Hey everyone. Just had a question, hopefully someone has an idea on what is going on. I have an '05 Yamaha Raptor 660R SE. I recently installed a full system HMF Sport Series exhaust system and a UNI filter. I jetted the carbs exactly as specified on the manufacturer's website (150 left/155 right), 3 turns out on air-fuel mixture screw and needle clips on 3rd position. The machine runs EXCELLENT... fast as all hell, snappy, lots of bottom, mid and top end. My problem is, ever since I did the upgrades, the bike has a tendency to stall when coming to a stop (with the clutch pulled in). Doesn't do it every time, but every once and a while, I'll be in 1st gear getting ready to stop, I'll pull the clutch in and about a second or so afterwards the bike stalls. It fires right back up no problem, just don't understand what's making this happen. Only thing I can think of is maybe the air-fuel mixture screw needs to be adjusted? If I remember correctly stock it was 2.5 turns out, and HMF recommended 3 turns out (which it is now). Any advice would be GREATLY appreciated.

~~CHaD

 

Curtis Sparks recommends installing a larger pilot jet on the 660 when adding a pipe. I think 27.5 is the correct size.