1987 Kawasaki KX250 low-key restore

2/28/2021 7:56pm Edited Date/Time 2/28/2021 7:57pm
Took the '87 KX250 out to Scrubin' Dirt today. Got it warmed up and took on the track for the first time since I've owned /rebuilt it (and probably first time it's seen a mx track in at least a couple decades).

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.
4
2/28/2021 7:58pm
mpeters wrote:
Watched your story with amazement. Many would not have done that. Was curious about the end game. Now what? It's not ride it's the rider. Nice...
Watched your story with amazement. Many would not have done that. Was curious about the end game. Now what? It's not ride it's the rider. Nice job
haha, probably not the smartest choice for a Rescue for sure. Plan is to race it once, then sell to someone to do the cosmetics or not - gotta clean out the garage a bit after this.
mpeters
Posts
21
Joined
2/27/2021
Location
Eastlake, OH US
2/28/2021 8:14pm
My friends and I were talking today about these builds as i was tearing my engine down. Most said you all are looking to sell to a high priced collector/nostalgic. I am trying to keep my build to $2500.00 which is what by far most people would pay. I am going to try to document pricing. Nobody goes into cost on these builds vs true life worth. That cr250 gotta have 8-10 grand on a bike worth really 4 grand. Like putting 50 grand into a 73 Chrysler.
2
3/1/2021 8:23am
Just ordered new set of clutch plates, and a cheap set of used RM85 footpegs, which I hear may bolt right on to the 87 KX250 frame with no modifications.

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

Matt Fisher
Posts
3947
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4/1/2008
Location
Visalia, CA US
Fantasy
1084th
3/2/2021 10:04pm
Just ordered new set of clutch plates, and a cheap set of used RM85 footpegs, which I hear may bolt right on to the 87 KX250...
Just ordered new set of clutch plates, and a cheap set of used RM85 footpegs, which I hear may bolt right on to the 87 KX250 frame with no modifications.

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...
1
3/3/2021 4:11am Edited Date/Time 3/3/2021 4:14am
Just ordered new set of clutch plates, and a cheap set of used RM85 footpegs, which I hear may bolt right on to the 87 KX250...
Just ordered new set of clutch plates, and a cheap set of used RM85 footpegs, which I hear may bolt right on to the 87 KX250 frame with no modifications.

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...
Well dang, the part numbers aren't the same from OEM. But this is good.

It looks like Mitaka doesn't offer a clutch hub tho, but the basket is worse for wear.
3/10/2021 9:43am
The pressure plate and hub actually look/feel relatively good. The basket splines are badly grooved.




3/11/2021 7:36am
Found what appears to be one of the very few remaining Mitaka clutch baskets for the 1987 KX250. Went ahead and ordered, it'll be a few weeks for shipment from the UK.


1
yak651
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Appleton, WI US
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3/11/2021 7:54am
The pressure plate and hub actually look/feel relatively good. The basket splines are badly grooved. [img]https://p.vitalmx.com/photos/forums/2021/03/10/482368/s1200_158461852_10158299950869067_3612273313117832435_n.jpg[/img] [img]https://p.vitalmx.com/photos/forums/2021/03/10/482367/s1200_158609904_10158299950689067_8216980414521285482_n.jpg[/img]
The pressure plate and hub actually look/feel relatively good. The basket splines are badly grooved.




Would think a machine shop could repair that by welding and then machining down?
3/11/2021 7:36pm
Maybe, though I'm reading that the manufacturers used trash Al for casting these parts, and that they are difficult weld cleanly.

Micahdogg
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Location
US
3/18/2021 1:31pm
I know its frowned upon, but I've had good luck filing that stuff away from the basket.
4/5/2021 10:38am
Got the jet block gasket replaced last weekend, also confirmed jetting:

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.
1
12/3/2023 4:11pm

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. 

 

12/3/2023 4:13pm

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.

kx250

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. 

s3.jpg?VersionId=.g8

s1 0.jpg?VersionId=T9kOYz9dbyI5BT

s2 0

 

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). 

floatlevel-45degree

floatlevel-90degree

 

Looking for any tips or wisdom on dialing this carb in. 

1
12/3/2023 4:26pm

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. 

front-brake1

 

disk.jpg?VersionId=mmt7EX7zB.DIDW8. TgmY5V1

 

12/3/2023 5:03pm

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

pinclipjustvisible.jpg?VersionId=sra77IJtz

3) Remove clip

removepinwithneedlenose

 

4) Pull caliper pin out with pliers

pullpinout

5) Remove pads and inspect

caliper3

 

12/3/2023 5:07pm

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

s-l960

bonseff
Posts
1255
Joined
3/29/2011
Location
Frisco, TX US
12/3/2023 5:56pm

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.

1
12/3/2023 7:00pm
bonseff wrote:
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...

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? 

bonseff
Posts
1255
Joined
3/29/2011
Location
Frisco, TX US
12/3/2023 7:12pm

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.

1
12/3/2023 7:34pm

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! 

BoxcarWilly
Posts
148
Joined
10/5/2023
Location
Thunder Bay, ON CA
Fantasy
3901st
12/4/2023 1:42pm

EBay coils work just fine and it’s great to have a spare around. 
 

Great build!

12/5/2023 6:09pm

Tips for getting these Phillips screws out?

I have an impact driver, but am a little bit worried about breaking the magnesium hub

20231205 210531

12/7/2023 7:19am

Pulled the rotor off, cleaned it up real good, bolted it back on with loctite

20231206 204120

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