Posts
21
Joined
7/13/2022
Location
Spring Creek, NV, USA
Edited Date/Time
7/24/2022 5:25pm
This project is about 99% complete, but I wanted to share the journey of the past 2 years that has brought this bike to where it is now. I will make several posts documenting the build. The end result won’t be for everyone and that’s okay with me. I hope you enjoy!!
A little history….
It all began with my brother building a new house (weird, right). I’ve been an electrician for 20 years working in all fields from residential to heavy industrial in mining, and gas and oil. He asked if I would help him out and wire his house for him. I was reluctant, but said yes since he is family. I didn’t want him to pay me so long as he helped out and paid for all of the materials, which he did. In the end he still wanted to get me something to show his appreciation. So, I had been looking for a KX 500 for quite some time and just happened to find one located about 4 hours away for $1500. It looked decent, so we made the drive knowing that any 500 for this price probably has some issues. Not the case with this one. It fired right up and ran great. I mean, it was 32 years old, so of course it has some minor issues, but overall it ran and functioned as it should.
The plan was to enjoy the bike and just ride it while slowly making some upgrades and changes to fit what I though it needed. The more I rode the bike, the more apparent it came that the engine was a little tired. It ran fine, but I could tell it was lacking. I decided to pull the engine and go through it while doing a top end rebuild, maybe the bottom end depending on the condition of the crank and bearings. So, the tear down began….
Stay tuned for more…
A little history….
It all began with my brother building a new house (weird, right). I’ve been an electrician for 20 years working in all fields from residential to heavy industrial in mining, and gas and oil. He asked if I would help him out and wire his house for him. I was reluctant, but said yes since he is family. I didn’t want him to pay me so long as he helped out and paid for all of the materials, which he did. In the end he still wanted to get me something to show his appreciation. So, I had been looking for a KX 500 for quite some time and just happened to find one located about 4 hours away for $1500. It looked decent, so we made the drive knowing that any 500 for this price probably has some issues. Not the case with this one. It fired right up and ran great. I mean, it was 32 years old, so of course it has some minor issues, but overall it ran and functioned as it should.
The plan was to enjoy the bike and just ride it while slowly making some upgrades and changes to fit what I though it needed. The more I rode the bike, the more apparent it came that the engine was a little tired. It ran fine, but I could tell it was lacking. I decided to pull the engine and go through it while doing a top end rebuild, maybe the bottom end depending on the condition of the crank and bearings. So, the tear down began….
Stay tuned for more…
We are in July of 2020 at this point, right during the height of COVID. The engine is torn apart and the bike is in pieces, as you can see. Since I already had the bike completely apart except the front end, I decided I’d get the frame powder coated and replace bearings and such. I mean it is a 32 year old bike.
July 27, 2020…. I get a phone call that my dad has passed away after a very long battle with MS at the age of 58. As you can imagine, this project gets put on hold. My dad bought me my first motorcycle when I was 4 years old. He and my uncles took me to the races for as long as I can remember. When I got my first bike, I remember that he had a 1987 KX 250, pretty much identical to the 500 I now owned. This project has now taken on a new meaning for me…. My wife told me, do whatever you want with this bike because I know what it will stand for. With that being said, and after some time, I really began to research and see what I could do with this bike. My dad loved Kawasaki’s, old and new. He loved to watch all the races and just talk about how the sport has evolved over the years. I came up with what a lot of guys have done already, and decided to make a hybrid bike of sorts.
I settled on a complete engine rebuild done by someone that specializes in these engines. I would then put the engine into a 2001-2002 KX 250 frame to make the geometry better. And top the whole thing off with upgraded suspension and a restyle kit (yes, I know they aren’t for everyone) to modernize the look.
The cylinder was in great shape but it was sent off to Millennium Technologies to be replated before the porting work began. The head had to be replaced as it had been previously cut and would not work for our end goal of having a compression release installed. I ordered a new Keihin Airstriker 38mm Carb for the engine that would be bored out to 40mm.
The clutch side of these engines is a one piece cover requiring you to remove the entire side of the engine including the kickstarter to access the clutch. So, I had Growler Racing mill the side case and install a removable clutch cover from a 2018 KX250F. This makes things much easier.
The engine was getting worked over and coming along nicely. I say that now, but it took quite a while for the work to be done, understandably so. Matt (Growler Racing) does this as a side job to his real job. He also has a family and loves to ride, so my engine was done as time allowed, which I was fine with.
There is a little bit of forming that needs to be done to the gas tank to make it accommodate the height of the engine. I also had to switch to a short spark plug to make a little more room under the tank. It’s a tight fit, but everything does fit in there with some tweaking and fine tuning.
Before I sent the frame out for powder coat, I needed the engine back to mock it up and make sure everything fit.
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After talking with several people about what to do with the suspension, I finally settled on using the stock suspension while adding a set of sub tanks. Everything was shipped off to Enzo Racing so they could do their magic. The stock stuff was in good shape so I elected not to have any additional coatings done to the surfaces even though I really wanted to. Calving was to be setup for motocross for a 210 lb B class rider.
When the frame came back from powder coat it was time for assembly. I took my time and put things together and pulled them apart several times just to be sure of everything fitting correctly.
Now that the front was mounted it was time to work on the rear along with the subframe, air box, and carburetor. This is where things can get REALLY tight on this conversion. There are ways around if using different air boxes and intake boots, but I know it can work with the stock stuff with just the right amount of tweaking and twisting.
In the end, it all fit and have just enough clearance, even with the rear fully shock compressed there is no contact between the spring, carburetor, or intake boot. Perfect.
As stated in an earlier post, it was a tight squeeze with the stock air box and intake boot. If you look back a few posts, you can see the misalignment I had to deal with as well as the small space the carburetor had to fit into. After several tries and pulling things in and out, I was able to get a suitable setup. I still hadn’t picked up a gas tank, so that was next and I also needed to make sure the top of the carb would clear the gas tank for the throttle cable. notice the 45* angled throttle cable adapter for the carb top.
Radiators were next up. I went with Myler’s Radiators due to previous experience with them. They flat out work and are strong as hell. I used the KX250 radiators as they mounted up to the frame, obviously. The issue came in the area of the lower tanks hitting the head. I had to clearance (read punch holes with a die grinder and have my buddy weld them up) the tanks, and the cylinder. There is enough material on the cylinder to remove about 1/16” of material in the area where the contact was being made. This allowed the radiators to clear the cylinder (along with the mods to the radiator tanks) ever so slightly. I used a Myler’s Radiators silicone hose kit for the 250 and adapted it to work with the 500 hose routing.
The pipe and silencer were hand built by Growler Racing, the same guys that did the engine work. This pipe is a thing of beauty and has been on several KX500 builds, even some featured by MXA. They call it the Pit Viper and man is it pretty. Full cone pipe that is hand cut, and hand welded.
The silencer is also hand built by them and it sounds great. Both pieces mounted up flawlessly while using a few pieces from various bikes to make it fit perfectly.
Don’t mind the missing exhaust hangers, brackets, and puffs of smoke coming from the silencer to pipe connection. Those parts arrived shortly after this video and were installed before completion.
After getting the plastics installed and all of the heat cycles completed for break in, it was time to take the bike out for the maiden voyage. We have a short sandy track near the house that we frequently ride, so that’s where we headed. Here is a short video of some break in laps without beating on her too hard. Don’t mind the squid riding the bike
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