KDXRIDER.NET

I just got my 1991 KDX250 back together, and she's still a smoker.
It seems to me like it's too much white smoke (with a light tint of blue). It smokes at idle, and it smokes more whan I rev it.
Can I drain the tranny oil and let it idle to see if it goes away, perhaps ruling out crank seals?
Can i drain the coolant and run for a cupla minutes to rule out head leak (Or is this too dangerous even for a short period)?
The bike has a new piston and rings. It has 190 compression.
It has a new head gasket (cometic).
I'm running amsoil at 40:1.
Jets are 38 pilot, 160 main and 1368 needle on the top clip. Air screw out 1 1/2 turns.
It idles and runs fine, except for the smoke.

Main sounds big...

White smoke is water.... what is the temp there?

Its about 25 degrees outside, if that's what you mean.

Re: 'Can I drain the tranny oil and let it idle to see if it goes away..'

No.

Well, you CAN...but it would be a foolhardy move.

You can test for leaks using a leakdown tester device. Basically, attach a pressure/vacuum guage through the oil filler plug (as an example), run the bike, see what happens. Natch...the breather needs to be blocked off. It would help to have a baseline (a reading done when it worked fine). You can use it to guage changes you DO make, too.

Does the bike LOSE tranny oil? If it's enough to show in the smoke, it will show as a loss of fluid.

That said, as Inda said..white isn't tranny oil. Coolant leaks will show as 'white'..and it will smell sweet, too.

A 2-smoke may well have 'white' smoke..especially when it's cold..and 25º is cold.

If you have no other telltales (fluid loss, sweet smell, steam-bathed looking sparky plug), don't worry about it.

imo and all that extraneous baloney............

Sometimes KDX's just smoke a lot

http://video.google.com/videoplay?docid ... 9138328282

Thanks guys. Thanks for the feedback. And nice video!
!

Well, I decided to take off the head to make sure everything looked good anyway. It did, and I saw no evidence of head gasket leaks.
I buttoned it up with a new head gasket -- and promptly snapped off a cylinder head stud! I was using a torque wrench set to 18 ft lbs, so either my wrench is no good or the stud was bad.
I twisted it out with some vise grips, and got a new stud at the hardware store of the exact same 8X40 size. (it's just steel, right?) So i'll get another head gasket and try again. (I understand they are no good once they are squished)

The same thing happened to me when I did my fork conversion.
if your torque wrench is as good as mine (read cheap), I always keep it at the lowest setting when not in use and when I do use it, I always go 5 lb at a time till I reach the correct torque. If I feel like it should have cliqued already I start over, hope that makes sense.

As for the head gasket I heard some re-use them after applying some copper spray or sumthin like that but never tried it myself.

Wilf

I have reused them... get the copper gasket spray if you don't want to buy another gasket.

If you use a gasket spray..take note of the small round hole in the gasket that 'mates' with an ellipsis kind'a shaped hole in the cylinder/head. Try to remove the sprayed material from the gasket in the ellipsis area. When you don't, that part of the gasket exposed to coolant will take the sprayed material off..to float around your coolant system...get stuck on the rad cap gasket.

I don't know that's a big deal...I've NOT removed the overspray most of the time (and then found the floaters) and don't know that it causes problems...but...metal floaters in the coolant system doesn't seem like a wonderful thing to me.

Good thing you got the stud out! Sometimes they don't come out so good.

Even a good torque wrench loses it's 'tune' after awhile. There are tool shops that calibrate wrenches...........

I have reused head gaskets one time coating both sides with copper coat.
Never had any problems with many miles.

Just don't use Orange High Temp Silliycone!

I never thought I'd ever hear the end of that one!

I just use a very thin coating of high-moly grease.....stuff made in the 50's I would guess.

Now, someone (anyone) is free to tell me why that is a bad idea

I know folks who use paint.... Seems to work.