My bike cut out the other day .?

Question

on inspection i found out it was spark plug . it has oil deposits on it .does anyone know why this is and how to stop it happening again?? the bike is gilera rv125 and its 2 stroke

Answer 1

The type of plug fitted by the manufacturer assumes average use with the correct oil ratio. If you do mainly short trips the plug may not be getting hot enough to burn off the oil in the fuel mix. You could try one or two things. Fit a hotter grade of plug. Change to a high quality  fully synthetic oil. Or do both.

The plug manufacturers have charts showing plug heat ranges so it should be simple to go up a notch. Fully synthetic oil will be much less likely to oil your plug and your bike will last longer too. One final thing, if your fuel is premix be very accurate with the recommended ratio. If it's injected from a separate tank you need to check that it is dosing correctly.

Answer 2

take the spark plug off and put a bit of petrol in put the spark plug back in and start your engine,it should fire up first time

Answer 3

Most probable without knowing anymore details -

Needs a top end rebuild (cylinder, piston & rings).

The low compression won't fully burn the oil in the pre-mix.

To much oil in the pre-mix.

Cheap 2 cycle oil - use quality, brand name 2 cycle oil made for motorycycles - the cruddy stuff doesn't burn properly.

Dirty air cleaner causing it to run rich.