Sheng wey carb problems

banditorama · 09-29-2015, 03:43 PM

I just finished a Lifan 125cc engine swap into my panterra 90cc frame and I'm having issues with the carburetor I used from my old 86cc engine. I can get the bike to run relatively well, it idles fine and if you ease onto the power it goes like Hell, but the power delivery is choppy at best. I know this thing needs more fuel than the stock jets can give it, but I can't figure out what the carb model or size is. The side of the carb says sheng wey d19 but I can't find this exact carburetor anywhere. Can anyone tell me what this carb is? Where to find jets? And maybe give me a good base idea of what size I should be running? I'm not the best when it comes to carburetion so don't make too much fun of me lol. Name: 1443555737289-155301936.jpg
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Name: 1443555737289-155301936.jpg
Views: 7422
Size: 87.9 KB

Mudflap · 09-29-2015, 04:35 PM

Most Lifan 125s I've seen are running a 24mm carb, sounds like yours may be a 19mm. It's important to have an intake with no steps, meaning the carb outlet should match up exactly with the intake tube which should match up with the cylinder head.

humanbeing · 09-29-2015, 08:11 PM

Sheng Wey is a Taiwanese brand that sometimes NOT 100% compatible w/ mainstream Japanese brand.
You can tell the type (Keihin/Mikuni) by http://jetsrus.com/FAQs/FAQ_identify_that_jet.htm
What's ur current needle position? Move c-clip allow more fuel...
--http://www.walbro.com/media/22805/PZ-Tune.pdf
PZ22 is more suitable for 125 https://item.taobao.com/item.htm?id=41725368091

Weldangrind · 09-30-2015, 11:28 AM

NOT going to make fun of you; we all started somewhere. I learn something on this forum every day.

Remove the carb, remove the bowl and then unscrew the brass main jet that is in the middle. What number is stamped on it? Is it totally clean inside? You can carefully clean it with some spray carb cleaner and a wire bristle from a wire brush.

Weldangrind · 09-30-2015, 11:28 AM

BTW, please take a pic of the jet and show us.

Does it idle ok? If so, don't worry about removing the slow jet that is adjacent to the main jet.

banditorama · 09-30-2015, 04:15 PM

Hey thanks for all the help guys! The bike idles good, once I get home from work I'll take the jet out and show you guys a picture. I know the jets are clean cause I just pulled the carb apart and cleaned everything in July and it's been run 3 or 4 times a week since.

Weldangrind · 10-01-2015, 11:03 AM

I'm glad to hear that it idles fine; it's the slow jet that can be a pain to find a replacement for. You should have no trouble finding a main jet.

banditorama · 10-21-2015, 06:54 PM

It's been a busy couple of weeks, sorry I haven't replied in a while. I ended up dropping the needle clip down a notch and playing with the fuel screw, got the bike running real good! But my buddy who got me the engine ended up giving me a new 21mm carb for it, I got that torn apart and am in the process of cleaning it. Ordered a new intake and spacer gasket because the old one from my 90cc was way too small. Once that comes in and the new paint job is done setting I'll get it back together and see how she runs

Weldangrind · 10-22-2015, 10:59 AM

Thanks for the update. Please continue to share your progress.

Tranberg · 03-18-2016, 06:10 AM

My Zongshen ZS125-47 underbone also has a Sheng Wey carburetor, albeit 22mm.

The unmarked main jet is to small, so first step was to identify the size by a jet gauge.

0.75 mm passes, 0.80mm doesn't.

Actually buying a new jet is damn near impossible.

The jet is used in small Keihin carburetors used in small Honda motorcycles and gardening equipment, and you can't buy a jet kit with 5 or 10 jets at a good price, they have to be individually ordered to the tune of $12 each.

For this low budget toy, 60 bucks for a few jets to fine tune seems pretty steep.

I can't find jets on aliexpress or taobao

pete · 03-18-2016, 09:49 PM

Quote:

Originally Posted by Tranberg

Actually buying a new jet is damn near impossible.

The jet is used in small Keihin carburetors used in small Honda motorcycles and gardening equipment, and you can't buy a jet kit with 5 or 10 jets at a good price, they have to be individually ordered to the tune of $12 each.

You were saying !!!!!! Heres a 2 minute search...
it just goes on & on....
Main jets avaraging around 1$ each & free shiping...

google is your freind.......

http://www.aliexpress.com/item/Mikun...d-6684e4cf9580

http://www.aliexpress.com/item/7-pcs...d-6684e4cf9580

http://www.aliexpress.com/item/New-m...d-6684e4cf9580

http://www.aliexpress.com/item/New-m...d-6684e4cf9580

humanbeing · 03-19-2016, 12:28 AM

Quote:

Originally Posted by Tranberg

...I can't find jets on aliexpress or taobao

Shops http://shop35091180.taobao.com | http://shop36761007.taobao.com | http://shop148273066.taobao.com located at a place aka ""capital of carburettor". If can't find from above = almost NO compatibles at reasonable price...

Adjuster · 03-18-2016, 08:42 AM

I have a 125cc engine with a 22mm Sheng Way as well I believe. I also own a set of jet micro drill bits. What should I drill my bits out to?

/

Tranberg · 03-18-2016, 11:10 AM

You could follow this guide: https://www.affordablegokarts.com/Dr...ain%20Jets.php

I pulled the trigger on a Mikuni carburetor instead. £20 shipped ($29) and jets are available locally.

Tranberg · 03-19-2016, 12:51 PM

I thank you, Pete and Humanbeing, for helping me prove that the main jet for the Sheng Wey carburetor is damn near impossible to purchase, except as original Honda spares a $12/each (JetsRus charge $25 shipping costs and i risk customs fees on top of that)

The main jet looks like this:

OVERALL LENGTH = 8.5 mm
SHAFT DIAMETER = 5.5 mm
DIAMETER OF THREAD = 6.9 mm
KEIHIN 99101-124 and 99101-ZF5

09-29-2015, 03:43 PM	#1
banditorama Join Date: Jul 2015 Posts: 8	Sheng wey carb problems I just finished a Lifan 125cc engine swap into my panterra 90cc frame and I'm having issues with the carburetor I used from my old 86cc engine. I can get the bike to run relatively well, it idles fine and if you ease onto the power it goes like Hell, but the power delivery is choppy at best. I know this thing needs more fuel than the stock jets can give it, but I can't figure out what the carb model or size is. The side of the carb says sheng wey d19 but I can't find this exact carburetor anywhere. Can anyone tell me what this carb is? Where to find jets? And maybe give me a good base idea of what size I should be running? I'm not the best when it comes to carburetion so don't make too much fun of me lol.
	0

09-29-2015, 08:11 PM	#3
humanbeing Join Date: Mar 2008 Posts: 2,436	Sheng Wey is a Taiwanese brand that sometimes NOT 100% compatible w/ mainstream Japanese brand. You can tell the type (Keihin/Mikuni) by http://jetsrus.com/FAQs/FAQ_identify_that_jet.htm What's ur current needle position? Move c-clip allow more fuel... --http://www.walbro.com/media/22805/PZ-Tune.pdf PZ22 is more suitable for 125 https://item.taobao.com/item.htm?id=41725368091 __________________ Last edited by humanbeing; 09-30-2015 at 12:53 AM.
	0

09-30-2015, 11:28 AM	#4
Weldangrind Join Date: Mar 2009 Location: Sardis, BC, Canada Posts: 25,977	NOT going to make fun of you; we all started somewhere. I learn something on this forum every day. Remove the carb, remove the bowl and then unscrew the brass main jet that is in the middle. What number is stamped on it? Is it totally clean inside? You can carefully clean it with some spray carb cleaner and a wire bristle from a wire brush. __________________ Weldangrind "I figure I'm well-prepared for coping with a bike that comes from the factory with unresolved issues and that rewards the self-reliant owner." - Buccaneer
	0

09-30-2015, 11:28 AM	#5
Weldangrind Join Date: Mar 2009 Location: Sardis, BC, Canada Posts: 25,977	BTW, please take a pic of the jet and show us. Does it idle ok? If so, don't worry about removing the slow jet that is adjacent to the main jet. __________________ Weldangrind "I figure I'm well-prepared for coping with a bike that comes from the factory with unresolved issues and that rewards the self-reliant owner." - Buccaneer
	0

10-01-2015, 11:03 AM	#7
Weldangrind Join Date: Mar 2009 Location: Sardis, BC, Canada Posts: 25,977	I'm glad to hear that it idles fine; it's the slow jet that can be a pain to find a replacement for. You should have no trouble finding a main jet. __________________ Weldangrind "I figure I'm well-prepared for coping with a bike that comes from the factory with unresolved issues and that rewards the self-reliant owner." - Buccaneer
	1

09-29-2015, 04:35 PM	#2
Mudflap Join Date: Sep 2014 Posts: 1,929	Most Lifan 125s I've seen are running a 24mm carb, sounds like yours may be a 19mm. It's important to have an intake with no steps, meaning the carb outlet should match up exactly with the intake tube which should match up with the cylinder head.
	0

09-30-2015, 04:15 PM	#6
banditorama Join Date: Jul 2015 Posts: 8	Hey thanks for all the help guys! The bike idles good, once I get home from work I'll take the jet out and show you guys a picture. I know the jets are clean cause I just pulled the carb apart and cleaned everything in July and it's been run 3 or 4 times a week since.
	0

10-21-2015, 06:54 PM	#8
banditorama Join Date: Jul 2015 Posts: 8	It's been a busy couple of weeks, sorry I haven't replied in a while. I ended up dropping the needle clip down a notch and playing with the fuel screw, got the bike running real good! But my buddy who got me the engine ended up giving me a new 21mm carb for it, I got that torn apart and am in the process of cleaning it. Ordered a new intake and spacer gasket because the old one from my 90cc was way too small. Once that comes in and the new paint job is done setting I'll get it back together and see how she runs
	1

10-22-2015, 10:59 AM	#9
Weldangrind Join Date: Mar 2009 Location: Sardis, BC, Canada Posts: 25,977	Thanks for the update. Please continue to share your progress. __________________ Weldangrind "I figure I'm well-prepared for coping with a bike that comes from the factory with unresolved issues and that rewards the self-reliant owner." - Buccaneer
	0

03-18-2016, 06:10 AM	#10
Tranberg Join Date: Feb 2016 Location: Denmark, Europe Posts: 53	My Zongshen ZS125-47 underbone also has a Sheng Wey carburetor, albeit 22mm. The unmarked main jet is to small, so first step was to identify the size by a jet gauge. 0.75 mm passes, 0.80mm doesn't. Actually buying a new jet is damn near impossible. The jet is used in small Keihin carburetors used in small Honda motorcycles and gardening equipment, and you can't buy a jet kit with 5 or 10 jets at a good price, they have to be individually ordered to the tune of $12 each. For this low budget toy, 60 bucks for a few jets to fine tune seems pretty steep. I can't find jets on aliexpress or taobao
	1

03-18-2016, 08:42 AM	#13
Adjuster Join Date: Dec 2014 Location: Deerfield Beach FL Posts: 1,410	I have a 125cc engine with a 22mm Sheng Way as well I believe. I also own a set of jet micro drill bits. What should I drill my bits out to? /
	1

03-18-2016, 11:10 AM	#14
Tranberg Join Date: Feb 2016 Location: Denmark, Europe Posts: 53	You could follow this guide: https://www.affordablegokarts.com/Dr...ain%20Jets.php I pulled the trigger on a Mikuni carburetor instead. £20 shipped ($29) and jets are available locally.
	1

03-19-2016, 12:51 PM	#15
Tranberg Join Date: Feb 2016 Location: Denmark, Europe Posts: 53	I thank you, Pete and Humanbeing, for helping me prove that the main jet for the Sheng Wey carburetor is damn near impossible to purchase, except as original Honda spares a $12/each (JetsRus charge $25 shipping costs and i risk customs fees on top of that) The main jet looks like this: OVERALL LENGTH = 8.5 mm SHAFT DIAMETER = 5.5 mm DIAMETER OF THREAD = 6.9 mm KEIHIN 99101-124 and 99101-ZF5
	1