Carb Trouble ?

[Pete7072]

Guys, as you know, I had to rebuild the top end of my Warrior motor. Everything is together, and there is no smoke. It idles fine, but is having a hard time at high revving. The bike doesn't want to stay at high RPMs. The carb was stripped down, soaked, cleaned and put back together correctly. It's an aftermarket Mikuni carb. Fuel or Ignition? Thanks

EDIT : It's more like it's misfiring more then anything else. Start riding it and then "BAM" almost fall off the bike, then it continues going.

 

[DeadLastRacing]

Hows the carb boot? Is it ripped to torn?

 

[Pete7072]

Hows the carb boot? Is it ripped to torn?

No it doesn't appear to be sucking air in at all. Everything is good there. The parking brake is also disconnected. I'm thinking the carb is jetted to high. Idles fine, just starts to pop misfire and sputter at higher RPMs. I'm hoping it's not the CDI, or electrical problem.

 

[Pete7072]

The bike idles fine, we just re-jetted the carb, it's running fine. The only problem is that it's still missing. WE've narrowed it down to the ignition system. Just trying to figure out if the CDI or Stator would do this. Or coil?

EDIT : I'm leaning towards CDI or Stator. The plug is turning black fast. And with the new top end there is no smoke at all anymore. Also the parking brake has been disconnected.

 

[DeadLastRacing]

To rich if you've got a black plug. What jets you running and what filter and exhaust setup do you have? Rule out the Stator and Coil by ohm metering them.

 

[Pete7072]

To rich if you've got a black plug. What jets you running and what filter and exhaust setup do you have? Rule out the Stator and Coil by ohm metering them.

Do you know where I can get the correct voltage for the stator and coil ? - Disregard I found the OHM for all the coils, just looking for the Stator

 

['00 WO-YA!]

Dude, mine's been doing the same thing since I changed the head on it, exactly like you're describing. Runs fine @ idle but when it gets into the high revs it breaks down & runs like ass! It ran this way once before when I played with jetting & got it too rich but I've jEtted down & changed the needle setting to no avail. I'm leaning towards ignition myself & have a good spare stator to try but I've been too lazy to do it.

 

[Pete7072]

MY friend doing my warrior, worked for Yamaha, and now has his own shop. He's amazing with any type of ATV/Dirbike. I call him the mad scientist. We lowered the jet on the carb ( aftermarket Mikuni ) and still nothing. Seems like it's running rich, but it back firing and pop out of no where has us down to the ignition not sending spark at sometimes.

 

['00 WO-YA!]

Yup, mines doin that too man, feels like all ignition just drops out for a split second but it does it repeatedly & w/o rythem, just poor running.

 

[Pete7072]

Yup, mines doin that too man, feels like all ignition just drops out for a split second but it does it repeatedly & w/o rythem, just poor running.

Hopefully DeadLast will post.... He's another mad scientist. This is why I post on this site, and ask for their advice.....

 

[Pete7072]

It also had a White Brothers slip on, and a White brothers Filter. Tried running it with no air gox cover, but its still doing it which led me to the ignition.

 

[Pete7072]

Just sprayed CARB cleaner into the boot leading to the carb, the bike cut out. The boot looks fine, maybe it's the Gasket. I bought a Brand new CDI, and it didn't do anything.

 

[MidwayUSA]

Sometimes the fasteners get over tighted and warp up the mounting surface. Pull it off and run it on some sand paper and see it it is flat. If not sand till it is. I always use a thin film of RTV just to be safe. I have had Blaster and Banshee cages and intake boots be warped from over tightening and the vacuum leak there can be devastating on a two stroke.

 

[Pete7072]

Sometimes the fasteners get over tighted and warp up the mounting surface. Pull it off and run it on some sand paper and see it it is flat. If not sand till it is. I always use a thin film of RTV just to be safe. I have had Blaster and Banshee cages and intake boots be warped from over tightening and the vacuum leak there can be devastating on a two stroke.

Yeah, It's from the Carb to the Head. We sprayed it and it bogged down and stalled. It runs great even with it suck air. I just bought a CDI too for this bike. $150 and travel time, just to find out that my bikes CDI is fine.

 

[MidwayUSA]

Pretty sure there is no gasket, but o-rings. I had mine off this spring but I don't remember.

Edit: I just looked at a parts blow up. There is an o-ring on the carb where it meets the intake tube, then there is an o-ring on the intake tube side that meets the head. Just need to sand all the surfaces till flat. Even though there are o-rings, I still would use a thin film of RTV. Don't glob it on too thick. Just a thin film to help seal it up.

 

[Pete7072]

Pretty sure there is no gasket, but o-rings. I had mine off this spring but I don't remember.

Edit: I just looked at a parts blow up. There is an o-ring on the carb where it meets the intake tube, then there is an o-ring on the intake tube side that meets the head. Just need to sand all the surfaces till flat. Even though there are o-rings, I still would use a thin film of RTV. Don't glob it on too thick. Just a thin film to help seal it up.

Bike runs and idles fine, but there is still that " Hic-UP" at idle and full throttle. The pic is where it's sucking air in. Very small leak.

 

[MidwayUSA]

Is that an OEM carb? Pic is kind of hard to see clearly. My 02 the intake tube bolts to the head with two studs and nuts then the carb bolts to the tube. That appears to be a clamp on and I am not familiar with whether that may be OEM on an earlier year or not. Someone else may have to chime in on that.

 

['00 WO-YA!]

That doesn't look stock, I agree it's hard to see but still don't look stock to me.

 

[Pete7072]

No, It's not stock, it's an aftermarket Mikuni Carb, We can't find model numbers on it at all, even when we stripped it down. Previous owner didn't have the paper work for the carb. Bike came with the title, manual, and all Yamaha stuff from the factory that was switched with Aftermarket except the carb....

 

[duneracerweston]

Looks like mine but yours has a different intake boot setup I dont think that that boot looks right to me it looks.like the rubber is coming off the alum. Butaybe thats just me