hi, i recently put a mikuni tm36-68 flat slide carb on my warrior. it is jetted fine except for the pilot circuit. the pilot circuit was rich, i turned the screw in at idle and the revs increased and kept increasing until the the screw was all the way in. the jet that came in it was a 30, it came with 27.5 and 32.5 extras, so i put in the 27.5. same thing, screw went all the way in. went and bought 25 and 22.5, same thing with both of those. i'm getting tired of taking my carb off and changing jets, is there something i'm doing wrong or some other problem? or should i just keep trying leaner jets?

I'll take a couple shots.

1) Idle too high (throttle plate to far open) causing you to pull from the fuel circuit other than the idle circuit.
2) Fuel level in bowl too high causing you to pull from the fuel circuit other than the idle circuit.
3) Clogged air bleed causing you to pull from the fuel circuit other than the idle circuit.

Then again, my background is more automotive, but no one else had answered. Time for me to get some more research material.

thanks, um what exactly do you mean by air bleed? one thing that's funny is that the white brother's kit that this came in gave it a 30 pilot, but upon internet research i have found that the same carb from a few different other places gives it a 12.5 pilot with the same 130 main, i need to open the top to see if the needle is the same. I'm thinking i should probably try the 12.5, i'm confused as to why white brothers would put such a big pilot in it.

Again this is from an auto background.
The idle fuel circuit uses the vacuum on the backside of the throttle plate to pull fuel into the air stream. The main fuel circuit uses the vacuum from the air flowing though the carb (venturi effect). The idle ciruit shuts off when you open the throttle due to loss of vacuum at the throttle plate. The problem lays in the fact that any time you have air flowing through the carb you have a vacuum signal to the main fuel circuit. Buy using an air bleed in the main fuel circuit, the vacuum signal pulls a small amount of air instead of fuel while idling (this is how the main fuel circuit shuts off). If this air bleed were to be clogged, it would allow the carb to pull fuel from the main fuel circuit while at idle. Even if not clogged, this can also become a problem with highly modded engines that require more airflow to maintain an idle. The increased airflow will turn on the main fuel circuit at idle. I don't know how built your engine is, and again an ATV carb could likely be well removed from an auto carb. The basics should be the same though. (Anybody recommend a good book on motorcycle style carbs?)

ya, ATV/motorcycle carbs are a bit different than a car's, i'm pretty sure there is no air bleed as you've described. The pilot (low speed) circuit is activated when the throttle plate is closed due to vaccum, and when the throttle plate is opened the jet needle/main jet circuit come into play, and i'm pretty sure that's it besides the acclerator pump. i'm thinking i have to try out that 12.5 pilot that comes with all the other tm36-68s, just sucks cause the place to get jets is a good hour away from my place, and i hope they take back the wrong jets that i bought from them, i dont see why not, a jet is a jet, it's a non-moving part and it was only in the bike for an hour.

I have found reference to the air bleeds as a pilot air jet (appears to control when the idle curcuit shuts off around 1/4 throttle), a main air jet (plugged on most, would only have an effect when the main is on at 3/4 throttle and above), and just an "air jet" reference too. It appears that main fuel circuit turn on is controlled by the needle pulling up out of the needle jet. I found some good reference, probably not your exact carb, but well worth looking at.

HSR

VM manual

Mikuni hs40

I seem to have it figured out, i went to the shop and the smallest pilot jet they had was a 15 so i took it, put it in, and the peak idle revs are at 1.5 turns out on the pilot screw, prefect! And it seems to have a little more guts too, response is better and the back end spins out that much easier. Thanks for you help COTU