Upgrade to enjoy this feature!
Vital MX fantasy is free to play, but paid users have great benefits. Paid member benefits:
- View and download rider stats
- Pick trends
- Create a private league
- And more!
Only $10 for all 2024 SX, MX, and SMX series (regularly $30).
Once the bike got good and warm, I found that it pulled relatively well from mid to lower top. It definitely gets up to speed just doesn't have that explosive hit like my 2007 KX250 does. The 87 has a LOT less low end pull as well.
The bike felt relatively comfortable on track considering it's 34 years old. I have stiffer fork springs installed and the shock already had a heavier duty WP spring installed. I found I could jump and not bottom the suspension as I initially feared. The ergonomics felt very dated of course, like I am setting IN the motorcycle rather than ON it.
The brakes started working pretty good too after a couple motos (new pads front and back). A previous owner of this machine replaced the front brake line with a steel braided unit for better feel. The single piston caliper leaves a lot to be desired. I have a dual piston caliper from a later model KX125/250, but the mounting bolts look a lot different.
Bike ran pretty well all things considered. Someone was at the track with a drone, if I can track down their insta I think they got a little footage of the 87 on track.
Matika doesn't appear to offer hubs/baskets for the 87 KX250, though they do/did make a kit for the 88-91 KX250. Part numbers are not the same at Kawasaki.
What do folks do when there aren't new baskets available, but there are significant wear spots (fingers)? Feels wrong to file them down but maybe that's my only play...
The Shop
It looks like Mitaka doesn't offer a clutch hub tho, but the basket is worse for wear.
Got some good tips here: https://www.vitalmx.com/forums/Tech-Help-Race-Shop,42/1987-Kawasaki-KX2…
Should have the clutch basket this weekend.
RTFM
clutch spring bolts 78 in/lb
Main: 165
Pilot: 45
Also swapped the needle for a Suzuki NECH, which I'm told will help the bike run better. The needle with the 94 KX250 PWK38 is too rich for the 87.
The 87 throttle cable is a bit too short for a new throttle assembly I have, so I'm ordering one that is hopefully 20mm longer in length.
Circling back to this after a rough 2021/22, and moving to a new city. Sort of lost my place with this bike, it sat mothballed since last post.
I had taken the carb off in 21, and didn't note where I left off last. I decided to have another go at the new Sudco Keihin PWK 38 - I have a new motion pro throttle assembly and cable to go with it now.
So heres where I am as of today. I rode the bike around the yard and it feels anemic and lacking power. It bogs on heavy throttle from idle. Deets below.
Recapping, bike has a replated cylinder with overbored piston, fully cleaned powervalve system with fresh seals, Boyesen RAD valve, new pre-oiled air filter, stock pipe with a few minorish dents, stock muffler with fresh packing.
The carburetor is a brand new Sudco Keihin PWK38 Air Striker (long body).
Jetting:
pilot: 55
main: 170
clip: middle position
slide: unknown no markings
needle: unknown no markings
Premix is at a 32:1 ratio (Castrol 927, it's what I had on the shelf tonight).
It sounds lovely revving when parked. Lots of bark, and crisp. What I'd consider a normal amount of exhaust smoke out the muffler. When riding, the bike feels anemic with lackluster power in the mid/top end. I know it's an older steed but it just struggles to go. If I apply full throttle in second gear from a gently rolling pace, the bike bogs out. I can pull the clutch in and rev it up, but it def feels like it is either starving for fuel or is running rich. I'm not skilled enough jetting to know how to feel the difference.
This plug read is after about 10 minutes of riding, with some full throttle attempts. It was not a WFO chop fyi.
My question also has to do with float level. I'm reading conflicting reports on what angle the carb should be. The overflow tube is at a 45 degree angle (vs more of a 90 degree bend with a similar PWK on a KTM).
Looking for any tips or wisdom on dialing this carb in.
Pit Row
Another unrelated issue with this bike is that the front single piston brake is absolutely worthless.
It has a braided steel line with fresh fluid and properly bled. The lever feels tight, but the brake is literally useless. Four fingers barely slows it down.
The pad doesn't appear to be making good solid contact with the rotor.
Steps for removing the front brake pads:
1) Remove caliper using two 5mm allen socket bolts
2) Rotate pin so that the clip head is accessible with a pair of needle nose pliers
3) Remove clip
4) Pull caliper pin out with pliers
5) Remove pads and inspect
The residue on the disk was caused from a leaking caliper seal. I was lucky to find a rebuild kit for such an odd-year bike. The same caliper was shared by the KX125/250/500 as well as the 87-88 KLR650.
Will report back once I have the kit and a little time to rebuild.
https://www.ebay.com/itm/115829117161
Regarding your jetting, I had a similar issue with a recent restoration, sounded great on the stand, garbled under load. I thought it was my jetting, too. I got directed to check my coil and that was the culprit. You might get yours checked or replaced.
Just in case mine tests bad, are the cheaper replacement coils shown on ebay worth the effort?
Yea man, no telling how long mine lasts but it was like $15 shipped, so I was like, f*ckit. Bolted it on 4 days later and my bike ripped. My jetting was spot on and I really didnt want to pull the carb and airbox out again.
When I read your post it sounded eerily similar to what i was dealing with
https://www.vitalmx.com/forums/moto-related/2-stroke-jetting-help
I don't have specs to test my coil. Had to order another manual since I lost mine in the move. But I went ahead and ordered one of those $10 coils to have on hand just in case.
When this bike was running in 2021, it had a similar issue - weak power on bottom then garbled and fell on itself up top. Very similar indeedy!
EBay coils work just fine and it’s great to have a spare around.
Great build!
Tips for getting these Phillips screws out?
I have an impact driver, but am a little bit worried about breaking the magnesium hub
Pulled the rotor off, cleaned it up real good, bolted it back on with loctite
Post a reply to: 1987 Kawasaki KX250 low-key restore