Bike has a Dynojet stage III kit in it and I've taken the needles up and down, with them now raised TWO FULL CLIPS above the Dynojet recommended initial settings. This surprised me that they'd need them raised so high (only one clip higher is left!), but this setting has minimized the width of the band where she spits at partial throttle and massively reduced the spitting compared to other settings. No amount of fiddling with the mixture screw has helped this poor midrange/partial throttle performance.
I had a good conversation with "Mike" at Dynojet last night and it sure sounds like the man knows his stuff. He said it's unusual to need the needles that high, but not unheard of for this motor, and I might even need them up to the top notch. (sigh of relief)
His main recommendation was to go ahead and install the smaller pilot air jets which are recommended as "optional" in the Dynojet kit instructions. I had these in earlier before raising the needles, but they didn't help anything so I took them out. The smaller air jets should richen the pilot circuit up throughout the band, unlike the mixture screws which really work down low. With this, I should be able to adjust the mixture screws to "best idle" and not need to enrichen them to try and fatten the midrange mixture.
Two interesting notes: Mike told me that the Dynojet air screws are sized identically with the Mikuni air jet sizes, unlike the Dynojet fuel jets where numbers don't correlate with Mikuni jets. Also, the purpose of drilling out the air hole in the vacuum slide is to increase the rate at which the slide can rise and fall, increasing throttle response. I was speculating on this in another thread, so now we know.
I have some new socket head screws on order since the JIS phillips heads are getting all beat up, so I'll probably wait to make the mods suggested by Dynojet. The main point of this post is to let folks know that if you're having troubles like this with Dynojet kits, 1) the recommended settings aren't gospel and 2) the folks there are knowledgeable and helpful if you need to speak with them.
Will report back on results.
Comment