Lastly dont be surprised if the 42 pilot jet is to big for a stock pipe and only an aftermarket filter. In my experiance it is. The 40 pilot jet will more than likely be where you end up. 42 is for a pipe and filter and airbox lid removed.
I think you may be right.
When the ATV is cold, I screwed in the throttle adjuster (the hand one) and that seemed to drop the throttle to stall time. I had the throttle adjust screw by the carb screwed all the way in thinking that IF it was the pilot jet that needed to be bigger, that the bike would go from really high RPM to perhaps a normal RPM or even a little high, but it just stalled. My thinking was that the bottom of the throttle wasn't even sitting on the bolt for the throttle stop (with it all the way in, spring 100% compressed). So then I got frustrated and simply adjusted the idle to sound perfect when cold with the hand adjuster and it purred beautifully. I think though it was just not warmed up and it behaves a little different once fully warm.
Today I warmed the quad up, rode it up and down my street 4-5x and really got it ready to go. The idle while idling hot, vs cold is the same. it purrs great. I then tried to reduce the idle speed down using the same hand adjuster, but now that it is warm it seems to not want to sputter and simply just idles beautifully.
I can adjust the hand throttle adjuster all the way down to 0 more threads, then I can use the throttle stop cable (flat-head in it) and I have about 1-2 turns either direction to get it to stall, or idle way too high. This okay?
Using this approach above, I got the idle to go down to a bit above hesitation, but pretty low. I then adjusted the A/F screw in and it doesnt change the idle until the last 1/4-1/3 or so turn before end, which ultimately results in a stall. This leads me to believe the pilot of 42 is prob too large. I do have a 40 I can pop in there, perhaps with the stock exhaust and UNI filter, this isn't enough to justify the 42. It has me wondering too if going from the 138 to 142 was unnecessary. Perhaps the only thing this quad needed was adjusting the idle
Maybe with the 40, i will be able to get it to stall at about 1.5 or so, rather than 0.5-0.0 area.
:EDIT:
I just realized I didnt give the 30 seconds in between. More like 2 seconds. Hmm...
:EDIT#2:
Indeed it makes no difference, 30 second between turns. The MotionPro has 8 total positions, so at 45 degrees a turn, it will still run and sound OK, until my absolute last turn, then stall. So with the time in between, its fine, then 1 last click. stall.
