I plan on installing one this weekend. Anyone have any pointers for this procedure? Thanks.

You might have to rejet.

How do you install it? Any special tools?

Thanks,
Dan

I had the local Yamaha dealer put mine in. I know you need a 3 prong puller to get the side open, but other than that i'm not sure. I didn't have to rejet and I am not totally sure about how much it helped because I put on a taller front sprocker at the same time. I also spoke with Sparks and they said there should be no need to rejet.

Gary660r: My advice is DON'T do it. It's a semi-pain-in-the-@ss, and I didn't feel like there were any appreciable benefits. I promptly took mine back out. It may have even initiated (don't ask me how) the famous stalls-on-the-top-end problem that so many of you have read about from me on some of my posts. I was not impressed, and will not do it again on my new Raptor when I get it. Good luck, whatever you end up doing, but I'm not convinced.

No benefit on a built 660.
Slight benefit in low end on a stocker.

I would not recommend this product.

I don't know about not getting anything from it on a built engine. I was looking at that Vitos or Vinnies(The guy who builds those special blaster and banshee pistons) website and he had the Horsepower charts on a built engine and he showed before and after charts with his advance key(5 degree) and it showed a strong 2 HP increase. However those are two strokes.

2 strokes and the 660 are two different animals. Waste your money if you want. I have made the dyno runs and I know it is a waste of $$