Predator 212 Valve Noise????

[sparkwizard]

If your float level is off, your tuning efforts will be a waste of time. Get the level correct, adjust the idle and then see how it runs.
Keep in mind, you are building a one of a kind engine. As such, you are the designer, builder and tuner. We are here to help with some advice, but you are the one who is learning and actually solving each and every issue. Never get frustrated or lost. Sit back and think about how it is SUPPOSED to work. Maybe even go read a book about whatever it is, absorb what you need, then think about why your engine is not acting the way it is supposed to act. Ask questions. Enjoy your holiday!

 

[Thepaetsguy]

If your idle mixture adjustment makes no difference, I would check float level. If your fuel is too deep in the bowl, it will be rich at idle.
As your RPMs go up, your fuel level goes down as your fuel flow can't keep up. I think you have three problems.
1. float level holding fuel too deep in bowl.
2. Fuel delivery to the carb not keeping up with demand.
3. After you take care of those two, then fine tune with your needle position.
I am no Mikuni expert, I have a bunch of tractors.

I’m no Mikuni expert either but for the most part you shouldn’t take the bowl off the china ones unless they leak. there is an o-ring that sets in a valley in the bowl and it’s a pain to get the bowl on with the gasket and get the o-ring to line up/push through the hole in the gasket and seat into the valley in the bowl. the o-ring grabs the gasket and gets everything all out of wack and it drips.. I have a vm22 bolted straight to the blocks of two 8hp engines with no manifold. at WOT for very very extended periods it can sometimes suck the bowls dry I highly highly doubt op is dealing with that. I did not touch them besides unwrapping them and bolting them on they make awesome endless power and I wouldn’t dare try to tune them.

 

[tylershg]

I’m no Mikuni expert either but for the most part you shouldn’t take the bowl off the china ones unless they leak. there is an o-ring that sets in a valley in the bowl and it’s a pain to get the bowl on with the gasket and get the o-ring to line up/push through the hole in the gasket and seat into the valley in the bowl. the o-ring grabs the gasket and gets everything all out of wack and it drips.. I have a vm22 bolted straight to the blocks of two 8hp engines with no manifold. at WOT for very very extended periods it can sometimes suck the bowls dry I highly highly doubt op is dealing with that. I did not touch them besides unwrapping them and bolting them on they make awesome endless power and I wouldn’t dare try to tune them.

I mean I have to tune it to make I run properly. I mean I haven't had any issue with it leaking or having any trouble seating it

 

[Thepaetsguy]

I mean I have to tune it to make I run properly. I mean I haven't had any issue with it leaking or having any trouble seating it

you have a 212cc I have 304cc’s.. You say the you pulled the spark plug and it looks like it is running rich. your running a 120 jet? I‘ll go check the hour meter but I know the last time it read above 10 hours of seat time. I have the stock 90 jet in all the 304’s with upgraded springs carb/header torque converters etc.. i’m only after speed. I run a 14t t/q sprocket and 60t axle sprockets. we hold the throttle down wide open and just do not care if they blow up. it’s whoever wins the race. They will not suck the bowl dry and I’m almost sure they all run a tad rich. I think your trying to put way to much fuel through that 212cc

 

[tylershg]

you have a 212cc I have 304cc’s.. You say the you pulled the spark plug and it looks like it is running rich. your running a 120 jet? I‘ll go check the hour meter but I know the last time it read above 10 hours of seat time. I have the stock 90 jet in all the 304’s with upgraded springs carb/header torque converters etc.. i’m only after speed. I run a 14t t/q sprocket and 60t axle sprockets. we hold the throttle down wide open and just do not care if they blow up. it’s whoever wins the race. They will not suck the bowl dry and I’m almost sure they all run a tad rich. I think your trying to put way to much fuel through that 212cc View attachment 302095

I mean that's what everyone is saying to do and that's my conclusion so far is to much fuel. I'm basically at sea level so I'm not sure it affects it. but I will try a smaller jet when I am home

 

[Thepaetsguy]

I mean that's what everyone is saying to do and that's my conclusion so far is to much fuel. I'm basically at sea level so I'm not sure it affects it. but I will try a smaller jet when I am home

The stock 90 jet would be a start and go up small from there.. not sure how it‘s gonna handle more then the stock 90

 

[tylershg]

The stock 90 jet would be a start and go up small from there.. not sure how it‘s gonna handle more then the stock 90

I will test it out. I just dont understand how all these yourube channels that have been messing with these engines for years and have perfected the craft of building and tuning then, have fed me somewhat false info. maybe they are at a different altitude?

 

[Minimichael]

A chikuni is not a mikuni tho. And while all of these concerns being aired could be a culprit, it's best to start at a beginning. That's why I say read the manual above, and the linked article from Affordable Go Karts. Furthermore I don't think your air screw issue is much affected by the main jet at this point, whether 90 or 120. The slow/pilot jet controls at lower rpms, anyway. And I have heard they're sensitive to float level. I believe checking float height is in that manual. Stay on task and work through it. Sparkwizard could be spot on, so keep an eye on the float issue, but keep tuning, as I believe the pilot jet will be the next step.

Tuning a slide carb is a multi-step process. If you take your time to understand it, you'll be able to tweak the most out of it. Oh and never use carb cleaner on the rubber gaskets, as it will cause them to expand and then not fit anymore.

 

[tylershg]

A chikuni is not a mikuni tho. And while all of these concerns being aired could be a culprit, it's best to start at a beginning. That's why I say read the manual above, and the linked article from Affordable Go Karts. Furthermore I don't think your air screw issue is much affected by the main jet at this point, whether 90 or 120. The slow/pilot jet controls at lower rpms, anyway. And I have heard they're sensitive to float level. I believe checking float height is in that manual. Stay on task and work through it. Sparkwizard could be spot on, so keep an eye on the float issue, but keep tuning, as I believe the pilot jet will be the next step.

Tuning a slide carb is a multi-step process. If you take your time to understand it, you'll be able to tweak the most out of it. Oh and never use carb cleaner on the rubber gaskets, as it will cause them to expand and then not fit anymore.

ok thanks for the great info I will try to do all of this today. I'll get it soon I just know jt

 

[sparkwizard]

Oh, by the way, if you say "YOU TUBE" again, I'm out. Just my old grumpy opinion. Tools will fix it. Phone never will.

 

[tylershg]

Oh, by the way, if you say "YOU TUBE" again, I'm out. Just my old grumpy opinion. Tools will fix it. Phone never will.

ok I won't mention it again. I was just saying it was somewhat helpful for me starting out. anyways I've attached a few pics of the carb. the main jet is a 120. I think the one that screws in above the main jet is the pilot and it has 12 holes in it. and finally I saw another jet like thing that I unscrewed and it has 6 holes.9002687&poi

 

[Minimichael]

From right to left here, you're looking at your main jet, the pilot (aka slow) jet, and then the emulsion tube (which the main lives at the bottom of). Any marking on the pilot jet?

 

[tylershg]

From right to left here, you're looking at your main jet, the pilot (aka slow) jet, and then the emulsion tube (which the main lives at the bottom of). Any marking on the pilot jet?

I don't think so let me go check