2001 cr125 problems need serious help

[ezza]

I just got a 2001 cr125 which just had a top end re-build (the guy done it himelself because he is a mechanic)and done the jets and all. I took it for a few spins up and down my street it was running fine. then i put 40:1 petrol in it like the guy said. i put 2T castrol 2 stroke oil in and ever since then it runs like **** and doesnt start. we have tried push starting it and it goes but dies out wat can i do? i have drained the carbie the tank cleaned the spark plug which was full of oil. and put in different oil and still 40:1 ratio it started and run like a dream once again then i left it for five minutes then same problems all over again what can i do?! i need help bad. :bang:

I am starting to think theres sumthing wrong with my bike and not my petrol.

 

[slodad]

Is the Castrol a castor based oil? If it is, and the mix in the tank was a petroleum based oil, you can have real problems. Try emptying the tank and drain the carburetor and then refill the tank with a new batch of fuel. If that cures the problem, discard the old batch and keep using whatever oil is in the new batch.

You must never mix castor based lubricants with petroleum based ones. Synthetics can usually mix with either.