KDXRIDER.NET

I'm having some problems on the '89 KDX I recently put together. Whenever it starts up for the 1st time of the day it revs very high and smokes a **** load, and slowly returns back to idle speed. I understand that throttle response and smoking will be bad until fully warmed up, but it's terrible on this bike. And even when this bike is warmed up, throttle response is still kinda sluggish and it still smokes quite a bit. What could be the problem?

Air leak? Jetting? Fuel? Rag in the intake boot?

add bad crank seal to the list or leaky head gasket? easy to check: are you using more tranny oil (crank) or coolant, does the smoke smell sweet (burning coolant)?

Air leak: couldn't find one
Jetting: 155 main 45 pilot, ran like crap with a 42
Fuel: fresh, 93 octane mixed with Motorex fully synthetic 2t
Rag in intake boot: havn't tried that but I turned the air screw all the way in and it still idles, I'm pretty sure that's not normal
Main seals: I remember taking off the magneto and stator and saw a leaky seal, so I suspect the other is bad as well. Could it be THAT bad to where it affects performance this much?
no apparent drop in coolant level, tranny oil level slowly dropped as a result of a leaking clutch cover gasket
Head gasket: in new condition. Even sprayed around it while running just to make sure it's still good
exhaust definitely doesn't smell like my other KDX, don't know how to describe it

KDXrider1989 wrote: Main seals: I remember taking off the magneto and stator and saw a leaky seal, so I suspect the other is bad as well. Could it be THAT bad to where it affects performance this much?

You are lucky you have not burnt it up yet

yikes, guess no more riding until I tear into it to get those damn seals replaced

Yup. replace the bearings while you're in there.

took apart the carb and cleaned out everything with kerosene and compressed air. I found out that the little tang to adjust the float height was previously adjusted way too rich, so I adjusted it back to stock setting. Started up nice and smooth, seemed to be smoking less also but it's dark outside so I'll need to start it up again tomorrow. Another thing, I took the flywheel cover off and found that the main seal wasn't leaking to the point where i could see oil on the bottom of the casing. The picture that's posted was before i even ran the bike