Vm30 vs. Cz30 with an accelerator pump

[Bmfblackie]

First introduction: Hello all. Name is Greg. I'm a newly minted China bike rider. Just picked up a rps hawk 250. At 6'4" 275 I'm pretty impressed with the bike as it is stock. Only complaint is I can't seem to get the carb adjusted consistently. So after some searching on here I see a lot of folks switching to the Mikuni carb. I plan on a pod filter and exhaust mod in the very near future. So the easy jet selection is a bonus. But I also see some kits out there for the Cz30 carb with an accellerator pump that is recommended for 250 style engines. Includes the carb cables etc. I ride primarily at sea level to 1000 ft above. Thoughts opinions?

[Weldangrind]

Welcome!

I only have experience with the stock PZ30 carbs and the 30mm Mikuni. The Mikuni is my favourite because it's so easy to find replacement jets, and the castings are quite good.

[Its_not_a_honda]

Originally Posted by Bmfblackie

First introduction: Hello all. Name is Greg. I'm a newly minted China bike rider. Just picked up a rps hawk 250. At 6'4" 275 I'm pretty impressed with the bike as it is stock. Only complaint is I can't seem to get the carb adjusted consistently. So after some searching on here I see a lot of folks switching to the Mikuni carb. I plan on a pod filter and exhaust mod in the very near future. So the easy jet selection is a bonus. But I also see some kits out there for the Cz30 carb with an accellerator pump that is recommended for 250 style engines. Includes the carb cables etc. I ride primarily at sea level to 1000 ft above. Thoughts opinions?

This seems like a good idea. Did you ever try it?

[Megadan]

Accel pumps allow for leaner mid range and main jet settings. On a standard carb, rolling on the throttle usually means an spot of lean fueling while the increased vacuum has to pull more fuel through the jet. To compensate, many people setup the needle and main jet on the slightly rich side to compensate. The accel pump sprays fuel in to eliminate this condition. It makes for some very instant throttle response.

[Its_not_a_honda]

Originally Posted by Megadan

Accel pumps allow for leaner mid range and main jet settings. On a standard carb, rolling on the throttle usually means an spot of lean fueling while the increased vacuum has to pull more fuel through the jet. To compensate, many people setup the needle and main jet on the slightly rich side to compensate. The accel pump sprays fuel in to eliminate this condition. It makes for some very instant throttle response.

Thanks Megadan! That sounds like what I need on my Apollo 250.

What do you think of this setup?

https://www.aliexpress.com/item/KEIH...4c749f6e&tpp=1

[Megadan]

I think it is the same as any other setup you could find. The thing to pay the most attention to will be the throttle cable length. I would take the time to measure the stock cable to ensure you get one that will work.

Also, be aware that tuning an accelerator pump carb adds a level of complexity to the mix that you don't get with a standard carb. This includes not only the previously mentioned jetting, but also the timing of the pump spray with the throttle opening.