HELP! I'm going nuts on this german version GY6 (REX 450) scooter

[stilkus]

Hello,
first of all I have some experience in turning wrenches and so on and I have actually worked with a motorcycle mechanic for a year. I have offered my help to a friend who owns a REX450 here in Germany.
this bike would start like a bitch and run crap rich till plugs are fouled then boom, DIE. I decided for a compression check first, I got something around 120 PSI. It wasn't that bad. I decided to adjust the valves as well to 0.05mm, both intake and exhaust. I checked the enricher and disabled it for now. A/F mixture screw didn't help as well cause the rpm has to be set high anyways for it to run. fuel pump doesn't drip as well:(. I checked the floats and they seem to close and not flood. Owner changed fuel and added something like seafoam here in our country. I gave up, so I decided for a cylinder* head swap and now I get 175 PSI compression which is impressive but still nothing on the idle.

the scooter has 3000kms on it and was stored for some time.

is there a way to let this motorcyle out of it's rich combustion misery ?

[bandito2]

Smaller jets maybe?

[rks]

I'm not that familiar with a Rex450 scooter, but i gather it is a Chinese GY6, with a 139QMB engine. The pictures I've found of it, pointed to the fuel tank being higher than the engine, under the seat. If that is correct, and it has the original vacuum operated fuel petcock, I would be suspect of it. Burning as rich as you say, sounds like it may sucking fuel through the petcock by way of the vac line, right into the intake manifold. This would mean unmetered fuel entering the manifold, plus the metered fuel through the carb.

If by disabling the enricher, you mean you unhooked the wires, you did the exact opposite of what you intended. Would also certainly check air intake for obstruction...and if these things are OK, then a complete new carb is dirt cheap online. ($20 - $25 US)