1994 kdx125 spluttering

[roblemon69]

hi
my brother has just bought a 94 kdx125 its only had a engine rebuild around 200 miles ago and it sputters on the highmid-topend revs and smokes quite a lot all of the time. it starts to build up power then it just goes flat and splutters.if you mess with the throttle sometimes you can almost get a powerband like my old kx but then it dies back down to around 5-6000 rpm and splutters.we have renewd the plug and took the exhaustside kips cover off and found the rod from the bottom end not connected to the exhaust valve thing?? so we fixxed that and it sounded like it was sorted when started and reved.but when ridden it was a felt more stronger than before
but still the annoying sputter still remains.
can anyone help?

 

[QKENUF4U]

sounds rich on top , play with needle first. (lower the needle one at at time)

 

[roblemon69]

tryed the needle in all place and no diffrant ?
any more help anyone

 

[QKENUF4U]

have ya made sure the power valves are working/opening correctly ?

 

[twoslow]

check your float level as a high setting can give the same problems as rich jetting

 

[roblemon69]

found out what it is the bloke my little brother got the bike from is a lying f**k*r who just fitted new gaskets to an old engine and said it was rebuilt as it eats engine oil (not two stroke) and when it gets quite low the smoke from the bike clears and the power comes back intill you top up the the oil we think crank seals or something else has gone.unless any one has any other ideas

 

[Gaffs-09]

i had exactly the same prob! ive just split my motor and bought new crank bearings and seals, which seem to have been gone. ill let u know how it goes

CHeerz