Nibbi PEZ28 on 2024 CSC TT250 - Page 3

Bill Hilly · Yesterday, 06:05 PM

This is a follow up to my post earlier today. The Nibbi PEZ is not a PZ30 clone, but it is made as a slightly more direct replacement for the PZ30. Basically the PE28FL, and the PEZ look the same, but the PEZ has about 45-46 mm O.D. breather side, and the PE28FL has about a 49mm. I think, (but don't know for sure) the PEZ has a different needle. I don't have a PE28FL around anymore to compare with, BUT I have noticed the needle on my PEZ is very sharp, and thin , and has no taper for about the first 3/4" or so. Any jet bigger than a 115 slides way down the needle. A 120 slides right down it . I realize that's probably why I had to lower the needle so far when I had my hotter motor , and was running a larger main. I don't think the needle in the PEZ is going to be ideal with larger jetting. These are pictures of the needle, and the needle with a 120 main on it. A 115 will not slide over it.http://

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ughmas · Today, 09:05 AM

I have a PE28FL and I have faced similar initial tune/jet challenges with it. I'm betting its almost the exactly the same except the OD of the inlet side. I can take some measurements if you are curious. I just took the bike out since its starting to cool down to a reasonable riding temp, I was about to take a fresh crack at tuning it. following along with your experience and will let you know what I end up with

superjocko · Today, 06:27 PM

For what it's worth, I tried a 40 and a 38 before settling on a 35 pilot. I had to have the pilot air screw out farther than I'd care to with the bigger pilot jets, and could also not achieve as clean a transition to the needle when the bigger pilots were in the carb. With the 35 pilot jet, and the needle clip in the second groove from the top (next to leanest needle position), I run my pilot air screw anywhere from 3/4 to 1-1/4 turns, depending on the elevation that I'm riding at. I just tune the pilot air screw for best idle and throttle response in a manner very similar to that in the already posted youtube video.
I'm using the same natural aluminum colored body Nibbi 28mm flange-type carb that I believe the OP is. However, my engine has the Motocult stage 3 kit installed, so your results may vary.

ughmas · Today, 07:17 PM

Quote:

Originally Posted by superjocko

For what it's worth, I tried a 40 and a 38 before settling on a 35 pilot. I had to have the pilot air screw out farther than I'd care to with the bigger pilot jets, and could also not achieve as clean a transition to the needle when the bigger pilots were in the carb. With the 35 pilot jet, and the needle clip in the second groove from the top (next to leanest needle position), I run my pilot air screw anywhere from 3/4 to 1-1/4 turns, depending on the elevation that I'm riding at. I just tune the pilot air screw for best idle and throttle response in a manner very similar to that in the already posted youtube video.
I'm using the same natural aluminum colored body Nibbi 28mm flange-type carb that I believe the OP is. However, my engine has the Motocult stage 3 kit installed, so your results may vary.

Thanks for this, that was my planned next move when I pull the bowl and needle out - I had not tried leaning out the needle (had been trying to get it to be happy on stock 3 position and 4 position richer) Will report with how it goes. what are you running for main?

Yesterday, 06:05 PM	#31
Bill Hilly Join Date: Feb 2021 Posts: 991	This is a follow up to my post earlier today. The Nibbi PEZ is not a PZ30 clone, but it is made as a slightly more direct replacement for the PZ30. Basically the PE28FL, and the PEZ look the same, but the PEZ has about 45-46 mm O.D. breather side, and the PE28FL has about a 49mm. I think, (but don't know for sure) the PEZ has a different needle. I don't have a PE28FL around anymore to compare with, BUT I have noticed the needle on my PEZ is very sharp, and thin , and has no taper for about the first 3/4" or so. Any jet bigger than a 115 slides way down the needle. A 120 slides right down it . I realize that's probably why I had to lower the needle so far when I had my hotter motor , and was running a larger main. I don't think the needle in the PEZ is going to be ideal with larger jetting. These are pictures of the needle, and the needle with a 120 main on it. A 115 will not slide over it.http://http://
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Today, 09:05 AM	#32
ughmas Join Date: Feb 2016 Location: NY Posts: 174	I have a PE28FL and I have faced similar initial tune/jet challenges with it. I'm betting its almost the exactly the same except the OD of the inlet side. I can take some measurements if you are curious. I just took the bike out since its starting to cool down to a reasonable riding temp, I was about to take a fresh crack at tuning it. following along with your experience and will let you know what I end up with __________________ 2005 CBR600RR 2016 CSC TT250 Coming Soon
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Today, 06:27 PM	#33
superjocko Join Date: Aug 2022 Location: Lincoln CA Posts: 126	For what it's worth, I tried a 40 and a 38 before settling on a 35 pilot. I had to have the pilot air screw out farther than I'd care to with the bigger pilot jets, and could also not achieve as clean a transition to the needle when the bigger pilots were in the carb. With the 35 pilot jet, and the needle clip in the second groove from the top (next to leanest needle position), I run my pilot air screw anywhere from 3/4 to 1-1/4 turns, depending on the elevation that I'm riding at. I just tune the pilot air screw for best idle and throttle response in a manner very similar to that in the already posted youtube video. I'm using the same natural aluminum colored body Nibbi 28mm flange-type carb that I believe the OP is. However, my engine has the Motocult stage 3 kit installed, so your results may vary. __________________ -2024 CSC TT250, stage 3 motocult kit, Nibbi PE28FL with custom-made cable controlled choke, modified stock muffler (larger diameter tailpipe), custom oil cooler installation with relocated stock evaporative emissions canister, oversized stainless steel footpegs, IMS folding tip shifter, a few little blingy bolts and bits. More personal preference mods to come.
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