1987 KDX80 Rebuild

TheGriz · Post by **TheGriz** » 09:41 pm Apr 24 2015

I picked up this 1987 KDX80 for $200, thinking it just needed rings and a few odds and ends. It is never that easy! My neighbor's son has been helping me in the shop and this was a great project for the two of us to tinker on.

The day I brought it home:

TheGriz · Post by **TheGriz** » 09:46 pm Apr 24 2015

I found so many surprises:

This previous "fix" had layers of silicone and bondo on it, but was still leaking.

This is what was under all the silicone and bondo:

Fixed the cases properly. Tig welded a big land area to create a new tab and filed it all down nice and flat.

TheGriz · Post by **TheGriz** » 09:48 pm Apr 24 2015

We found the clutch pressure plate was chipped. It looks like someone tried to pry the clutch out with a screwdriver. My partner is installing the new clutch:

TheGriz · Post by **TheGriz** » 09:58 pm Apr 24 2015

The previous owner "fixed" the leaking forks by piling rtv around the fork tube and slid the boot down over it. LOL

Forks have new seals.

A pile of other parts and work completed:

Stripped and sanded down the frame
Bew ball bearings for the steer tube.
Cylinder Honed
New Wiseco piston and rings
New Stator - Had a very weak spark
Used wheels found on ebay - New brakes
New KX80 Carb
New Boyesen Reeds
New handlebars
New throttle-tube assembly from a KDX220
The plastics were sanded down and cleaned up a bit.
Used airbox found on eBAY & new UNI filter
New tires
Used side plastics found on eBAY. White vinyl added to the number plates
Fabbed a new chain guide out of aluminum
Made a chain slider work...

Probably some other stuff too... too much to remember

TheGriz · Post by **TheGriz** » 09:59 pm Apr 24 2015

TheGriz · Post by **TheGriz** » 10:00 pm Apr 24 2015

Finally! I had started to give up hope that this bike would ever run again.

Post by **KDXGarage** » 01:57 am Apr 25 2015

WOW! Good job on the rebuild! It looks nice!

Sullyfam · Post by **Sullyfam** » 06:47 am Apr 25 2015

Sweet and that's one happy neighbor!

Sent from my iPhone using Tapatalk

TheRadBaron · Post by **TheRadBaron** » 07:14 am Apr 25 2015

Looks great. It gives me some motivation. I happen to be rebuilding an '87 KDX80 at the moment as well. I bought mine for $80, though it needed a lot of work. I'm not doing as thorough of a job as you are, either. I just want to get mine mechanically sound and reliable for family use. My wife wants to start riding trails with me and I know she's intimidated by tall bikes so the KDX80 might be a good starter trail bike for her until she gets more comfortable. She's 5'6" and about 120# so she might be a bit big for it but I think she'll like it that way.
Once she outgrows it I have a lot of young nephews and friends' kids around that could use a good trail bike to learn on. Mine has a sleeved cylinder that looks to be well done so I had it bored 0.5mm over and put in a Wiseco piston. The crank seemed good so it was left alone but I split the cases to change the crank seals and all the other oil seals. I should have it back together within a few weeks.

TheGriz · Post by **TheGriz** » 10:47 am Apr 25 2015

Thanks! I had fun working on this little KDX. After selling my 2003 220, it was nice to still have a KDX in the garage.

This had a sleeved cylinder as well. I was going to have it bored as well, but after a quick ball-hone, most of the worst grooves were gone, and I decided to go with it. I'm glad I did! She makes good compression and fired on the second kick.

It is much shorter than the 99' KX80 that I have. I'll try to take a side by side shot of the two, but at 5'6" this thing would be a bit small. It would be good to learn on at least. More mild power and easier to get a kid's (or small woman's) feet flat on the ground.

Kawai man · Post by **Kawai man** » 09:37 pm Jul 11 2018

what air filter did you buy? and carb?

I'm trying to get a kdx running and just wondering what you used.

KDXRIDER.NET

KDXRIDER.NET