Runaway bike

[Preduhtor_122]

So I have a stage 2 predator on a Coleman BT200x. For a carb I’m using a 22mm Mikuni. I’m having problems with starting the bike. I can’t start it unless I give it a lot of gas on the throttle. And two. A lot of the times the bike will already be running once I start the engine. This has cause the bike to completely take off on me and launch out from under me. The bike has a torque converter with a juggernaut So y’all can imagaine how hard it flys out from underneath me. No idea what’s wrong. Is the throttle cable getting stuck? Is the carb not tuned right? I’m completely lost here. I’m thinking about switching back to the original carb with the .038 performance jet but the Mikuni cost me 120 from go power sports so I really don’t wanna just throw that money away

 

[Brianator]

First things first! Your carb slide should be cracked open so there's about a 1mm gap (at it's widest) when the throttle is at rest (idle), this is a good baseline for the idle setting.

It does though sound to me like you need to tune the pilot circuit to suit your motor, the question is does it need to be richer or leaner...? One sure fire way to find out would be to figure out if it starts easier with the choke open or closed? It's sure to start easier one way or the other so if it starts easier with the choke closed it would indicate to me that you would want to enrich the pilot circuit and of it starts easier with the choke open then you'd want to lean the pilot circuit. This MAY be accomplished with the mixture screw and if not then you'll need a different jet then tune it in with the mixture screw.

Plenty of fellas here have successfully set up 22mm Mikunis so worry not, you'll get it and learn along the way!

 

[Preduhtor_122]

It starts easier with the choke off. With the choke on it takes a couple of pulls to get started.

 

[Brianator]

Confirm your idle gap then open the mixture screw IF needed. Should be an "air screw" on that carb so opening it will lean it. Always make small adjustments (looking at it like a clock face make 1-2 hour adjustments) and wait 20 seconds for it to take effect if the engine is running.

 

[Preduhtor_122]

Also. If I run it full throttle for over llike maybe 30 seconds. The engine starts bogging out and then it dies. And afterwards is a pain to get it to start again

Is the Mikuni giving the engine to much gas causing the engine to flood?

 

[Brianator]

Not sure yet but kind of sounds like it. You need to tune that carb starting with the idle circuit, then you tune the midrange then the main jet. If you do it any other way you'll either get lucky or be chasing your own tail going crazy! Lol

 

[Preduhtor_122]

I removed the chain to the rear sprocket just so I can work on it without it running off. It starts up fine but then the Rpms start spiking up rapidly. They’ll go up engage the torque converter. Then go down and back up over and over. Could this issue be a dirty or clogged carburetor?

 

[jonlasaga]

Hey Im having the same issue as you with my predator swapped yl2. Mine has a bouncy idle of some kind though as well to go along with it and sometimes it just goes full throttle for whatever reason. Do you have the legit mikuni or the chinese one?