1991 kx250 smoking & bogging ?

[timberwolves]

Getting the bike back together just waiting on the front forks. Had it running with new plug, air filter, fresh gas mixed at 40:1, anti freeze & oil change. I had to change the PWK carb out as the original was completely trashed and deteriorated. I replaced the carb with a used Kehin PWK with # 58 slow jet, # 160 main jet & N85C jet needle in the middle position. I believe close to stock. The bike idles its best with the air screw out 2.5 turns. The crankcase, kips cover, clutch cover & water pump gaskets were changed as well. The crankcase had a crack in it as well as the clutch cover. The bike has a FMF Gold Series pipe on it and I think the silencer is stock, no markings on it at all. I cleaned the pipe, silencer & repacked it. When running it smokes & has a mid range bog ? Seems to be very oily at the end of silencer. Any help would be great. John.[/URL][/img]

[sandblaster]

Do you have the video on your computer?
If so you will need to post it on Youtube or another host service and then post the address here.

[timberwolves]

I have it on photobucket ?

[sandblaster]

What's the address?

[timberwolves]

Video showing white smoke, I hope its not the crank seal ?
http://i272.photobucket.com/albums/jj185/timberwolves_bucket/023.mp4

[timberwolves]

 I think I finally figured out how to post pictures.  Just waiting for a few more parts, front forks in the process of being rebuilt. Had the frame & foot pegs powder coated, cleaned up the swing arm and the rest of the bike. Pressed in new steering stem bearings and a bearing on the rocker arm that was trashed. New chain and sprocket as well. In the picture I was just checking the color of my rear fender to the frame, the orange tape is holding the rubber gas tank bumbers until the glue sets. I'm having some issues with the bike smoking, as seen in my above post and video.
http://i272.photobucket.com/albums/jj185/timberwolves_bucket/016-1.jpg

[sandblaster]

What elevation are you at?
What position is the needle clip?
Also I think your a bit fat on the pilot as well but let's get the clip position first.
Your bike should idle best at about 1.5 turns out...
If your 2.5 turns out it's telling me that too much fuel is being sucked into the engine.
Clip position, Pilot to fat, or both..
Let me know.

[timberwolves]

The jet needle is in the middle position third from the top, my elevation is 10' above sea level.

[sandblaster]

Before you do anything else, pull your plug and check it out (If you haven't already).
My guess is it's black and oily.
Clean it up and reinstall it.
I would move the clip up the needle one position so that the needle is further into the main jet.
This won't help your smoking at idle but it will help your midrange.
I would put in the next smallest pilot jet then run the bike again.
You may have to adjust the air screw.
In fact, you want to be running the air screw at about 1.5 turns out.
So chances are the next smallest size pilot jet won't be right just yet.
But, pilot jets are cheap and it's better to make small changes and verify how it's running by checking the plug.
Making a big change without verification can lead to major engine failure... so be safe, not sorry..
I'd try a 55 pilot next..

[timberwolves]

Sandblaster thanks for the replies and info. Yes the plug is black and oily. I will move the needle jet up one position. I was looking at the FMF site and it recommends I should be using a #52. In the morning I will run over to my local shop and grab a few jets. The only way I can get the bike to idle was to remove the locknut and turn the adjustment screw all the way in, like the adjustment screw needs to be a bit longer. Also the slide is a #7, which I believe is stock. John.

[sandblaster]

There you go.
I figured a 50 or 52 would be good but small steps are safe especially when it's not your bike
You should notice a lot better throttle response and less smoking..
Let me know where your air screw ends up after you put in the new jet.

[timberwolves]

So I changed the needle jet to the 2nd from top position. I also changed the slow jet to a #55. My local shop didnt have a #52 but they  had  #48 & #45s that I picked up but didnt try those. I think it still running rich. The bogging seemed to get a little better, but when I hold the throttle the bike blows white smoke bad. I think I may have a leaking crankcase seal, but have not done any testing yet. Any thoughts ? John.

[sandblaster]

Are you loosing water?

[timberwolves]

Doesnt appear to be losing antifreze and its still clean, not oily. The same with the crankcase oil clean & not milky.

[sandblaster]

Get your jetting finished and watch your fluids closely.
I still think you way rich on your pilot.
Here is my first heat cycle on my K5SM
http://www.youtube.com/watch?v=UZZHiDC0D4Y

I went down 2 steps on the jetting and this is the 3rd heat cycle.
http://www.youtube.com/watch?v=aylQHPS3KNg

Thanks to Motorrad I finally got the jetting sorted... 4 steps lower then I started...
I don't have a video but it's a thing of beauty