CSAR FE's 91 KX500 Build

Id say that's a score. Enjoy that monster. Keep us updated on the build!

Smoken deal....

not bad for the price at all.... my advice is to stockpile parts, many are drying up.

I figured as much, given how old it is. It really only needs a few small things as far as I can tell, like fork seals, brake pads/rotors, gas cap seal, etc. I’m sure I’ll find more as I dig into it though. It runs great. Most everything else will be cosmetic. I’m not a fan of Warp 9s after smashing a set a few years ago, so the stockers will probably get rebuilt. I have a spare 18” A60 hoop lying around. Just need a front and they’ll go out to Faster USA.

The Dig will pretty much be flat after that beast blows all the sand off the top!!

Worked on swapping out the old factory radiators with the chinese fleabay ones I got with the bike. I expected it would be the case, and sure as the sky is blue, the fitment was shit. The hose kit is generic as well. So I spent close to two hours working to get these fitted on. After a lot of dremel work, bending of hose barbs, and cutting of hoses, I got them on. Hopefully they work, everything holds and the bike doesn't overheat. If they don't leak and the radiator shrouds line up, it'll be better than the JB welded stockers. I will probably buy a set from Myler's eventually, since you can't get new factory rads anymore.

I'm working on the cleaning part, so don't jump my case just yet. Powdercoating will probably be the last thing I do once I get everything else squared away. Seat cover is on the way from Guts. Ordered a new rear fender and I'll be putting a new IMS translucent tank on as well. The tank that came on it is a really weird shade of green and looks like shit. I'll be working on stripping the paint off of the swingarm and the subframe tomorrow. I'll be going with the brushed aluminum look. The pipe will get rust-busted as well. I have a spare 40mm Keihin PWK short body with STIC lying around that I am going to try and fit. It is a short body, but I think it may work since the reed cage has a spacer installed that is probably 4 or 5mm wide, if I had to make a guess.

Looks awesome, like some have already posted some parts like cases, gears, power valve gear is pretty hard to find now... They are awesome bikes though...

Here’s mine...

Rust busted the pipe today, and blued the welds. I also stripped the paint off the subframe and gave it the brushed aluminum look. Started working on tidying up the air box. Should have that finished tomorrow. I should also have the swing arm off and finished up tomorrow as well. I had a spare 40mm PWK with STIC lying around, so I installed that with an extra throttle and cable assembly I had lying around from my TX300. Much smoother. Hopefully it all mates together properly when I get the air box back on.

Swingarm done.

You may have to modify the carb cap so it doesn't dig into the inside of the left tank saddle. If you install your tank, you'll see what I mean.

Everything else should line up fine with the airbox.....I have the same setup - airstriker, rad valve, reed spacer.


What needle do you plan on using?

quicken wrote:

You may have to modify the carb cap so it doesn't dig into the inside of the left tank saddle. If you install your tank, you'll see what I mean.

Everything else should line up fine with the airbox.....I have the same setup - airstriker, rad valve, reed spacer.


What needle do you plan on using?

Great tip, I just checked it and mine was definitely rubbing on the tank. Did you just file the carb cap down a bit?

I’m just running the needle that came in the bike. I need to check and see what it is, but I think it’s a JD needle. Any needle suggestions? The bike had a 45 pilot and a 155 main, which seems a bit off to me. I’m sure these bikes jet a little differently though, with the stronger signal.

Can you please explain the process and products used on your swing arm? That turned out fucking awesome I want to do the same to my K5

CSAR FE wrote:

Great tip, I just checked it and mine was definitely rubbing on the tank. Did you just file the carb cap down a bit?

I’m just running the needle that came in the bike. I need to check and see what it is, but I think it’s a JD needle. Any needle suggestions? The bike had a 45 pilot and a 155 main, which seems a bit off to me. I’m sure these bikes jet a little differently though, with the stronger signal.

It'll take a little more than filing it.

I cut off the area below the welch plug (yours looks to be cast in) and tapered it back to almost inline with the throttle cable (pie shaped wedge). Just stay above the o-ring to keep the integrity of the edge of the cap. Either weld in a little piece of aluminum to close off the hole, or do as I did and fill it with JB Weld. Finish off the edges and paint it with flat aluminum paint and it's hard to tell it's been modified. Since the tps is gutted out of the carb, it's unused space.



I don't have any solid jetting specs ( my 500 is a project bike like yours). I mainly messed with the jetting when I got it, but was never satisfied with the results. I haven't been on a bike in over a year (life happens) but hope to resume with it this fall.

What I remember...

8 slide
tried various RM and YZ 250 needles that I had (probably need a needle with a larger straight section)
down to 38-40 pilot ( and felt like I could go lower)
Main jet around 160 I believe

Like you mentioned, the signal is so strong with this carb (especially a 38) that jetting may be a little "out of the box".


BTW, I picked up a metering block from George at his shop last year (nice guy...lives nearby) so I'm definitely interested in your stic thread and any jetting info that you have. Plan to use it on this bike, but want to get the basics nailed down before I throw another variable in the equation.

RABnasty wrote:

Can you please explain the process and products used on your swing arm? That turned out fucking awesome I want to do the same to my K5

Got some paint stripper from Home Depot (the heavy duty gel stuff) and used that, along with a wire brush, to strip the paint off. After that, 220 grit sanding block to get the brushed aluminum look, then cleaned it with aluminum wheel cleaner.

Thank you!

Spent the last few days cleaning up the frame and engine. Got a bunch of parts in yesterday, so I spent today replacing all the chassis bearings. Some were ok, but most were trashed or rusted out. Everything feels much smoother and tighter now. Put the correct shock spring on for my weight as well.

The left fork seal was leaking, so I replaced them on both, along with the bushings. The oil was filthy. I don't think anyone has touched the forks in years. I think someone got some water in the right fork, as the piston had rusty-grunge on it, so I had to pull the piston and shim stack apart to clean it up. Someone put those shitty motion pro fork bleeders on them, so my guess is that's how the system got contaminated. I'll be getting the normal screws and throwing the others in the garbage where they belong.

I took the PWK short body off as I didn't want to do all the work quicken discussed to make it not rub a hole in the tank. I'll just buy a 92M STIC for the screw top from George in the future. I installed a 55 pilot, 168 main, and the N82P needle on clip 2. Its a little rich, but it still ran much better than before.

Got some shroud graphics off of eBay as placeholders until I can get RevDesigns to make me some custom ones. These shroud graphics are the shittiest things I've ever seen (but what can you expect from eBay?). Installed an 18 front fender and number plate. I had to make a little 90 degree bracket to make it work. Looks great. Guts seat cover installed, although the foam will need to be replaced at some point as its worn out and a little lumpy in some spots.

New chain guide and bar clamps coming from BRP next week. I'll be doing the weld-on Scott's damper at some point. New OEM clutch plates and frictions are coming in next week as well, along with a Pro X billet clutch basket (since you can't get a Hinson for it anymore).

Forgive the filthy garage. I've been jobbing on this thing for a week straight.

Received some more parts in today. New OEM clutch plates and frictions, along with some other goods. This Pro X basket is a nice piece, and I don’t feel near as bad about not being able to get a Hinson after handling this one. The clutch should be nice and smooth after install. It feels notchy right now. The basket is probably as old as the bike is.



BRP sent me the wrong chain guide, so I’ll have to send that back for exchange.



Forks are at the local shop as they make a strange clunking noise at full extension. I thought the springs were a touch too short (negative preload), but the shop owner though the rebound felt way too fast and there could be a problem with the valve on top of the piston rod.

New basket and plates are in. I had to drill out the rivets on the stock piece to get the primary drive gear and backing plate off to be installed on the Pro X basket, along with new rubber dampers. The idler gear had to be pressed out of the stock basket and pressed into the Pro-X basket as well. The stock one was notched out really bad, enough to feel in the clutch lever. The freshened up clutch should feel great, along with a new OEM clutch cable routed in the “Team Green” manner. The clutch cover gasket fell apart (probably the original one), so I’m waiting on a new one to get it back together.

I'm going about this build a little backwards, because I'm moving to another state in about a month, so I'm taking care of stuff that doesn't require me to strip the bike down completely. Once I move and get settled in, the motor is coming out and going to Tom Morgan, and the frame will get powder coated.

Since the last time I've posted, I cleaned up the stock hubs and rebuilt them with Excel A60s, Excel spokes, new bearings/seals, and Tusk brake rotors. They came out really well for my first set, I think. Threw on a fresh set of Nitromousses and Michelin Starcross 5 Meds.

I decided to get a new pipe since the one that came on it was bent in pretty bad. I went with a Pro Circuit Platinum 2. Threw on a Boyesen Ignition cover for fun, and some WC frame guards. The Chinese rads were giving me OCD fits knowing how badly they fit, so I bought a set from Myler's and installed them. They are very well made, and they fit as good as the OEM ones did. I also rebuilt the shock. New graphics in from Rev Designs.

Next on the list is new seat foam. The old stuff is roached, which makes the seat cover look lumpy in some spots. I'm also not digging the green cover, so I have a new black one coming from Motoseat. New Scott's Damper and weld-on tower is inbound.

Scott's Damper and weld-on tower kit came in today. As a general rule of thumb, I won't rip around the dez without a damper. They have kept me out of the hospital more times than I can count.

It took me all day, grinding the tower to fit, and getting the post height just right. I'm not a pro welder, just a dude with a little spark box in his garage, so don't judge too hard! Overall, I am happy with how things turned out. Everything works perfectly, and will be looking good once I get the powdercoating done.

I don't know about anyone else, but I'm a fan of how certain hand guards make a bike look. Of course, not catching cactus and rocks in the knuckles in a minor side benefit.

Nice!!!!!!!

Treat those Riv Nuts on the subframe gently. They are weak as hell and are a total pain when they start to spin.
On the clutch cover... the brake pedal was famous for punching a hole in the clutch cover in a crash. I used to take a
piece of aluminum, shape it and JB weld it to the case to act as a guard by spreading out the impact. Worked great!!

Also, the chain is famous for sawing through the sub frame. All sorts of guards and home remedies were tried but the one I tried that worked the best was screwing a piece of plastic (about 1" tall and 4" long) into the chain slider on the swingarm. Looked like it would be flimsy as hell but totally worked great.

A Honda CBR 600 F2 front brake caliper can be made to fit on the rear of the KX500 and WAY better than the stock unit. Works killer.

There is a way to adapt a later year rear fender to this bike if you don't dig the scoopy rear fender.

Ignition coil mounting tabs would crack often. Keep an eye on them.

Have a blast on it!!!

Installed new seat foam and a black seat cover from Motoseat. Received a STIC metering block from George today and installed it after work. Upped the pilot by two sizes, and the main by 5. Fired right up, didn't smoke at all (unlike before), and is way more responsive and crisp sounding on the stand. Excited to see how it feels in the dez.

Great work dude, love these things! Been looking for a 500 for myself as a project bike but having the same problems as you...massively overpriced or absolute junk!

deccr250 wrote:

Great work dude, love these things! Been looking for a 500 for myself as a project bike but having the same problems as you...massively overpriced or absolute junk!

Cheers man, good luck on your search. This one looked like a hunk of shit, but everything important was straight, which made for a good base for this build.

Received an ARC clutch perch lever setup, brake lever and rotating bar clamp for the brake side. These things are butter smooth. The clutch action feels great on this bike. When I first got it, it was really stiff, and you could feel the notches in the basket through the entire range of the clutch pull. I also rebuilt the front brake master cylinder. Feels much better. All I need for the front end now is a new brake line.

Got the driveline installed. The original gearing was 14/47. I'm a huge fan of Dirt Tricks sprockets. They don't make a front sprocket for the 500, and the smallest rear they make is a 48. I ended up getting a 15T Renthal front and a 48T Dirt Tricks, with a DID Narrow X-Ring chain. I think this gearing will work well, especially with the STIC, and should be good for 100+ mph on fire roads. This is pretty much a bulletproof driveline. I had to trim the case guard back about 1/4" to make room for the larger C/S sprocket.

When I replaced all the chain rollers with All Balls rollers, I didn't realize that they are generic. The lower roller diameter is too big and pinches the chain, so I had to order a TMD roller that is made specifically for the 500.

Next up should be a Lightspeed carbon fiber front disc guard, Devol Skid Plate and Rad Guards, and a set of Rental KTM High Fatbars (my favorite bend).