Coleman CT20u-ex Built Predator 224

#1
I have a Predator 224 with flattop piston, billet rod, hot 275 cam, 28lb springs, champion rockers, billet flywheel. VM22 carb with 150 jet. at full throttle it seems to need more fuel and the bowl runs dry. do I need to raise the gas tank or install a pump? Coleman ct200u-ex
 
#3
round slide Vm22 the motor shuts down. when i get off the bike i can see the air bubble in the line and I hva to wait for the bowl to fill again before it will start back up.
 
#4
how were you able to tell that the bowl runs dry? What carb do you have? there are a few completely different VM22 carbs. Is it a VM22 round slide with the jet in the bowl or a Chikuni with the oval slide?
round slide Vm22 the motor shuts down. when i get off the bike i can see the air bubble in the line and I have to wait for the bowl to fill again before it will start back up.
 
#14
Stock fuel tank to the motor
It might be too low.
Try this, put a container under the carb to catch fuel, Crack open the drain screw on carb. Might have to open it 3 or 4 turns.
If no fuel comes out, but you have fuel in tank, try putting more fuel in tank and see where the level is in tank, when it stops draining.
If it empties the tank , then it's not a fuel level problem.
 
#15
Tank may be too low. Need a picture of it otherwise we are all just guessing. Also a 150 Jet is too big unless it is using pwk jets. That is not your problem however. What manifold are you using to mount the carb to the head?
 
#16
Tank may be too low. Need a picture of it otherwise we are all just guessing. Also a 150 Jet is too big unless it is using pwk jets. That is not your problem however. What manifold are you using to mount the carb to the head?
I only have one bad angled picture. With the main jet at 150 its not blowing black smoke, and my sparkplug is still a light white color.
 

Attachments

SAS289

Well-Known Member
#19
I don't know that's what trying to figure out.
I think his point is the air in the fuel line.

I have zero experience with a Mikuni on a minibike. But I would be checking fuel flow with and without the filter. And not using so much fuel line. I would also be looking for an air leak at the manifold. Probably the first thing to check.

Another thing to consider is how do others get away with a Mikuni with the stock fuel tank? And how many use that large of a jet? From what others have reported you should be able to start with and run well with a 130 jet.

Another thought is what gearing are you using? Are you even getting to an RPM that may drain the bowl?
 
Last edited:
#20
I only have one bad angled picture. With the main jet at 150 its not blowing black smoke, and my sparkplug is still a light white color.
when is it not blowing black smoke? When you blip the throttle? The main jet is only in play from 3/4 throttle to full throttle. The rest of the time it does nothing unless it is so small it cant pass enough fuel to affect mid throttle. Unless you do a full throttle run then chop the engine ignition the plug color is more a reflection of your pilot, air adjuster, and needle position.
 
Top