81' KDX 420 Carb Adjusting After Parts Soak

[gunnershank]

Hello, This is great! I finally found a forum with somebody that is in the same boat as me. I recently purchased a 420 KDX 1981. I rescued this bike that has been sitting in the guys backyard for eight years. I took it apart repaited it, put a new sparkplug in and presto a new bike. Only I'm noticiting a few more problems with it than I bargained for, for example, the rear shock is shot and the front in on it's way. I ran the bike up a mountain and it started to rev like crazy so I shut off the gas and wiated for it to die. The throttle cable was stuck because of melted plastic on the insert. I just put a new cable in that cost me 40 bucks and it worked for about five minutes and after I took it around the block it started to rev like crazy again, which in turn is driving me crazy! I know my carb needs some adjusting, and I think it's sticking somewhere inside the carb. Just wanted to know if that is what it is. Maybe it's an easier fix. Please help.

Serge

 

[gunnershank]

The needle is on the top notch and the cable adjuster in the middle of the throttle cable is almost all the way screwed in. The mix is 32:1. I did notice that the guy that I bought it from put an after market air filter that is way too big for it thus making the plastic stick out a 1/4 in. I don't really know too much about 2 strokes, if air is really important or not. I noticed you were talking about reeds earlier, should I take mine off and clean them or replace them. Any info would help. Thanks.

 

[gunnershank]

Here is the pic of the Beast!

 

[gunnershank]

The kickstand rusted off that's why it's on a bucket

 

[glad2ride]

NEAT!! Some will be surprised to learn there were KDX's before 1995. :-)

Look on the Kawasaki site for the parts microfiche. It will be a great help!

 

[samiam]

I love seeing these older 400's, 420's, and 450's. I just do not see many of them around New England. I rode an older twin shock 400(?) owned by a co-worker once. The motor was very strong and torquey, but the rear suspension felt positively ridged!
I still enjoy looking closely at every one that I come across. I agree that the emblem on the head is a nice, unique feature, and should be preserved if possible.
I enjoy looking at older Yamaha IT's as well. The white IT's seem to be more rare than the white KDX's.
On any older dirt bike, one of the first things you should inspect closely for is air leaks around the carb boots. You should replace the crank seals as well, as they tend to be neglected due to the work involved in replacing them. Either of these things can cause severly lean conditions, which can cause "revving" and great damage to your engine.
Carb boots (on both entry and exit sides of the carb) are usually dry rotted or cracked beyond repair, although sometimes you can get by for a while with a coating of silicone sealant.

 

[glad2ride]

Yes, do check the boots.

The IT's are cool, too.

 

[gunnershank]

Thanks for the advice, the carb boot that goes into the head has silacone all over it from the previous owner. I'm gonna replace it and clean the carb really good and see if that fixes the problem. How about the needle? Should I leave it on the top notch or move it to the third notch as previously described? Thanks for your help.

 

[glad2ride]

I would check that air filter fit, as well as the reed condition, as it is almost 30 years young.

 

[gunnershank]

Alright, I took the carb off and cleaned it really good. I adjusted the throttle cable and everything seemed fine untill the bike just died out of nowhere. I sat there and kicked for a few minutes and gave up. Took the tank off and drained the fuel and cleaned up the fuel valve which had a badly corroded mesh in it. Then I decided to check for a spark and Bam! No spark. Great just more money to dump into it. I took the tank off again and looked at the coil and it is pretty rusty. Is that the problem or could it be worse and be in the stator?

 

[glad2ride]

I'd try to clean the coil connections to the frame before I got too deep into it. It's an oldie, but goodie and will need some TLC.

 

[gunnershank]

I know i shouldn't get upset over this bike, it's not it's fault, It is as old as I am. The connection is not rusty, the coil itself is rusty. I think I'm gonna start with a new coil and go from there. Just sucks it's keeping me from riding :p . I live in southern WA and the weather has been really really nice.

 

[gunnershank]

So I double checked the spark today and it is deffinetly not there. I took the coil off and found a little problem with it. I'll let the picture speak for it self. I just hope that it's the problem and not the CDI, because it's about a three hundred dollar difference. :yikes:

 

[gunnershank]

Any advice would help. But for now it's off for the hunt for a cheap coil.

 

[glad2ride]

swollen??

missing a wire or more??

What am I missing? I am not familiar with such an aged beauty. :-)

 

[gunnershank]

Does anyone know if the Kill Switch is a loop or a open circut?