Frankinstein YT175 trike, carb overflowing

[bobotech]

I have a titled and registered 85 YT125 trike that I have converted over to a YT175.

It has a 83 YT175 top end, piston/rings from a IT175, YT175 front end, an aftermarket mystery pipe, an 70's Yamaha silencer/spark arrestor, and a mystery carb.

I have tried two refurbed carbs that I have. They are both larger Mikunis with lever chokes on the carb (no cables). I believe one is a 34mm and the other is a 32mm but I am not sure.

I have a fuel pump from a YT175 also inline with the YT125 tank and carb.

The problem is that when the trike runs, the fuel bowl eventually overflows and starts pissing out fuel out the vent on the bottom and flooding out the engine. It is acting like the fuel pump is pushing too much fuel but that doesn't make sense.

if I take the carbs off the trike and clean it out and fill the bowl with water then put a rubber hose on the fuel inlet and try blowing with all my might, it won't blow though which is suppsoed to happen (the float is shutting off the needle). If I pour the water out, I can blow though no problem. This works on both of the carbs.

What in the heck am I missing?> Is there supposed to be a fuel line return or something? I tried without the fuel pump and it jsut appears to want to starve.

[CanadianThomas]

I just went through a similar problem. My floats were not set right they were too high. In the service manual it tells me to make sure the bike is level, hook up a piece of hose to the bottom overflow, fill with gas/fluid, the level of fluid in the tube you connected (for mine) is about but not quite to the top level of the bowl. Might be worth a try.

[RubberSalt]

Check and makre sure there is nothing between the needle and seat and the floats are set right. The fuel pump is often the issue for this stuff, they are not designed to widthstand the pumps pressure. The laws of gravity should apply here still.


PS
How does the trike run with those carbs on it? I'm thinking about upgrading mine to a 34mm mikuni, I've got a spare. I'm also thinking about trying an exhaust pipe off a late model RM125 dirtbike.


Update: My carb overflowed due to a fuel pump, its a 34mm