tri-z250 idle problems

[Tri-Z Pilot]

Whenever I start up my tri-z with the choke on it takes off on a very high idle almost as if the throttle was stuck wide open but isnt(have checked numerous times). If you leave the choke on the engine will keep revving and overheat,and the only way to shut the engine down is to turn the choke off which almost immediatly kills the engine. You can even pull the spark plug cap off and the engine will continue to run(how is this possible)? When I pull the spark plug out and look at it it has no signs of preignition, alittle sign of overheating, but thats to be expected from idling so high. My exhaust gasket leaks a little but I dont think that is the problem, I have checked for air leaks but found nothing. The engine is bored .10 over and I am running a mikuni vm 32mm roundslide carb which has a 470 main, #45 pilot, 2.0 air jet, 159 q-6 needle jet, 6dp17 jet needle, 3.0 throttle slide, pilot air screw 1.0 turns out, with a uni pod filter, the exhaust is also stock. If somebody could plese tell me why this is happening it would be greatly appreciated Tri-zs Rule!

[badtriz]

very thoroughly clean the carb, completely disassemble it, and check the reeds. but before all that, check the idle screw to make sure its not screwed in very far. if its not that, maybe check the choke lever and see if something is not right there.

[trikeman]

it sounds to me like you are dieseling, do the same as badtriz said, make sure you have a quick smoothe flow of gas too, it diesels because the engine is starving for gas.


~Rich

[Tri-Z Pilot]

It couldnt be a dirty carb its brand new. but ive seen a couple posts of some guys saying they run a 3.3 motorcycle needle valve. I run a 1.5 on mine because I thought you had to for fuel pump assisted engines. Could this be the problem, also my idle air screw is at 1.0 turns out.
Also, when I tried starting it today, I put the mixture screw at about 2.0 turns out, and tried starting it with the choke off and it backfired. I then tried it with the the choke on and the engine idled roughly for a couple of seconds then took of on a high pitch rev again, I had to put my hands around the uni filter to shut it off. when ever the engine does get a chance to idle slower it seems to be rich because there is a good amount of black smoke that comes from my leaky exhaust gasket.














be

[Tri-Z Pilot]

Could an upside down float be the problem.

[Tri-Z Pilot]

I took my carb of just to ckeck a couple of things out and when I got to the float bowl the float assembly just didnt look right. I think I may have put the float arm upside down, would this make my bike act the way it is?

[Tri-Z Pilot]

I just got to thinking today, and you know what? I think I forgot to put clamps on my impulse line to my fuel pump. I whent out and checked my impulse line for the fuel pump, and guess what, no clamps. Could the line going to the fuel pump stave the carb for gas, and in turn make the engine diesel?