predator 212cc mid range problems

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mikeholt25

New Member
#1
#1
ok I have built another 212cc I have got a aluminum flywheel on it haven't put rod or nothing in it just have removed the Gov. and have installed a gx390 carb but before I put the gx390 carb on there I had this issue I got now.


when Im at a dead stop in I floor it its takes of pretty good but after that its like its dragging a car in bogs down an shakes bad in then it picks up again straightens out an halls ass down the road. Its not the clutch slipping either its just like I said its like its trying to pull a car

could this b the 8 degree timing flywheel to much timing to I need to buy a 2 degree key in time it back or not enough fuel. Or do I need to back off the timing but it did this with the factory carb. also I have open air filter in a j pipe on it coil gap is at 40/50 I really cant remember is this a timing issue
 
M

mikeholt25

New Member
#3
#3
no I do not because it delivers more airflow in on my other 212 it made it a totally differ motor doesn't matter which carb u got as long as air in fuel mixture is good then you should b fine in I like these carbs that's why. but it had this issue with the (FACTORY) carb.
 
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rmm727

Active Member
#4
#4
If you had the stock carb, I would say it was an e tube issue. In other words, I would have tried the 140 e tube. Could just be a jetting issue. I can't imagine that a basically stock engine needs a bigger carb.
 
Prowler08

Prowler08

New Member
#6
#6
Can't see it being a timing issue unless it slipped.
If it did it with the stock carb sounds more like your idle jet is too small.
In Kart racing this is the reason we run a .024-.028 idle jet.
Sounds like in the midrange it is having a fuel issue, a bigger idle jet will help this transition from low to high jet and get rid of the issue at midrange.

Not too sure about the 390 carb though...but we have no problems getting 17+hp out of a stock bored carb. Jetted right, we start out with a stock etube, .024 low jet and a .038 high.and tune from there.
This is on gas.
 
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M

mikeholt25

New Member
#8
#8
I have the ar3910x plug on a 14cc head can you use that plug with that head iv noticed my shim on the plug isn't there so could this b my problem.
 
SnakePliscan

SnakePliscan

New Member
#10
#10
8 degrees of seperation

If the motor is going lean throgh the mid-range and its advanced 8 degrees its gona burn off the feul sooner and kill the power worse than if you were running less timing, the fact that when it gets on the main and it gos good kinda tells ya its coming from a bad place and now its happy. timing is fine feed the fire in the mid.
 
boostdoctor

boostdoctor

New Member
#11
#11
I had a similar problem with my gx160 chopper, and it was the clutch. It took off fine and then shook like crazy as the clutched locked up. Once the clutch locked up, it smoothed out. It shook so bad that it broke the spokes in the back wheel. This was with a Noram clutch. I replaced it with a Fury and the problem went away. I don't really think its the carb if the factory one did the same thing.
 
SnakePliscan

SnakePliscan

New Member
#12
#12
Intake and pipe mod

So were are you on the idle screw?

Does opening up the idle screw make it less responsive off idle but slightly better in the mid?
These carbs from the factory are on the ragged edge of lean as mandated by EPA.
If you change anything,.. just the pipe and filter, that will throw it off i would think.
 
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mikeholt25

New Member
#14
#14
thanks boostdoctor it was the clutch I turned around in watch the clutch in the midrange damn clutch smoking like crazy then when it locked up it hauled ass shakes the hell out of the kart I figured it would of sounded like it was slipping in raced the motor up like it would a car damn these little engines act way differ then cars lol
 
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