1980 Kawasaki KDX80 back to life

[nobog]

KDX #2 was missing the cage for the air filter - I can't find one new or used (someday one will show up on eBay) but for now I had to do something. I made a new Delrin base and found an air filter that will work - and of all things - its a filter for a 1200 Harley ! I'm not sure how a Kawasaki and Harley will mix but for a temp fix it will have to do. These are readily available and cheap - like $5 each cheap. I then made an acrylic cover thats just held down with a couple of wing nuts.

Tank is being painted so that will be a few weeks before that is ready with the new decals.

 

[nobog]

So here is the bottom of the tank, I sent it out to:
Motorcycle gas tank repair and restoration (gas-tank.com)
Basically they cut the bottom of the tank out and fix the rust (and the leaks) from the inside - then weld it back up.
It'll be a couple of weeks before I put the decals on as I want the paint to take a good set.

 

[nobog]

OK, that took a bit longer than I thought....
I could not get it to fire and went through all the usual stuff - and long story short - there was a score in the cylinder and I thought I could live with that but no way - luckily I had a NOS cylinder and piston and that did it. I can always fix the old cylinder sometime. So .. as per usual this cost way more than it should - but that's the price for progress I guess. I had to make my own side number plates as anything remotely original is NA or has been significantly trashed. Aftermarket from fender but an original rear from KDX #1. New bars, shift shaft, shift lever, redo the seat and a few carb parts. A "universal" front number plate, and there you have it. Not sure what's next but something will eventually make it home to the shop.

First photo the "artsy" shot then the rest.

 

[RM_guy]

Very nice! Too bad about the scored cylinder. Just looking at that makes me want to rip it around that field of yours!

 

[bweighmaster]

Nice work , can I send you a bike ? I'm kinda on the lazy side in my old age ...

 

[King7Two]

Man, That's fantastic.

 

[nobog]

KDX #2 update:
I noticed a leak coming from the case – I don’t like leaks, so let’s figure this out. It seems to be coming from the plastic magneto housing – but there is no oil behind there – odd – closer inspection reveals it is coming from one of the bolt holes that hold the plastic cover on. Back up a bit – when I took this thing apart I remember a noticeable amount of red high-temp silicone on one of the screws for the magneto, I didn’t think anything about it as these old things have silicone everywhere, I just figured it was part of a gasket (that was missing of course). So more silicone it is – that plugs that leak but was curious as to why it would leak there.

Fast forward to a ride around the block – I know that sound as the bike comes to a halt – no compression. Crap. I have compression – at least on the top end as that’s all new. I have spark and gas so it has to be a crank seal or the mating surface for the crankcase. Is it related to that oil leak? OK, let’s take it apart, that way I can figure out what’s going on with that leak.

I F**ed up as the seal on the right case for the crankshaft is, well, messed up. Must have been upon assembly, from the outside the seal looked perfect but somehow the little coil thingy got smashed. I will assemble the case and THEN install the seal this time.

Now let’s figure out that leak – so you can see in the photos there is a small hole. There isn’t supposed to be a small hole. That’s the bottom of the screw hole for the magneto cover. Was it like that from the factory? Did someone try to tap it deeper and run the tap through? One will never know. That will get welded up for a sure fix. It’ll be a couple of weeks before up and running so a final (I hope) update at that time.

 

[RM_guy]

Nice investigating work there!

 

[nobog]

So that should wrap this up - a couple mile test ride and everything seems to be in order, now to just find the next project...

 

[Kawi89]

Hi I have a 82 kdx and I am rebuilding it. When rebuilding the crank assembly is it true you need to balance it and make sure it’s true again……also is this still reusable

 

[Okiewan]

When rebuilding the crank assembly is it true you need to balance it and make sure it’s true again

You may not have to, it was balanced at the factory. However, you REALLY should get it checked at a shop, they can tell you if it's in spec.