I was talking to a guy at sparks racing telling me how good these carbs are on the raptor. He was telling me their 686 kit was making about 60hp and with the carbs close to 70hp. Now these carbs arent cheap they cost over 700 dollars.

NoW I am thinking should I go with a 720 kit instead of a 686 kit with some fcr's or what. Please any info would be greatly appreciated.

 

Bikeworx in maynard, mass. has a 2 into 1 kit that is supposed to work very well also. You should look into that as well.

 

I don't know yet, but I will real soon! All I really know is, that after tearing apart the stock carbs, they are absolute JUNK. The carbs alone will be worth it if they just don't cut out on hard landings like the stockers do. That whole vacuum slide thing was dead in the 70's, why would yamaha bring that back?

 

CV Carbs are standard issue on almost every streetbike and ATV since the 90's.

 

NakedRaygun are your K&Ns round or tapered and are they straight or angled? I ordered some Sat. but I don't know if they are going to fit. Also what kind of jetting are you running?

 

Yamaha runs the CV carbs to avoid a lawsuit in the event that a standard carb slide sticks open. It is less prone to getting stuck and it will run with less problems than most any other carb.

For the mild 686 the stock carbs are fine. If you are going with the higher compression piston (12:1) and bigger cam (like Sparks), FCR's may be the way you need to go. IT is true, that there is a good hp gain with the FCR's. BUT the fit of the carbs is poor at best and jetting can be very difficult for those who don't know the carbs. Most of the sets sent out by Sudco have the cable pull on the right side and it will hit the frame unless you shift the carbs to the left. I think Sparks has found a source for the carbs with a center pull to they fit slightly better in the frame.

The question is --- Do you want to spend $700-$900 for two carbs??

On the single carb from Bikeworx, it is great for tight track racing because of the big torque increase in low rpm's. If you are looking for top end hp, you will be very disappointed.

 

I have a single 6" Flanged, Tapered K&N, The Flange is custom built.

 

Is there a website for these two into 1 carbs? How much are they and can you buy a kit to run alky with them?