1994 KX250 Rebuild

The very first lap on the track I had a massive flashback in time,so many good memories with mates back in the 90s on 2 strokes.

A few issues came up pretty quickly. The brakes are terrible, the forks are so soft they would compress and not rebound under brakes,at the end of the day they were leaking. I could feel a bit of backlash through the kickstarter/clutch.

The motor has a great hit of the bottom and snappy midrange it definitely doesn’t have the top end/over rev of a 90s Honda.

Regardless of the problems I still had an absolute blast.

After doing some more research on this model. I got in touch with another forum member called Kidkawie who restored one of these back to like new.

He gave me a lot of information on what to look for particularly cracks in the frame.

I checked out the backlash issue with the engine and the primary gear was so sloppy it was moving backwards and forwards plus sideways. The previous owner used a aftermarket crank and the machining tolerances are garbage.

Pulled the motor out looked for cracks and yes.Both lower engine mounts cracked,footpeg mounts cracked.Previous owner cut through the lower linkage bolt(must have been seized) and cut into the frame so the lower linkage was sloppy.Subframe also cracked,the powder coating hid all of this.Just Awesome work.

So after one ride I completely stripped the bike.

I have a mig at home but not a tig and the frame needs both.One of my friends has a race car fabrication business with everything which is lucky for me.The main issue was fixing the frame at linkage pivot.I spent hours grinding and file finishing it flat before welding in thick washers to get the frame back where the linage bearing sleeve was tight.You can see the gap after the previous owner cut into the frame.

The frame was welded up everywhere.

I dummy fitted the suspension and made sure everything was good.

I got paint matched up closer to the UFO plastics,so the colour is a bit more vibrant than oem green.

Thanks,the previous owner had it powder coated.

I stripped the engine because of the crankshaft spline was machined undersize. This was causing so much play in the kick starter/clutch basket.There were other surprises inside the engine of course.

How did he even tighten these?

I picked up an oem crank and had it rebuilt with a pro x rod and got the cases vapour blasted.The cases are good gearbox is good luckily. I used oem crank seals with Jap bearings.

The Kawasaki engineer who designed this engine must have had an issue or beef with the Kawasaki engine builders.😂😂 A bit of a pain to build.

First off you have to install the crank seals,then freeze the bearings and heat up the cases install the bearings.

Then freeze the crank,heat up the inner races on the bearings not to hot because the seals are in.

Assembly the motor,then centre the crank in the cases because the primary gear drive only has a circlip not a bolt which normally is torqued up and pulls the crank against the bearing and it’s then central.

Hopefully with all the repairs it doesn’t crack again. I also painted the frame instead of powdercoat so I can see everything.