close to us, but there is a yz250F we want to beat. It has a TON of power off the corners. We are soooo very close to it, yet so far away.

I think "IF" we had just a tad off the corners we could pass underneith it, maybe.

I was thinking:
New reeds
torque plate
mill head .010
race gas

something easy to do, yet give us some more umphhh.
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Old 05-27-2010, 09:29 AM
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.010 isnt all that much, but may be the max you can go without some reshaping of the squish band on that one. you can play with base gaskets to get the same thing, with a little more midrange thrown in since the thinner base gasket will retard the ports a bit.

what types of race gas are legal in that organization? if you go to VP's website you may find some fuels that will help you with the compression issue and give you a bit more response too.
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