i have been looking around at some different kits and i am wondering what companies do you all recomend? i also plan on doing something with the head, but im not sure yet, any recommenendations would be helpfull.
thanks jeff

 

I like JE. I've had 3 JE pistons and never had any problems out of them. You can gain a lot of power out of the head by installing a cam, port job, and bigger valves from Kibblewhite. You will probably need a high compression piston before you get too crazy with the head.

 

mine is bored to a 686 was i great way more power also if u are looking for a exhaust i would get yoshimura off road it sounds sick those are my to top engine mods i also jetted and tons more

 

JE is junk for the 660R, at least the 100-102mm 10.75:1 pistons.

Hard to beat Wiseco for "bang for the buck" but if you want something other than an 11:1 CR you should look at Ross or CP. CP is probably the best choice from a performance standpoint.

11:1 is the highest compression that you can run at or near sea level on premium pump gas, anything higher requires straight race fuel or a pump/race mix.

The hotcams stage 2 is probably the most popular cam for a 686 build and for most it's also the best. If you want a little more low end power instead of top end you go with the stage 1 hotcam. The stage 2 will require upgraded valve springs.

There are almost as many ways to port a head as there are places and people willing to do it. IMO it's best to have a trusted name do the work, a place that has documented experience making power with the 660R, not just some guy in his garage who knows how to hold a dremel.

If you've got the money the best thing to do is to send it off to a respected engine builder. There are a number around but the most popular are Kenz Cycle Tech and Craycraft Racing. Both do an excellent job and can build your bike to your needs and your budget. Kenz has a website with contact information, kenzcycletech.com, and if you search around you should be able to find craycraft racing's phone number.

 

Why is JE junk? I had been thinking about getting one for mine. Is there something I need to know?

 

This is the forum where the JE problems were exposed, over and over again. Long story short they break, usually right near the top of the piston. Now it's not happening on every 660R running that piston size/compression configuration but it's way too widespread and common to ignore IMO. This has been a problem for the 660R for years and is one of the reasons why Ross and CP found such a quick following with the engine builders, the pump gas JE's weren't reliable enough.

Spend a little time searching the old threads, you'll find quite a few and pictures that highlight the experiences.

I like JE, they make great products. But the 100-102mm 10.75:1 pistons they make for the 660R are the exception to the norm.

 

Thanks, that's a good piece of info!