Can I use diesel fuel to wash out the inside of my crankcase on 250r atc ?

[sunnyday]

or would kerosene be better ?

the crankcase is still together on the bike, but the bike has been sitting many years and I though it may be a good idea to flushout before I add new oil to the crankcase...

also, does anyone think it would be helpful to add about 4-8 ozs of 80 weight gear oil to the 10w-40 crankcase oil...to help with viscosity when riding in the summer heat ?

[just ben]

you should be using a gear oil anyway. I run a synthetic 80/90 from amsoil.

[sunnyday]

you should be using a gear oil anyway. I run a synthetic 80/90 from amsoil.

Wow..I didnt know that....

so using a 10w-40 oil is not a good idea..even if I dont race it or run it hard ?

[just ben]

A motorcycle or atv formula is fine but they are thinner since they lube the top end also. with a 2 stroke the case oil only lubes gears and bearings and you will get the most protection from a gear oil that is safe for wet clutches.

[wonderboy]

you should be using a gear oil anyway. I run a synthetic 80/90 from amsoil.

I'm not trying to contradict you or say you are wrong, but the service manual DOES call for 10W40, not gear oil. I'd be inclined to run what the manual recommends...

Also, for hot weather, they say you can go up to 20W50.