smoking

[thumpa6x]

i got a 300ex and it will burn oil like crazy when i start it up and it will stop after it gets warmed up but when on get on it real hard it will only do it sometimes... i just had my motor rebuilt in dec.....and it has a .40 overbore bout how many cc is that?:confused:

[nismo]

mine did the samething and after i changed the oil i run 20/50 right now it doesnt smoke. i also had a few oil leaks that i fixed, if u have any oil leaks it may let oil sit somewhere and when u start it up it burns off. not sure if i was a help

[thumpa6x]

bump

[H440exconfused]

Sounds like valve seals to me, they will smoke more when cold.

[thumpa6x]

why does it do it after its warmed up sometimes????

[H440exconfused]

Usually if its valve seals it will smoke when its warm when you really get on it and get motor reved up and those valves a working.

[thumpa6x]

how long will the seals last till i gotta put some new ones in. you got any idea what size my motor is with a .40 overbore?

[H440exconfused]

They usually dont just give out they just continue to smoke and cause you to burn oil, just keep checking your oil.

Dont qoute me exactly, but its close to a 308.5 cc

[thumpa6x]

alright thats good. j/w but how did you figure that out? ive been trying to for awhile now

[H440exconfused]

I have the formula written down, i just didnt have it around, i just gestimated cause i do know that a 400 ex 60 over is a 416, i just did a little math in head, its not exact but its close.

[TRX_Thumper]

nah its more like a 290...cause 300ex's are actually only 282 to start out with