my 400 ex is smoking

[4strokemadness]

hi ,i need some help ,i have an 05 trx 400 ex and it is starting to smoke a little is this something that can be fixed by adjusting valves or is it possible my valve guides are going bad? i just picked this bike up a week ago and now this b.s. it does not seem to lack any power but i dont want to hurt the motor any any info will be gladly appreciated
thanks guys

[90vfradam]

do a compression test , see if rings are good.

[FIRSTResponder]

your valve stem seals could be worn does it smoke all the time or just when it starts up?

[4strokemadness]

its the weirdet one ive encountered (im a die hard 2 stroke man-- 3 blasters)
its white smoke !the other day it was smokin some the next day not a single bit of smoke,the oil has a bit of a fuel smell to it,its an 05 and all stock except tires and a slip on .im fairly mechanicaly sound and would assume that its not much diff. than a car motor im gonna pull a compression check today and see where im at ,i was told it could be a carb issue (floats sticking) when riding wot in 5th gear and let off i get a backfire (maybe timing)

[FIRSTResponder]

so is the smoke white??

[4strokemadness]

white smoke!!!!!! yesterday i started it up and not a bit of smoke! fuel smell in the oil , im kinda leaning towards carb(floats, fuel metering) she will backfire but only after WOT in 5th gear no other gears backfire after letting off

[Here 2 help]

A backfire after WOT in 5th gear is not a sign of anything wrong espeecially if the exhaust has been modified from stock. Honda street bikes and some off road vehicles have carbs with an "air cut valve". The valve cuts the air to the idle circuit during deceleration, enrichening the fuel mixture, to prevent backfiring in the exhaust. If the exhaust is modified, it reduces the back pressure and increases flow which in turn leans the mixture and may cause backfiring.