Just Got a KDX 420 need Help !

[kevstar1212]

Hello im new to the site here but have dealt with a few forums and you guys seem pretty good. So anyway i don't know a whole lot about bikes (Always had trucks jeeps and quads) but i just bought an 81 KDX 420 . From what i can tell is pretty rare. thought i got a p[retty good deal on it $200. well its suppossed to just need a $20 Clutch bearing. but im sure it will need more than that. i read something about black goo from whre the exhaust comes out and it needign exhaust roller bearing? so my question is where can get started off with some service manuals ? anybody got a pdf or a good site? also what all do i need to check? gonna start tearing into it today ..... Thanks and sorry for the new guy post...

 

[Matt90GT]

So you need help finding a cliff for that bike????

Seriously, where would you go if you needed a Jeep manual? Ebay, Maybe the Jeep dealer. So apply that to your Kawasaki -- Ebay, Kawasaki dealer

 

[julien_d]

First off. Sweet!! I'd love to get my hands on a 420. You are correct, they are pretty rare. I'm almost sure they were only made for 1 year...

Quick ebay search...
http://shop.ebay.com/s.html?_nkw=kd...odkw=kdx420&_osacat=See-All-Stores-Categories

You can probably get it through kaw too. Might cost you a couple bucks more but you can be sure it's new and complete.

A picture or two would be greatly appreciated! In my opinion I'd check EVERYTHING. Get the service manual, tear it completely down, and start checking/replacing bearings and moving parts as needed.

 

[kevstar1212]

sorry matt i knew i could get a hard copy but i kinda wanted the pdf so i could download it now. I will get pix up soon..... but don't be expecting much. . . . I get the feeling the PO wasn't a very good mech. everything is zip tied and bike is kinda rough. then again its almost a 30 year old bike.... so who knows.... thanks

 

[kevstar1212]

hey just thought i would give ya all an update. i cleaned carb filled her up and played around with the electrical and got her to fire up. took her out for a really quick spin and i couldn't believe the power. came up too easy.... IM SCARED OF IT!!!! haha but i had no clutch and no brakes so i guess i had good reason to be....

 

[bultaco4ever]

Clutches and brakes are overrated anyways :)

 

[Patman]

So was the idea of a pdf that you could download now also because you were hoping it would be free?

 

[wake_rider]

When it's running, does it smoke really bad and smell a little like a burning field? If so, be careful. It might be running under the influence... :laugh:

 

[sr5bidder]

Congrats on the kdx 420

I had a chance to get one for $50 this summer when driving up to West Virginia to ride the Hatfield McCoys trails...it was near Mamoth Cave KY

 

[reepicheep]

KDX 420 huh. Didn't even know there was such a creature. Sounds scary... monstor motor combined with 1970's suspension tachnology :0

 

[kevstar1212]

ha ha. . . . well i've still got quite a bit of work before i can go test out the suspension. . . . an i wouldn't mind paying a couple bucks for the PDF . . . I have bought ones off ebay for my quads before. . . just pay like $5.99 and its sent to you in an email within like 5 mins of paying . . . . really quite nice. . . . so i thought i had read something about black goo coming from the exhaust? mines got quite a bit coming from there .... Should i be worried? also how can i get a good idea of what kinda shape the motor is in ? don't know much about two strokes (first time buyer :) Compression test? how much should it be? and anybody got a clue where i can get the bearing for the clutch pusher holder? dealers tell me its discontinued?

 

[sr5bidder]

for the bearing just measure the O.D of the hole and the O.D of the shaft that goes in the bearing then guess the thickness and search ....like 19x12x10

 

[mike koenig]

Hi Kevstar,
I too just purchased an '81 KDX 420 for a complete resto. They are relatively rare, only made for one year. It became a 450 in '82 and then was discontinued. Most parts are available, but unfortunately not the piston rings. The piston is, however, as well as gaskets, etc. I use bikebandit for my Kawasaki parts supplier, VRM Racing for seat covers and tank decals, DC Plastics for plastic (overall dull matte finish but good quality), and ebay for everything else. Keep looking on ebay for parts, it taskes persistence and sometimes a general search- for example if your tank is stained brown, look under "kawasaki tank" or something like that for mislabeled stuff- I did that and found a really nice tank for $2! If your other plastic is chalky white or faded dark green, as it tends to, you can restore it to good condition by scraping with a razor blade down to good plastic followed by sanding up the 600 grit.
I'd definitely take off the top end- the piston to bore clearance was really tight, 0.002" on those, and ring end gap should be under 0.030". If the crank big end doesn't have any noticeable sideways twist or end play, it'll probably be fine.
The suspension can actually be made to work pretty well, if you send the rear to Works Performance and play around with fork oil weight and levels in the front.
Most people are surprised at how well a properly set up, decent quality post-vintage bike works, but it all depends on how much you want to spend. Honestly, they are super easy to work on, if you need a manual I can email you scanned images of specific sections, but being old bikes they really need a compete going through to be decent.
Sorry to ramble a bit, but my passion is post-vintage dirtbikes- with the exception of the '85 M-Star 500 I just bought to restore- disc brake (front) and water cooling- now that is getting pretty modern!
Let me know if you have any questions, I'd be glad to help if I can- love to see those old beasts flying through the woods.
Mike K.