139QMB Carb on Huasheng?

[mark20]

You could make it work but keep in mind, this carburetor is a CV-type carb, which means the throttle range is controlled by a vacuum diaphragm. So throttle input would be lacking and might not even allow you to open up full throttle until your topped out (due to the low engagement clutch on Hash motors)

there's a reason most scooter people throw these carbs away when they want to get more performance. There really just made it to have a smoother take-off and for emissions.

Id stick to a PZ15 as mentioned above, less work, more performance and overall just a better carb than the 139QMB ones.

 

[JuraTyKokotko]

You could make it work but keep in mind, this carburetor is a CV-type carb, which means the throttle range is controlled by a vacuum diaphragm. So throttle input would be lacking and might not even allow you to open up full throttle until your topped out (due to the low engagement clutch on Hash motors)

there's a reason most scooter people throw these carbs away when they want to get more performance. There really just made it to have a smoother take-off and for emissions.

Id stick to a PZ15 as mentioned above, less work, more performance and overall just a better carb than the 139QMB ones.

Is the PZ15 bolt on?

 

[mark20]

Is the PZ15 bolt on?

Probably not as the bolt spacing is different than the haustang motors. i know a GX200 carb will fit on it, it gives you 18mm rather than the stock 12, but you have to modify the throttle system as well as the intake system for it to clear. Its the reverse of the hastang carb.

 

[Elding]

All you need is to make an adapter for that carb. I made it from exhaust pipe and then used rubber hose to connect carb to the engine, the shorter the better. Also you would need some battery pack for choke but you could also bypass it by glue that hole with epoxy. The carb runs pretty well with that engine, fuel consumption is similar to stock carb, thus when full trottle it can also "drink" up to 4L/100km which is crazy. But I reckon that this carb would give you few km/h more than the stock one

 

[JuraTyKokotko]

All you need is to make an adapter for that carb. I made it from exhausted pipe and then used rubber hose to connect carb to the engine, the shorter the better. Also you would need some battery pack for choke but you could also bypass it by glue that hole with epoxy. The carb runs pretty well with that engine, fuel consumption is similar to stock carb, thus when full trottle it can also "drink" up to 4L/100km which is crazy. The only issue Im having with that carb is that for some reason its difficult to set stable idling speed, the engine is running about 3500 rpm, then suddenly ramp up 4500 rpm, dunno why, it happens every 30 seconds or so.View attachment 191504

Stock jet in carb? Any performance increase?

 

[Chainlube]

All you need is to make an adapter for that carb. I made it from exhausted pipe and then used rubber hose to connect carb to the engine, the shorter the better. Also you would need some battery pack for choke but you could also bypass it by glue that hole with epoxy. The carb runs pretty well with that engine, fuel consumption is similar to stock carb, thus when full trottle it can also "drink" up to 4L/100km which is crazy. The only issue Im having with that carb is that for some reason its difficult to set stable idling speed, the engine is running about 3500 rpm, then suddenly ramp up 4500 rpm, dunno why, it happens every 30 seconds or so.View attachment 191504

If you cannot maintain a steady idle, then you have an intake leak. Upon examining your photo, I would suspect intake to cylinder head connection. Looks like there is a little twist to it. Best way to confirm is to pull off intake and lay on flat surface. If you tape a sheet of sandpaper to a piece of glass and sand the intake lighty this will show if it's perfectly flat.

 

[Elding]

Main jet 80. To do with performance, I don't actually know, because I don't remember performance of the stock carb It's been a while since I had it. The difference with this GY6 carb is throttle range, you twist throttle to 1/3 and your speed is 35 km/h (in my case, it depends) but on stock carb you had to twist it to like 3/4 to get the same speed. on GY6 is not big difference at performance when throttle is 1/3 or full.

About that intake leak...I remember I was pretty careful with some leakage, thats why I used fat gasket between head and manifold and that black..thing XD But maybe you are right, either way someday, I will rebuild completely the intake manifold because its too long and hopefully I will get rid of that irregular running.

 

[Chainlube]

Main jet 80. To do with performance, I don't actually know, because I don't remember performance of the stock carb It's been a while since I had it. The difference with this GY6 carb is throttle range, you twist throttle to 1/3 and your speed is 35 km/h (in my case, it depends) but on stock carb you had to twist it to like 3/4 to get the same speed. on GY6 is not big difference at performance when throttle is 1/3 or full.

About that intake leak...I remember I was pretty careful with some leakage, thats why I used fat gasket between head and manifold and that black..thing XD But maybe you are right, either way someday, I will rebuild completely the intake manifold because its too long and hopefully I will get rid of that irregular running.

I've made a few manifold in the past. They hardly ever turn out as good as I like them too. They always run good in the end after a some aggressive filing and JB treatment.