The mikuni 42mm carb? is that the BSR 42mm mikuni carb found on the ds650? if so its kinda a weird carb i would stay away from it....although there are a crap load of mods you can do to it.

 

thanks for the reply. Well I eventually wanna put the Athena big bore & hotcams for the intake & exhaust. Thats probly about it besides the K&N velocity intake kit. Don't think I will get it stroked out cuz Idon't even know what that means.
I was actually calling around today different retailers in the magazine & talked to one dude named Chad, he was real cool. He also also told me that the kehin FCR carb the bike already has is really good & don't really need to upgrade my carb even if I installed the big bore kit. You agree with that?

Anyhow so which exhaust? the ron wood, fmf factory 4 or now I was even thinkin the Team Alba pipe???

 

Well actually I am getting the info on it at rotax.net for the Ron Wood kit. its called the "TM Mikuni 42mm" carb. Im not sure now though, cuz I shifting towards to just keeping the stock keihn carb. Everyone's sayin its a actually a really nice carb. I was only thinkin about getting the mikuni cuz I might have gone with the Ron Wood pipe. Now Im thinkin about either the fmf factory 4 system or the Team Alba pipe with the stock carb???

 

The FCR Keihein is a top notch carb and works excellent with bolt on mods. I don't have a heavily built motor, but if I did, I would probably go with what my engine builder was recommending. Stick with it for now and see if it needs upgrading later? As for the pipe, I only have any experience with HMF, which I am highly satisfied with. Performance, design, finish, and cust. service are all top notch. I only have heard good about the Ron Woods pipes, they might be more of a top end pipe though? I wanted a good boost throughout the powerband. Check one of the YFZ specific forums, I know there are a few guys running that pipe.