New Engine has no thrust

GoKartNarc

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Hi everyone, So my problem is this:
I have a new to 212cc Predator engine on a Mega Moto mini bike. I removed the governor, replaced the stock lash spring's with 18lb ones, found top dead center and reset the lash valves. 5000th on the intake and 7000th on the exaust. So after everything was complete it started up, but when I hit the throttle I noticed there was no torque. It would not move forward. When I crank the throttle all the way it just sputters. It seems like it wants to go, but the engine is not cranking at its full potential. When I removed the spark plug it was completely black on the end. I did also go back into the engine and find TDC and readjusted the lash valves, hoping it would solve the problem, but it did not. Is there something wrong with the pistons? Thanx
Note: I've modified the 212cc Predator engines this same way before and never had a problem like this.
 

GoKartNarc

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Yes the throttle is hooked up correctly. I even manually moved the lever and it didn't make it difference. And yes that was the recommend it lash gaps. I did the same thing on my other Predator engine and did not have a problem.
 

jamyers

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Is this a New from the store or new to you engine?

Black spark plug indicates either too rich a mixture, or an ignition misfire. I'd double check the ignition coil, it should be something like .018-.020 gap between it and the flywheel magnets (better look that up for sure, my memory ain't what it used to be). Then take a CLOSE look at the spark plug wire and boot, should be no cracks in the insulation, and the end should click solidly onto the spark plug. Check the plug gap, and clean that sooty one up.

Then look at the carburetor - how did it run before you swapped valve springs, etc?
 

GoKartNarc

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Unfortunately I can't post a video because it's making it too complicated. I can say that it does start right up, and then when I hold the throttle down it's sputters and a lot of smoke comes out of the exaust. I'm sure there's something wrong with the pistons. When I pull the spark plug it's completely black on the end. I don't know where to start and what to look for with the pistons.
 

GoKartNarc

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Is this a New from the store or new to you engine?

Black spark plug indicates either too rich a mixture, or an ignition misfire. I'd double check the ignition coil, it should be something like .018-.020 gap between it and the flywheel magnets (better look that up for sure, my memory ain't what it used to be). Then take a CLOSE look at the spark plug wire and boot, should be no cracks in the insulation, and the end should click solidly onto the spark plug. Check the plug gap, and clean that sooty one up.

Then look at the carburetor - how did it run before you swapped valve springs, etc?
It is a brand new engine and I've done the same to other engines that were new and never had this problem. I will check the gap on the spark plug and go from there, thanx
 

mckutzy

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Pics of your setup...

What is the gear ratio?
What is the OD of the rear tire?
Gov out(completely?)
Stock carb or modified(rejet or different type)?
Clutch or CVT?

Stock con-rod???
 

mckutzy

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Internet vernacular for-bring up my post...

As in the questions I had asked.... What about them...

Pics of your setup...

What is the gear ratio?
What is the OD of the rear tire?
Gov out(completely?)
Stock carb or modified(rejet or different type)?
Clutch or CVT?

Stock con-rod???
 

GoKartNarc

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Internet vernacular for-bring up my post...

As in the questions I had asked.... What about them...

Pics of your setup...

What is the gear ratio?
What is the OD of the rear tire?
Gov out(completely?)
Stock carb or modified(rejet or different type)?
Clutch or CVT?

Stock con-rod???
OK what I can tell you is that I don't know that gear ratio or the OD of the rear tire. The gov is removed, stage one kit for the carb and jet, it has a torque converter and stock con-rod. Could it possibly be the jet?
 

karl

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Could it possibly be the jet?
Maybe

I don't know the gear ratio or the OD of the rear tire.
Id look into that. Even if the jetting is slightly too rich, with an inadequate gear ratio, your bike will never be right.
And all three details matter , front sprocket, rear, and tire size. Only part of info= partial awnser.

Anyway, how does it run with the rear tire in the air, no load?

What happens if you slightly choke it? Huff worse?
 

GoKartNarc

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Maybe


Id look into that. Even if the jetting is slightly too rich, with an inadequate gear ratio, your bike will never be right.
And all three details matter , front sprocket, rear, and tire size. Only part of info= partial awnser.

Anyway, how does it run with the rear tire in the air, no load?

What happens if you slightly choke it? Huff worse?
These are all good questions. I will go home and tinker with it and see what I can find. How do I find out the gear ratio?
 
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