tunable carb with stock airbox? Gen 2 Vader

[GScott]

Got my new Boom Vader BD125-10. It seems to have the tank venting problem, is hard to start in the very cold, and the handlebar 'choke' or fuel enricher thing does absolutely nothing. I will be digging in to do some of the common repairs, like cleaning up the vacuum lines, tightening and replacing bolts, and go from there..

Does anyone know of a more tunable carb that works with the stock airbox? I would like to keep the stock airbox and filter since it is protected from the weather and provides rigidity to the flimsy body panels. I also like the idea of the fuel petcock on the carb, and the choke cable at the handle bars. I'm not a fan of the air filter sitting behind the front tire soaking up water and mud; I would much rather open up the restrictions in the airbox and keep that box filter if possible.

I haven't dug in yet, but I suspect the carb is a keihin PZ19 copy. Does that seem right? Are the aftermarket carbs fairly tunable? Has anyone found which size jets work to start? I know this carb seems a bit small, but I'm not really planning on changing the exhaust or going for max power...

[Musictrek]

Originally Posted by GScott

Got my new Boom Vader BD125-10. It seems to have the tank venting problem, is hard to start in the very cold, and the handlebar 'choke' or fuel enricher thing does absolutely nothing. I will be digging in to do some of the common repairs, like cleaning up the vacuum lines, tightening and replacing bolts, and go from there..

Does anyone know of a more tunable carb that works with the stock airbox? I would like to keep the stock airbox and filter since it is protected from the weather and provides rigidity to the flimsy body panels. I also like the idea of the fuel petcock on the carb, and the choke cable at the handle bars. I'm not a fan of the air filter sitting behind the front tire soaking up water and mud; I would much rather open up the restrictions in the airbox and keep that box filter if possible.

I haven't dug in yet, but I suspect the carb is a keihin PZ19 copy. Does that seem right? Are the aftermarket carbs fairly tunable? Has anyone found which size jets work to start? I know this carb seems a bit small, but I'm not really planning on changing the exhaust or going for max power...

The problem may not be the carb, but the flow control valve thats inline of the vent tank thats creating a vacuum in the tank and causing the fuel to stop flowing. I know because I had that problem with the same Vader. Check out my video on the problem and to fix. After that fix, this bike is way reliable so far and no issues with carb performance.

[GScott]

Yes. Thanks for that. I had same issue as yours. The check valve was hanging sideways and not working correctly. Once I got the plastic panels off I see lots of QC issues; Mismatched bolts. Missing screws. Wires and vacuum lines routed poorly. Chain is super tight. But I knew all that from reading about these bikes before I bought it.

The carb is marked Sheng Wey PZ20.

I was gonna start by bumping up the idle, it was too low. But today it doesn't want to start at all. I knew I was buying a stack of parts. Now I get to do the set up!

[Musictrek]

Originally Posted by GScott

Yes. Thanks for that. I had same issue as yours. The check valve was hanging sideways and not working correctly. Once I got the plastic panels off I see lots of QC issues; Mismatched bolts. Missing screws. Wires and vacuum lines routed poorly. Chain is super tight. But I knew all that from reading about these bikes before I bought it.

The carb is marked Sheng Wey PZ20.

I was gonna start by bumping up the idle, it was too low. But today it doesn't want to start at all. I knew I was buying a stack of parts. Now I get to do the set up!

Luckily I was only doing short warm up trips around my neighborhood when mine was cutting out. The other odd thing is the 2020 speedo seems to be non adjustable for the wheel diameter to adjust the mph to a gps. I put a 2019 speedo on and dialed in the speedo to gps accuracy. They (China) could improve so much by just doing a little bit of QC before sending units out the door so quickly.