400ex smoke HELP!

[400ex_alldayy]

ok, so ive had this ex for a while now, it ran great last season but i decided to mod it. I put a 10.5:1 high comp piston with a stage 2 cam, high flow airbox and a stage 2 jet kit. When i first put it together it ran good but started smoking alot when it was warmed up and u pump the gas. so i figured it was the valve seals. took it apart and did them and it is still doing it. the smoke doesnt smell like pure oil either so i put the stock jets back in but it still does it. at idle it doesnt smoke but after pumping the gas and letting off it smokes alot and then stops like it cleans itself out. it runs pretty great too, has lots of pull and starts well but it just smokes like a 2 stroke lol im just about out of ideas, so anything u guys could tell me would be much appreciated, oh i also checked my cylinder and there was no major scores so i dunno lol

[CJM]

Chances are you didnt jet it right and it was to lean and cooked your rings. Specially when you say you changed back to stock jetting..cant do that once you do the engine work.

Alot of smoke means your rings are bad, little smoke here and there specially when cold on start up is valve seals.

Id start by doing a compression test, 120+ psi is standard, anything less than that and its def rings.

Other possible reasons its smoking:
-If it isnt burning any oil then it could be to rich. By stage 2 jet kit wtf do you mean? What jet size did you use and what type? The only jets that will work properly at keihin jets which can be bought at the dealer or online-anything else these carbs dont like.

-Possible and related to the rings-did you properly gap them (file them to fit your bore?) and were they installed in a staggered manner with the rings facing 180 degrees from eachother (open ends) and such?

Honestly I think your in for a set of rings and if that is the case then your gonna want to have the bore checked for size to make sure its not egg shaped and make sure you hone the bore if its not egged-your going to need to create those scratches in the cyl wall again Im sure.

Its alot to take in, hope it helps. Report back after you have more info.

[400ex_alldayy]

oh ****, i think i forgot to stagger the ring gaps, i did file them to fit tho
fml lol
thanks alot tho man, big help

[400ex_alldayy]

if it were the jets and it is smoking as much as it is, it wouldnt run very well tho right? cuz it'll idle and ride good
sorry never done alot of jetting before

[CJM]

Well what happens when you add things like a high compression piston or bore the cylinder larger is the engine now needs more fuel. If you dont have the proper jetting it runs lean due to lack of gas and you basically cook the inner cylinder.

Now, if it were just jets and running extremely rich (to much gas) then the smoke would be more black and you would wind up losing no oil really.

2 signs that point to bad rings, whitish smoke all the time and oil loss.

[400ex_alldayy]

oh ok, im thinkin it is the rings gaps, all the other pistons ive done on sleds had little tabs to place the gap where it should be, as far as i remember i didnt stagger the gaps, thanks alot tho man big help

[CJM]

Good luck with it, you still might have a problem but its worth a shot. Re-hone the bore while you have it apart .

You want to stagger the gaps on most pistons by 180 degrees. Depending on amount of rings I usually put the top 2 rings 180 from eachother the front of the piston and the oil ring to each end of the wrist pin. Anymore rings and I stagger them inbetween the others.

[400ex_alldayy]

ok, so i put it all back together with the ring gaps staggered and the cylinder looked great, still had the lines from when i honed it before but its still smoking
ive put the recommended jet from my dynojet kit and it runs good, doesnt stumble or anything really and the plug is brown when i checked it
i have no clue why its still smoking but it does it a bit when i stab the gas at low rpm and after i rev it out and let off, i have a compression tester but it doesnt come with the right thread type for the ex plug so thats my next purchase but im sure it will have dece compression cuz it feels faster than when i had the stock piston and cam in it
i kinda think my head could be warped a lil? its not leaking oil on the cylinder from what i can see tho
im out of ideas lol :S