I just got this Raptor this weekend and have been researching this forum when I get a chance. Since I'm going on a Colorado ATV trip in a couple of weeks, I will be faced with jetting issues. From what I've been reading it sounds like these motors benefit from mods as well as being tuned or jetted correctly. I've been a 2-stroke dirt bike guy for many years, so I'm very familiar with jetting and reading plugs, realizing it's different on the 4 stroke, but I know I'll be able to rejet this thing.

Last night it hit me...I bought a Wide Band A/F monitor to tune my fuel injected hot rod a couple years ago. I also bought EPROM burning equipment so I wouldn't have to rely on the chip burning aftermarket companies. This A/F monitor is the same setup found on most dynos. My question is...have any of you put your Raptor on a dyno and had it tuned with the help of a Wide Band? Do you know what A/F ratio they were shooting for? On a car, you always tune for 14.7 at idle and low speed, then richen to 12.5 at WOT to make the most hp. I've done lots of tuning and if you're off of 12.5 either way, it makes a huge hp difference. I'm thinking this motor should react the same as a car. I had a bung welded in my exhaust on the car, but I think I can rig the sensor in the end of the pipe. Anybody know if thats the way they do it on the dyno for a 4 wheeler?

This is the link where I bought the setup http://wbo2.com/

Steve

 

I'm pretty sure Dynojet dyno's use a wideband 02 sensor to monitor the A/F ratio with a stinger in the end of the pipe. I think you want lower 13s for WOT and upper 13s for most of the rest, but I could be off a little.