Help

[sluda400ex]

So I have yet to figure it out. What I wanna know is whats causing my 400 to smoke in high rpms. To me it smells like oil. Dad seems to think it's gas. Do I have a gasket going bad or what's the deal. Any help opinions or ideas on getting this issue resolved are more than welcome.

[JOHNDOE83]

its not gas, if it were to much gas your motor would not fully rev out from being to rich. "true story"

Its more then likely time for a rebuild, piston and rings or valve guides/seals, might as well do both while your in there?

Try a compression test?

Always best to have a proper mechanic check it out if you arent sure what to do.

[sluda400ex]

its not gas, if it were to much gas your motor would not fully rev out from being to rich. "true story"

Its more then likely time for a rebuild, piston and rings or valve guides/seals, might as well do both while your in there?

Try a compression test?

Always best to have a proper mechanic check it out if you arent sure what to do.

So that leaves me to ask this. Whats the difficulty level on a rebuild. I know my ol 400 pretty good. And between my dad and I were pretty mechanically inclined. Is there any special tools that's needed our your basic garage tools ok.

[Fix29]

The motors on these things aren't too complicated. I would do a search in the 400ex sub forum and you will probably find some pretty good info. If not you will probably get more response/advice in that section.

[sluda400ex]

So I have another question. How do you know when you need a top end rebuild and what's the signs. And how do you know when you need a bottom end rebuild and what's the signs.