300ex rev box

[300ex boy 22]

I have a 300ex the only mod I have on the engine is an air filter and I don't know what rev box to get and what about the sparks racing rev box eliminater

i owuld get the big gun rev box. it advances the timing i think which adds 1-2 power

[ZSK]

If you're constantly bouncing off of the rev limiter you need to shift sooner. At the rev limiter your engine has already been past its peak performance level. Focus your money otherways first. The only rev box I would put on my quad would be a GT Thunder.:macho

[bwamos]

Originally posted by ZSK
If you're constantly bouncing off of the rev limiter you need to shift sooner. At the rev limiter your engine has already been past its peak performance level. Focus your money otherways first. The only rev box I would put on my quad would be a GT Thunder.:macho

I disagree. The stock 300ex rev limit is very very low. Much lower than any of the other quads out there. I beleive it's right around 7200-7400 rpm stock. You have a LOT of usable rpms beyond that, especialy if you move the powercurve up. Stock the 300ex hits its rev limiter very close to the peak of the curve in stock form.

If you get a top end pipe (like the sparks x-4), a cam, filter, and rejet.. you'll more than likley have your peak power beyond the rev limit.

In stock form, it's not necessary, but even with just a pipe, filter, rejet, and lid removal, it is worth it.

I guarantee you spend a lot of time beyond 7200 rpms on your YFZ, and the 300ex is a smaller bore and stroke, so it will rev even higher if tuned correctly.

Imagine removing 2000 rpms from your YFZ's rev limit.

My 330ex hit's 9000+ rpms regularly.

HOWEVER...

I agree that the silencer, header, and cam need to be changed first before you consider an increased rev limit or timing change.

[ZSK]

A YFZ makes the most power up in the RPM range, it's a given I'm at 7200 if that's where power is made. On a 300ex there's no reason to rev to 9000 UNLESS you have tuned your motor for the upper range RPM power. Usable RPM and extra rev are two different things. 2000 RPM's from my YFZ really wouldn't do much, I rarely come close to the limiter simply because it's set so high.