Nibbi PEZ28 on 2024 CSC TT250 - Page 2

bigdano711 · 08-16-2024, 10:24 PM

Doesn't get much better than that. Did the stumble go away? What manual are you referring to? The one that came from CSC with the bike or a Nibbi manual? Here's what I got for Nibbi:

Sdmfjon · 08-19-2024, 10:51 PM

Update.

It's too rich. But like a hair too rich in the midrange. Random stumble coming off idle. Sounds fat like a tractor.

Going to try two things.

First. Raise the needle clip from position 3 to 2.

If that is unfavorable I'm going to try the factory combo from the PE28FL. This would lower the main jet to 112 and change the needle clip to position 4.

My manual looks different than that one. I have the factory settings for the "PE**FL" lineup and the clamp on lineup.

Sdmfjon · Today, 01:11 PM

Update. That worked. No stumbling, no gassy smell.

I still can't crack throttle from idle to anything 1/2 or beyond. If I bring the bike off idle it's fair game. Oh well. I don't want to spend 300 dollars on a really nice genuine pumper carb like my hondas have.

Final tune for now.

Stock bike. Emissions removed and a Nibbi PEZ28 fitted.

38 idle jet
Needle position 2
Air screw 1 1/2
Main jet 115.

dirtbkr188 · Today, 01:46 PM

Strictly a suggestion, you only need a screwdriver and some time - try turning the air screw IN a 1/4-turn (to richen the pilot circuit), ride the bike and see if the off-idle hesitation lessens. If so, try another 1/4-turn and test ride, until you think the hesitation is gone. If you get to being only a 1/2-turn from seated, then you might want to bump the pilot up to a #40.

Just my 2¢...

Sdmfjon · Today, 02:48 PM

I started with the 40. It made me have to put the air screw almost 3 turns out to achieve highest idle.

The 38 puts me dead between 1 1/4 and 1 1/2.

08-16-2024, 10:24 PM	#16
bigdano711 Join Date: Jun 2023 Location: Big Piney, WY Posts: 532	Doesn't get much better than that. Did the stumble go away? What manual are you referring to? The one that came from CSC with the bike or a Nibbi manual? Here's what I got for Nibbi: Attached Thumbnails __________________ 2023 Hawk 250 from XPRO off of Amazon MOUNTAIN MAN RC + MOTO on YouTube "If there were more bloody noses, there would be less wars." - Hagbard Celine "Someday, after mastering the waves, the winds, the tides and gravity, we shall harness for God the energies of love and then, for the second time in the history of the world, man will have discovered fire." - Pierre Teilhard de Chardin
	0

08-19-2024, 10:51 PM	#17
Sdmfjon Join Date: Oct 2023 Posts: 24	Update. It's too rich. But like a hair too rich in the midrange. Random stumble coming off idle. Sounds fat like a tractor. Going to try two things. First. Raise the needle clip from position 3 to 2. If that is unfavorable I'm going to try the factory combo from the PE28FL. This would lower the main jet to 112 and change the needle clip to position 4. My manual looks different than that one. I have the factory settings for the "PE**FL" lineup and the clamp on lineup.
	1

Today, 01:11 PM	#18
Sdmfjon Join Date: Oct 2023 Posts: 24	Update. That worked. No stumbling, no gassy smell. I still can't crack throttle from idle to anything 1/2 or beyond. If I bring the bike off idle it's fair game. Oh well. I don't want to spend 300 dollars on a really nice genuine pumper carb like my hondas have. Final tune for now. Stock bike. Emissions removed and a Nibbi PEZ28 fitted. 38 idle jet Needle position 2 Air screw 1 1/2 Main jet 115.
	2

Today, 01:46 PM	#19
dirtbkr188 Join Date: Aug 2009 Posts: 551	Strictly a suggestion, you only need a screwdriver and some time - try turning the air screw IN a 1/4-turn (to richen the pilot circuit), ride the bike and see if the off-idle hesitation lessens. If so, try another 1/4-turn and test ride, until you think the hesitation is gone. If you get to being only a 1/2-turn from seated, then you might want to bump the pilot up to a #40. Just my 2¢...
	0

Today, 02:48 PM	#20
Sdmfjon Join Date: Oct 2023 Posts: 24	I started with the 40. It made me have to put the air screw almost 3 turns out to achieve highest idle. The 38 puts me dead between 1 1/4 and 1 1/2.
	0