Suggestions for a 525 Big Bore kit 540/570??

[Eddie11gt]

Any suggestions on what big bore kit to go with? pros & cons of 540 or 570? How big of a difference from 525? Please help, what should I do and who do you guys recommend to do the work, THUMPER RACING?

[somewon]

I had duncan do my 540 and I've been very happy with all 30 minutes I have on the motor so far.

Heading to the dunes Easter weekend to give it a chance to stretch it's legs.

[evil 525]

who makes the 540 big bore kit

[eerhard09]

If you are spending the $470 on the 540 kit, why not just save a little extra and spend the $670 on the 570 kit? Not being an a-hole, just saying you might as well go all the way if you are going to tear into it. Now doing the stroker is another thing, that gets into serious cash! I would just go 570 since they have not had any reliability issues with it, at least none that I have seen or heard about..... You will probably need a larget case vent though with either one....no big deal!

[smokinwrench]

I was talking to the machinist at my KTM shop about putting a 8/07 cam in and also about porting. He has had a 525 head on teh flow bench and said it flows so good it doesn't need ported until you get to a super big bore over a 610 is what he thought. I also agree if your gonna do it wait a month and get the 570, not sure what the 610 costs.

[eerhard09]

I think the balanced stroker crank is $1300-$1400 just to buy it! Ouch!