Flooded carb?



I have a smallframe 50s upgraded to 103.

The bike starts easy, runs good for about 2-4km and after that it can not work on high revs, but only with a gear engaged.

If I stop the bike and increase the rpm, it is ok.

If I engage a gear, it starts but when I try to increase the revs, it makes big BANG from the exhaust and it can not accelerate at all.

It just bangs and stalls.

The spark is very black after that and if I change it it becomes black again.

I tried to roatate with the idle screw and the mixture one but I just made things worse.

Also I noticed that the black rubber that connects the carb with the engine is torn on the outer part that is like a donut but not on the inner hose.


Any help?

Should I change my carb to a bigger one? (I have a 19 now)


Thank you in advance.



Hi dude


1. Please check if your piston is mounted in the right way !

There should be an arrow on the piston head, it have to show in the direction of the outlet side.


2. What jets are you using ?


By the way an 19 carb. is ok to use - no worrys [:D]






you talking about the breaker !!



Do you fixed it , engine runs ???




Hi thanks for the advice.

I have no idea about the jets, it came out of the box this way, so I did not change anything.

The cylinder is the right way, I checked it upon the installation.


I am very puzzled with this...

I think that I will reset the carb by tightening the screws and start testing to see if it will work better by turning 1/2 turn at a time...


I had this problem .

It cames from ignition, th little part who tight and separate at each Rotation ( i forgot the name) was in disfunction.




do you use the right spark plug ?


the problem is that there are many many possibilitys [:S]

ignition ok ??