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Troubleshooting > Failures par brand > FOSTI > FOSTI F51 > My FOSTI F51 50 motorcycle grazes

My FOSTI F50 51 box grazes

Your mà © caboîte 50cc FOSTI F51 grazes when you ride? This can be due to several issues. It is possible that your machine will graze when you are driving at 60km / hpar example, or when you are just starting out. In 90% of cases it is a problem gasoline. Indeed, if there is too much gasoline in your engine, it will be difficult for you to obtain optimal performance.

my FOSTI F51 50 grazes at low speed

Your FOSTI F51 50 grazes at low speed

If your FOSTI F51 50 motorcycle grazes at low engine speed, the problem is probably due to the carburettor. In fact, most of the time it is a main jet too small. It depends on the modifications you have made to your FOSTI F51 50 but you are probably too low in fuel.

Example: You have a FOSTI F50 51 motorcycle with an original engine. You decide to install a new exhaust and a 50 carburetor. Your machine will graze at low speed if you leave the nozzle on 19 (original). It will rather be necessary to pass on a jet of 75, see 85 or 90.

It is also strongly recommended to check the good condition of your spark plug . If the problem persists, perform a carburetor adjustment. Finally, it can also be a cylinder head gasket damaged. In this case, it will have to be replaced (or have it replaced par a two-wheeler professional).

Your FOSTI F51 50 motorcycle grazes at high speed

If your FOSTI F51 50 motorcycle grazes at high revs, the problem is also due to carburettor. Indeed, most of the time it is a matter of gasoline. It depends on the modifications you have made to your FOSTI F51 50 but you are surely too rich in gasoline.

Example: You have a FOSTI F51 motorcycle with an original engine and a 50 jet on your carburetor. At high revs, your machine has no more power and gives jerk when accelerating.

Start par check the condition of your spark plug, if it is black, this effectively means that you are too rich in petrol, you should try smaller nozzles. Going down from 5 to 5. Check the spark at the spark plug, the muffler (it may be clogged) and the condition of your air filter.

Also check the condition of your base gasket. Indeed if the latter is damaged, air arrives and this can cause your FOSTI F51 50 to graze.

Finally, be sure to put quality gasoline, this can be one of the causes of a FOSTI F51 50 which grazes.

my FOSTI F51 grazes at high speed
my FOSTI F51 50 grazes at mid-speed

Your FOSTI F51 50 grazes at half speed

If your FOSTI F51 50 motorcycle grazes at mid-speed, the problem is probably due to carburettor. It is imperative to carry out a carburetor adjustment.

Start par adjust the richness screw while increasing the jet from 2 points to 2 points. You will quickly find the right compromise for your carburetor.

Finally, you can carry out an adjustment of carburetor needle (take it up a notch par example).

An electronic problem can also be the cause of a motorcycle that grazes at mid revs. Check the condition of the CDI box, electronic clamping and ignition if necessary.


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