Re: Best motor Build for 660
firstraptor said:
673 and be able to bore the cylinder another 1mm later. I think more is gained by the compression bump than the added bore size.
You might also look up Tim Barker, I think I read he's offering a +6 stroker.
This is the philosophy I had in mind when I decided to make my bike a stock bore buildup. The 2hp that'd be gained by the 2mm jump in bore size wasn't as important to me at the time as the ability to rebuild. However I already owned the 100mm piston when I started the rebuild so my choice was easier to make. I'm actually on my 3rd set of rings on the same wiseco 100mm piston and oem cylinder. That said, my next project is likely to include the 10:1 105mm piston I have lying around on a stock stroke.
If you're willing to spend the money on a new crank and rod then I'd suggest the ever popular 720 HR kit. If you're putting up the money for a rod and piston you might as well increase your displacement while you're at it. If you want to sneak in under the $$$ wire on an oem rod then I'd stick to a mild 686.
Personally I'm not quite as paranoid as some (ie: much of BT) about rod failures. They do happen and they are costly but IMO it's not necessary to replace them just because you break 53rwhp. A lot of it has to do with setup, maintenance and tuning as well. But if you can afford it and have any inkling of breaking into the 65 hp and up range now or in the future then I'd suggest doing it now rather than later.
The cam chain should be replaced often, especially if you run at higher rpms. I throw a new one in once a year because of their questionable reliability when it comes to stretching and breaking. The main bearing on the other side of the crank is a 30-40 dollar part alone, I've never looked into any kind of full engine kit.