Predator 212 skipping when giving throttle

[Littime420]

Nothing fancy, I have a predator 212 non hemi every thing stock except billet flywheel and gov delete. I bought a genuine mikuni 22mm from go powersports. When i start the motor inhave to give it gas to start. And it wants to take off the second its running. (Its on a cat frame minibike cluth chain and all installed) it will kind of idle on its own but its doesnt stay steady its wants to climb rpms but its like it realizes it kinda cant so it revs down. Its not moving more then 1000 rpms. I have been messing with the jets and I belive my problem is either my pilot jet or something else a lil more major. When I actually go to give it gas it's like it's skipping. Only in the 10% to 40% of the throttle will it do that. Once I get abt half and over it smoothes out. And it like to die. I could try to get a video up if that would help.

 

[Thepaetsguy]

Nothing fancy, I have a predator 212 non hemi every thing stock except billet flywheel and gov delete. I bought a genuine mikuni 22mm from go powersports. When i start the motor inhave to give it gas to start. And it wants to take off the second its running. (Its on a cat frame minibike cluth chain and all installed) it will kind of idle on its own but its doesnt stay steady its wants to climb rpms but its like it realizes it kinda cant so it revs down. Its not moving more then 1000 rpms. I have been messing with the jets and I belive my problem is either my pilot jet or something else a lil more major. When I actually go to give it gas it's like it's skipping. Only in the 10% to 40% of the throttle will it do that. Once I get abt half and over it smoothes out. And it like to die. I could try to get a video up if that would help.

The only real helpful info I can give is to make sure the o-ring is centered on the manifold..

 

[Littime420]

The only real helpful info I can give is to make sure the o-ring is centered on the manifold..
View attachment 312408 View attachment 312409

Are we talk 100% centered shouldn't see a sliver of the o ring. Or is seeing just a sliver ok?

 

[Augiedoggie]

Your carburetor is not sealing. Intake air leak will cause your symptom. Measure carefully to determine o ring can fit over manifold center bore.

 

[SAS289]

So you got a carb from GPS. Do you have the jets in the carb that they recommend in the product description? That would be step one for the carb. You need to have a starting point. You shouldn't have to change jets to be able to start it and work on getting a good idle. And you shouldn't be riding the bike until you get a good idle.

Like others said center the intake to the carb then focus like a laser beam on getting the best engine idle.

 

[Minimichael]

I agree you're probably leaking air, so deal with that first, making sure the o-ring and other gasket to your manifold are flush and sealed. The skipping is likely your engine running too lean, given the presumed excess air is getting in with the fuel/air mix.

At most, you might expect to jet up on the main jet, but very probably not the pilot. Dropping the needle clip to raise the needle one slot might also help your early throttle. But first things first.

I'm no expert, but I've learned the hard way that tuning these carbs — to really get the most out of them — is a multi-step process. And you shouldn't change any jets until you're at a particular step.

The steps, as I understand, are:
1. Mount it, ride it hard and check the plug for rich/lean-ness. Adjust main jet if needed.
2. Set your mixture screw and slide to get your idle right. Ride it hard some more.
3. Adjust needle as needed to affect areas along your throttle range that you wish to boost or diminish.

These two resources might be helpful:
https://affordablegokarts.com/pages/carburetor-tuning

 

[ole4]

Why does it want to take off is motor racing or is your clutch bearing dragging.

 

[panchothedog]

The best ( or easiest ) way to get a good air tight seal between the manifold and the carburetor is to bolt them together with both pieces on the work bench. Where you can look through and manipulate the two parts at the same time. Once you are satisfied, bolt the manifold, with carb attached ( as one piece ) too the cylinder head. Fought the same thing myself. It was a air leak from poor alignment.

 

[SAS289]

I agree you're probably leaking air, so deal with that first, making sure the o-ring and other gasket to your manifold are flush and sealed. The skipping is likely your engine running too lean, given the presumed excess air is getting in with the fuel/air mix.

At most, you might expect to jet up on the main jet, but very probably not the pilot. Dropping the needle clip to raise the needle one slot might also help your early throttle. But first things first.

I'm no expert, but I've learned the hard way that tuning these carbs — to really get the most out of them — is a multi-step process. And you shouldn't change any jets until you're at a particular step.

The steps, as I understand, are:
1. Mount it, ride it hard and check the plug for rich/lean-ness. Adjust main jet if needed.
2. Set your mixture screw and slide to get your idle right. Ride it hard some more.
3. Adjust needle as needed to affect areas along your throttle range that you wish to boost or diminish.

These two resources might be helpful:
https://affordablegokarts.com/pages/carburetor-tuning

I think your step one should be step three. Idle first, then off idle and most of the throttle range. Then change the plug and ride it hard (full throttle) and check the plug for the main jet changes if needed.

I'll see when it gets warmer out. I have a Chikuni that I'm going to put on a stock 196 with a 224 muffler. I want to see how these work.

 

[Minimichael]

It sounds kinda backward, I know, but it's how I read it.

 

[Minimichael]

I guess the theory is that you want the biggest main that best serves you at WOT, and then adjust the others to fall in line under that.

 

[Littime420]

I guess the theory is that you want the biggest main that best serves you at WOT, and then adjust the others to fall in line under that.

So top end throttle is just fine reacts pretty good to quick motions. Another thing that has started to happen as I'm trying to tune it a black suit has built up in the carb. It also leaks out the overflow if I leave the gas line open.

 

[Minimichael]

No more hand holding here

 

[sparkwizard]

Take the carb off, put the stock carb back on. you should be able to ride it this spring.

Learn how the motorcycle carb works before you put it on your bike.
Take the bowl off and learn about how to adjust float level.

 

[JimN]

Nothing fancy, I have a predator 212 non hemi every thing stock except billet flywheel and gov delete.

Hi, welcome. If you don't mind, I have a few questions. If you do mind, I don't mind. If you are able to, post some pics.

Are you still using the stock muffler?
Outside of the generic wanting to go faster, do you have any specific rpm's/mph you're trying to reach?
Compression ratio goal?
What size tires and gear ratio do you have?
What kind of riding do you plan on doing? (offroad/street/race,run around doing wheelies)
Did you crack the crankcase and completely remove the gov.?

At the risk of being called a fanboy/cheerleader, sparkwizard does have a surfeit of common sense and knowledge, you would be wise to pick up what he's putting down.