HELP! Minibike Predator 224 Revs high wanting to take off on start and dies off choke...??

#1
I've very recently bought the Predator 224cc wanting to put it on my Minibike. Also buying a VM22 Carb and header for the 224 installing both. And mounting the engine on to the minibike. I should mention that I checked the Carb just incase it was dirty for some reason also changing the jet with a bigger one. Full Governor removed Aswell. But when I started it up the bike literally took off reving high... since I was now wary of that happening I put the bike on a stand so it wouldn't take off. I started the bike up again same thing happened but obviously didn't take off because it was on a stand. I let it warm up a little then tried to lower the idle speed on the Carb but to no real success the wheel was still spinning like someone was throttling the bike. I also should mention that at this time I didn't have the trottle cable connected... I tried tuning the whole Carb over and over to no success. I looked for vacuum leaks (none), Changed main jet and tuned Carb (no success), checked gas and lines (nothing wrong) oil check (nothing wrong). Checked spark (is fine). Can somebody please help me..?
 
#4
Obviously later on I will get internals and a flywheel setup but for right now I just want to get the engine at a smooth base running point.
 

Triley41395

Well-Known Member
#6
Listen everyone here likes helping with problems others are having, most likely somebody here has had the same problem your having. Removing or zipping the governor with out the correct parts is just a bad idea. If you get the correct parts for a build there's always someone willing to help talk you through installing and helping tune it. Mini's are cool and a lot of fun but nobody wants to help you blow up your motor or worse get hurt. I'm telling you this because I don't want you to think that this site is full of jerks, it's not but they do believe if it's worth doing its worth doing right and safely.
 
#8
Like I said obviously i will get the right parts or "safety parts" because i don't want to engine to blow. Right now I actually have a fresh billet rod, flywheel and cam on the way. I have other parts at my place to help to such as springs, etc. But rn I think it's a carb problem and I'm not very knowledgeable of carb just asking for tips and suggestions which can help me in my current state until everything comes in and I setup it up. Also I appreciate it for responding and help me.
 

SAS289

Well-Known Member
#9
Have you removed the filter and had a look at the position of the round slide? Is it hung up open or something? I don't know how with the spring they use but it's something worth checking.
 

Steve73

Active Member
#10
Like I said obviously i will get the right parts or "safety parts" because i don't want to engine to blow. Right now I actually have a fresh billet rod, flywheel and cam on the way. I have other parts at my place to help to such as springs, etc. But rn I think it's a carb problem and I'm not very knowledgeable of carb just asking for tips and suggestions which can help me in my current state until everything comes in and I setup it up. Also I appreciate it for responding and help me.
take your air filter off and see what the slide looks like. is it all the way down? is it hung up some how? needle position right? things to think about... I know you can figure it out eventually..
 
#12
take your air filter off and see what the slide looks like. is it all the way down? is it hung up some how? needle position right? things to think about... I know you can figure it out eventually..
So I looked at the slide and it was all the way down the whole time and doesn't get hung up / stuck. Also I've tried all variations 1-5 of needle positions lean, medium to rich and no real difference at least to the back wheel spinning at high rpm..
 
#14
What size slow jet? Can you kill the engine with the air screw at least? If you can only run with the choke on, the main jet doesn't matter at this point. These carbs have like five separate systems inside and you sorta have to learn each one on its own. And did you say the throttle cable is not hooked up? This manual helped me a lot.
 

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#16
what does “see is if the choketurns off” mean? A mikuni vm22 (chikuni?) does not have a choke, it has a enrichment device which has a fixed jet and air bypass around the slide. If the slide is all the way down that is one problem. But if you are starting it with the enrichment on do not try to adjust anything till it warms up a minute with enrichment on. Then turn off enrichment. If slide is all the way down it should stall. Slide should be raised off closed about .060 and initial idle mix screw about 1.5 turns out from closed. Use idle slide height adjuster to set slide height. Needle has no effect on idle.
 
#17
what does “see is if the choketurns off” mean? A mikuni vm22 (chikuni?) does not have a choke, it has a enrichment device which has a fixed jet and air bypass around the slide. If the slide is all the way down that is one problem. But if you are starting it with the enrichment on do not try to adjust anything till it warms up a minute with enrichment on. Then turn off enrichment. If slide is all the way down it should stall. Slide should be raised off closed about .060 and initial idle mix screw about 1.5 turns out from closed. Use idle slide height adjuster to set slide height. Needle has no effect on idle.
In terms when I start the bike with enrichment on I let it warm up and for good amount of time. Once the engine is warm I try to adjust the carb which seems to have no effect on the engines idle. Obviously when I try to turn the enrichment off the engine stalls. I've looked inside at the slide to see how far the slide is raised off.
 
#20
Once warm then you adjust running or not. did you check the slide open height? did you set fuel mix adjuster? Once warm it should try to start. you can raise slide more but it may rev high and turn out mix adj. What values are your pilot jet and main jet?
 
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