Minibike Float bowl tuning.(With fuel pump)

[Gabrielmq23]

Got a question on float bowl tuning with a post pump. First some background info, When i first put this kehin 24mm carb it ran fine i realized that the carb wasnt getting all of the fuel from the pump since the line was too high. So I stuck the fuel line from the pump to the carb lower and that seemed to give the bike alot more fuel and obviously a lot more power(powerwheelies). But ever since i moved the fuel line lower everytime i start the bike, the fuel overflow would just shoot water out. I cant seem to get the float height to be perfect. Either the bike doesnt get enough fuel and either wont start or will bog hard when opening the throttle hard, Or the bike will run fine but dump fuel out of the overflow.

But also a second small question, if i can get the bike to not leak but bog with wot would i have to adjust the throttle needle?

 

[ole4]

"overflow would just shoot water out " IS this a Typo? I'm having a hard time understanding you question. Let me ask a couple, why are you using a fuel pump? Is it because your carb is higher than the tank or maybe you are using the stock fuel tank? Carbs generally come with a needle and seat designed for gravity feed. Depending on the pressure the fuel pump makes and the diameter of the needle seat opening sometimes the pump will push the seat open and cause the fuel level to be to high and fuel will come out of the overflow, but if water is coming out you have some real problems.

 

[Minimichael]

Yeah, you don't want water. And each one of those 3 positions and problems you describe are wrong in their own right. Here's a mikuni manual, but ya gotta stabilize the fuel flow first.

 

[Gabrielmq23]

"overflow would just shoot water out " IS this a Typo? I'm having a hard time understanding you question. Let me ask a couple, why are you using a fuel pump? Is it because your carb is higher than the tank or maybe you are using the stock fuel tank? Carbs generally come with a needle and seat designed for gravity feed. Depending on the pressure the fuel pump makes and the diameter of the needle seat opening sometimes the pump will push the seat open and cause the fuel level to be to high and fuel will come out of the overflow, but if water is coming out you have some real problems.

woops the water part was a typo sorry about that. But if the fuel pump isnt neccisary ill take it off. The reason I had it was just from insperation from those high comp high hp drag builds. I really just wanted consitency from the gas tank and didnt feel like gravity feeding was that consistant. Im using a custom tank thats pretty high up.

 

[ole4]

Those same carbs have been used on motorcycles for 80 plus years using gravity feed. fuel pump is for applications that have fuel level equal to or below carb. Try it without the pump to see if it fixes your overflow issues. Then we can try to help you with any other issues.