Pre-Purchase Carburetor Advice

tpelle · 07-13-2022, 10:55 AM

Thinking about a 250cc (I know, really 229cc) China Bike. I don't want EFI as I prefer the simplicity of a carburetor, but I wonder about the standard carb that comes on these bikes. I see that Venom offers the upgrade to a Mikuni or a Nibbi.

Mikuni strikes me as being a well-respected name, where Nibbi is a brand that I am not familiar with. I believe both of them use a "cold start enrichener" system as opposed to a butterfly choke, which I think I would like. I've seen the Mikuni carb on an old British bike, and it cold-started almost instantaneously!

Anyway, what is the opinion of the folks here with regards to stock, Mikuni, or Nibbi?

Falkon45 · 07-18-2022, 08:20 AM

Mikuni is a very well made, and respected Japanese carb. Usually stock on Japanese bikes, if they don't have a Keihin installed.

Nibbi is a well made, and respected Chinese/ Taiwanese carb, and is typically an upgrade for China bikes. I have a Nibbi PE26 on my Apollo Z20. I never had a problem getting my bike to start after starting it, until I took it up to Kentucky (sea level difference between Bowling Green and Savannah made for a very unhappy bike).

But, There are two very different Nibbis. The dark colored ones are their high end units with much better QC. I have one if their natural colored PE26s, and the QC isn't nearly as good. The cap for the throttle slide doesn't quite sit correctly, and a few external things aren't great. But internally, it's just as good as the painted ones.

For your engine, I'd look at the PWK series of carbs. I'm actually going to be purchasing one for my SSR SR250, as the previous owner bought a PWK38 for it, and that's too big, which is why the bike isn't running in the first place.

letsride · 07-18-2022, 09:29 AM

Depending on the Bike you get of course but the Brozz comes with a Genuine Keihin carb already on it. And some people have had good luck keeping the Carb that comes on their bike, with just jetting it properly. There are China Bike upgrade kits on ebay to rejet the stock carb. The stock carb has some weird screws in the float bowl, you have to take a dremel with a cut off wheel and cut a slot for a screw diriver to get the screws out. But the upgrade / jet kits come with new screws. These kits have, jets, valve cover gasket, and Front sprocket. Motocheez on youtube has videos on how to do all this. Good luck on your purchase

Oldenslow · 07-18-2022, 02:07 PM

I'll just point out this -- although carburetor upgrades, gearing changes, etc. are sometimes needed, and may, indeed, increase performance in some cases if done correctly -- it is not at all unusual for cheap Chinese bikes to be pretty much satisfactory as they are. My DF 250RTG is an example -- other than replacing some sub-par fasteners, the spark plug, and the primitively-made lightbulbs it has been perfectly satisfactory. (Replacing that spark plug is like adding a supercharger.) Of course, I didn't expect anything but some reliable, economical transportation that could also provide a bit of fun, and not some monster performance machine.

buzz · 08-06-2022, 07:07 AM

Hello i have a TBR7 running just fine stock carburetor with just rejettting

07-13-2022, 10:55 AM	#1
tpelle Join Date: Mar 2022 Posts: 45	Pre-Purchase Carburetor Advice Thinking about a 250cc (I know, really 229cc) China Bike. I don't want EFI as I prefer the simplicity of a carburetor, but I wonder about the standard carb that comes on these bikes. I see that Venom offers the upgrade to a Mikuni or a Nibbi. Mikuni strikes me as being a well-respected name, where Nibbi is a brand that I am not familiar with. I believe both of them use a "cold start enrichener" system as opposed to a butterfly choke, which I think I would like. I've seen the Mikuni carb on an old British bike, and it cold-started almost instantaneously! Anyway, what is the opinion of the folks here with regards to stock, Mikuni, or Nibbi?
	0

07-18-2022, 09:29 AM	#3
letsride Join Date: Oct 2013 Location: Leesville SC Posts: 835	Depending on the Bike you get of course but the Brozz comes with a Genuine Keihin carb already on it. And some people have had good luck keeping the Carb that comes on their bike, with just jetting it properly. There are China Bike upgrade kits on ebay to rejet the stock carb. The stock carb has some weird screws in the float bowl, you have to take a dremel with a cut off wheel and cut a slot for a screw diriver to get the screws out. But the upgrade / jet kits come with new screws. These kits have, jets, valve cover gasket, and Front sprocket. Motocheez on youtube has videos on how to do all this. Good luck on your purchase __________________ My Stable- 2022 Lifan KPX250 , 2023 Royal Enfield Himalayan, 1992 Honda GL1500 Goldwing, SSR 70 Auto, Kymco Mongoose 90, Honda Four Trax 300
	1

07-18-2022, 08:20 AM	#2
Falkon45 Join Date: Aug 2020 Location: Savannah, Ga Posts: 759	Mikuni is a very well made, and respected Japanese carb. Usually stock on Japanese bikes, if they don't have a Keihin installed. Nibbi is a well made, and respected Chinese/ Taiwanese carb, and is typically an upgrade for China bikes. I have a Nibbi PE26 on my Apollo Z20. I never had a problem getting my bike to start after starting it, until I took it up to Kentucky (sea level difference between Bowling Green and Savannah made for a very unhappy bike). But, There are two very different Nibbis. The dark colored ones are their high end units with much better QC. I have one if their natural colored PE26s, and the QC isn't nearly as good. The cap for the throttle slide doesn't quite sit correctly, and a few external things aren't great. But internally, it's just as good as the painted ones. For your engine, I'd look at the PWK series of carbs. I'm actually going to be purchasing one for my SSR SR250, as the previous owner bought a PWK38 for it, and that's too big, which is why the bike isn't running in the first place.
	0

07-18-2022, 02:07 PM	#4
Oldenslow Join Date: Mar 2020 Posts: 153	I'll just point out this -- although carburetor upgrades, gearing changes, etc. are sometimes needed, and may, indeed, increase performance in some cases if done correctly -- it is not at all unusual for cheap Chinese bikes to be pretty much satisfactory as they are. My DF 250RTG is an example -- other than replacing some sub-par fasteners, the spark plug, and the primitively-made lightbulbs it has been perfectly satisfactory. (Replacing that spark plug is like adding a supercharger.) Of course, I didn't expect anything but some reliable, economical transportation that could also provide a bit of fun, and not some monster performance machine.
	2

08-06-2022, 07:07 AM	#5
buzz Join Date: Dec 2020 Location: Dayton Pa. Posts: 870	Hello i have a TBR7 running just fine stock carburetor with just rejettting
	0