Terry Syd
Pinnacle OPE Member
- Local time
- 9:40 PM
- User ID
- 575
- Joined
- Jan 18, 2016
- Messages
- 1,589
- Reaction score
- 5,984
- Location
- Comboyne, NSW Australia

Brewz and I have been discussing the modded Walbro 460 carb as a viable carb. It would have a venturi of 17.5mm and completely altered jetting. With the offset discharge nozzle and the larger venturi, it looks like it could flow quite well - and it would be an easy swap.
It took me a while to figure that freaking carburetor out. It appears the factory 'hid' the EPA restriction to the low speed circuit in the tunnel for the main discharge nozzle. After all the mental gymnastics I went through to figure out WHY they did it that way, it appears they wanted to make the carb EPA tamper proof. - I think I figured out how to tamper with it. Not a hard set of mods, but it requires that you get into the guts of the carb.
I've got a way to go, but I'm on the home-stretch now. The carb is working very well with great stability in the fuel mixture. I think as soon as I get the metering spring right (for my 64cc 029) the carb will be a top carb to mod as a replacement for the HD series. After I get it dialed in on the 029/390, I might try to see if it will top the modded Zama on my 77cc 'Husky'.
It took me a while to figure that freaking carburetor out. It appears the factory 'hid' the EPA restriction to the low speed circuit in the tunnel for the main discharge nozzle. After all the mental gymnastics I went through to figure out WHY they did it that way, it appears they wanted to make the carb EPA tamper proof. - I think I figured out how to tamper with it. Not a hard set of mods, but it requires that you get into the guts of the carb.
I've got a way to go, but I'm on the home-stretch now. The carb is working very well with great stability in the fuel mixture. I think as soon as I get the metering spring right (for my 64cc 029) the carb will be a top carb to mod as a replacement for the HD series. After I get it dialed in on the 029/390, I might try to see if it will top the modded Zama on my 77cc 'Husky'.