Nibbi PE 24 on upgraded predator 212 hemi.

#1
Hi, I have a Predator 212 Hemi and just finished my build with

Billet flywheel
Billet Rod
22lb springs
Hot 265 Cam

I'm having quite a bit of trouble getting the carb tuned and jetted correctly, I'm at around 650 ft elevation. If anyone has a similar build or has any helpful info I would greatly appreciate it. I mainly need to find the best jetting and needle setup and then I can get the idle and Air-Fuel ratio from there. Thanks!
 

Minimichael

Well-Known Member
#2
Guessing you're running an open header? What do you mean you're having trouble? What's it doing? I have messed with the nibbi pe24 on a different motor and I've determined it uses needles equivalent to the Keihin PWK28.
 
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#3
Guessing you're running an open header? What do you mean you're having trouble? What's it doing? I have messed with the nibbi pe24 on a different motor and I've determined it uses needles equivalent to the Keihin PWK28.
Yes i have an open header but have a muffler that i’m waiting to put on. It runs decently but not great, it sprays a decent amount of gas out of the carb and out of the bottom of the bowl sometimes, i’ve determined it’s not the gasket it’s coming out of the screw thing on the bottom of the bowl.
 

Minimichael

Well-Known Member
#4
Leaking fuel is not the same as a needle or jet problem. What jets are in place and where's your needle at? Have you checked your plug color after running around at WOT?
 

Minimichael

Well-Known Member
#5
If you're having trouble getting up to WOT due to sputtering/gasping in the early throttle range, try raising the needle a notch or two by dropping the clip. Your mission is to run a couple laps near WOT and then kill it and check your plug color. Light brown is best (look it up if you have to), as this will indicate your main jet is feeding all the motor wants but not much more (too black) or less (too white). Start with the main jet that came stock and then work your way up (probably) but don't expect to go more than 2 or 3 digits higher. Once you got your plug color right, the main jet is done. The pilot should change only as necessary, and I wouldn't expect to go more than one number higher than stock. My experience with nibbi showed me that finding the sweet spot on the mixture screw was not easy. It was very narrow. Forget 1/4 turns. More like 1/16 or less.

Last I checked, nibbi only sold one needle. And in my experience, it is a lean one in early throttle range – hence raising it up right from the get-go. Like I said above, the keihin pwk28 needle gave me the variety I was needing for my project. If I had to do it again I might try to linnish the stock needle my self (and maybe that's what Nibbi "racing" folks would expect).

Somebody running a 212 may have a better idea on your main jet size to help you get started tho. Also, taping a range chart to my throttle helped me identify where the performance issues needed to be addressed. Hope this helps.
 

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#7
If you're having trouble getting up to WOT due to sputtering/gasping in the early throttle range, try raising the needle a notch or two by dropping the clip. Your mission is to run a couple laps near WOT and then kill it and check your plug color. Light brown is best (look it up if you have to), as this will indicate your main jet is feeding all the motor wants but not much more (too black) or less (too white). Start with the main jet that came stock and then work your way up (probably) but don't expect to go more than 2 or 3 digits higher. Once you got your plug color right, the main jet is done. The pilot should change only as necessary, and I wouldn't expect to go more than one number higher than stock. My experience with nibbi showed me that finding the sweet spot on the mixture screw was not easy. It was very narrow. Forget 1/4 turns. More like 1/16 or less.

Last I checked, nibbi only sold one needle. And in my experience, it is a lean one in early throttle range – hence raising it up right from the get-go. Like I said above, the keihin pwk28 needle gave me the variety I was needing for my project. If I had to do it again I might try to linnish the stock needle my self (and maybe that's what Nibbi "racing" folks would expect).

Somebody running a 212 may have a better idea on your main jet size to help you get started tho. Also, taping a range chart to my throttle helped me identify where the performance issues needed to be addressed. Hope this helps.
thanks a lot I will let you know how it goes getting it tuned
 
#12
The reason Mikuni carbs are suggested is because they are easier to tune and they seem to stay in tune a whole lot longer.
As stated above, the idle mixture screw on Nibbi carbs is very sensitive. It can vibrate from good to terrible in a 1/4 turn.

We wish you the best of luck.
Have fun and be safe.
 

SAS289

Well-Known Member
#13
#14
Is this the carb you are using? Amazon.com: NIBBI Racing Carburetor PE24FL Flange Fit For Cross Bike 70CC 100CC 125CC Scooter HONDA YAMAHA SUZUKI : Automotive

Look at the reviews. There may be helpful information.

Another comment about this.... I'm not serious about slide carbs. That's why I got the Mikuni clone. If I were more serious about them I certainly wouldn't get a Mikuni VM22 at a higher cost and less performance than this carb.
yes that’s the carb i have except it’s the one without a flange, i’ll look at the reviews, thank you.
 
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