1992 Yamaha yz250

Jay92
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17
Joined
3/9/2021
Location
FI
Edited Date/Time 11/19/2021 5:09pm
Owned the bike since 2003-4, rebuilt the engine with all new bearings, seals, piston, rode a bit here and there until 2010, then bike sat in the garage for 10 years.

Starting point, February 2021
Fresh gas, started on the 5th kick or so Smile


Idea was to do a full restoration in original colors but.. it went to a bit different route.

Stay tuned, updating shortly.
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Jay92
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17
Joined
3/9/2021
Location
FI
8/15/2021 1:07am
No major damage but old and crusty.
Rim was cracked, pipe had nice dents, surface rust here and there.






2
38special
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545
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6/30/2010
Location
US
8/15/2021 6:36am
One of my favorite bikes of all-time. Will be watching your progress.
1
Jay92
Posts
17
Joined
3/9/2021
Location
FI
8/15/2021 9:04am
Frame prepped for blasting/paint.

Frame and pipe blasted, pipe dents fixed.. cleaned up nicely.. all the big dents came out so pretty happy with the result.
1

The Shop

Jay92
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17
Joined
3/9/2021
Location
FI
8/15/2021 9:52am Edited Date/Time 8/17/2021 10:45pm
Poor lighting but the frame was wet painted, I wanted the original color and also to be able to see cracks as the bike will be ridden.

I tried to track down the original code for the paint but no luck. ”Purplish white solid 1” and its abreviations were the only thing to go by but the details/formula for the paint were missing and Yamaha could not help with the details.

”Yam 912” name could be found from one paint chart but PWS1 was apparently used for later models of other Yamahas thru out the years but with varying ”tint” apparently. Eventually the painter found a Toyota paint that, according to him, had the ”correct formula”.. I think it turned out great and the price of 150€ was a steal.

3
Jay92
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Location
FI
8/16/2021 11:27am Edited Date/Time 8/17/2021 10:46pm
All swingarm and linkage bearings/seals were removed. Old ones were pretty rusty. All bearing surfaces were protected and the swing arm was blasted as well.



Rear rim was welded and rims were painted

1
Jay92
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3/9/2021
Location
FI
8/16/2021 11:34am Edited Date/Time 8/17/2021 10:47pm
Pipe welds were blued, was thinking about painting but I liked the raw look. Clutch, power valve and water pump covers were painted.


3
Jay92
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3/9/2021
Location
FI
8/16/2021 11:55am Edited Date/Time 8/17/2021 10:47pm
Radiators were a bit tacoed but they will have to do for now, cleaned and painted.




New hose kit with a bit of color.
Wiring was cleaned, it was in pretty good shape.


Painted the front brake master cylinder, throttle housing etc. small bits and pieces. New throttle cable and some NOS spare parts like brake lever cover, throttle housing screws and top cover from cmsnl.com

2
FarleyMX25
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218
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10/2/2017
Location
Harrison, TN US
8/16/2021 12:01pm
Did you do the painting on all the parts? Is there any 2k clear coat on them?
Chance1216
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6119
Joined
4/1/2018
Location
Carson, CA US
8/16/2021 7:28pm
Jay92 wrote:
Radiators were a bit tacoed but they will have to do for now, cleaned and painted. [img]https://p.vitalmx.com/photos/forums/2021/08/16/505933/s1200_0C4E82F7_AF79_4D9C_9693_7096C6C35085.jpg[/img] New hose kit with a bit of color. Wiring...
Radiators were a bit tacoed but they will have to do for now, cleaned and painted.




New hose kit with a bit of color.
Wiring was cleaned, it was in pretty good shape.


Painted the front brake master cylinder, throttle housing etc. small bits and pieces. New throttle cable and some NOS spare parts like brake lever cover, throttle housing screws and top cover from cmsnl.com

There’s a few videos on YouTube that have helped me with bent radiators. I believe it was Cameron Niemela who had one for straightening them tacos out.
1
buenavides
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34
Joined
4/9/2019
Location
Orlando, FL US
8/16/2021 7:42pm
Good luck with this build, keep us posted with more photos.
1
TooOld4WFO
Posts
628
Joined
4/1/2018
Location
Fresno, CA US
Fantasy
565th
8/17/2021 10:59am Edited Date/Time 8/17/2021 11:00am
Great job. I need to restore a 91 WR 250 so I am interested in this build.
Hopefully you haven’t had any issue sourcing parts. That would be very encouraging.

How were these early 90 motors? I’m thinking pretty tractable with loads of low end.
1
Jay92
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17
Joined
3/9/2021
Location
FI
8/17/2021 11:52am Edited Date/Time 8/17/2021 10:43pm
FarleyMX25 wrote:
Did you do the painting on all the parts? Is there any 2k clear coat on them?
Frame was done by a pro but all other parts and wheels were done by me.

Wheels were painted with a can and have several clear coats, will see how they hold up. Brake cylinder has glossy black, several coats but no clear coat as they looked quite glossy enough without it.

Radiators (and some other bits) plus clutch/power valve cover were painted with a heat resistant matte paint (silver and black), these should harden when heated but have no separate clear coat.

Jay92
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17
Joined
3/9/2021
Location
FI
8/17/2021 12:17pm
TooOld4WFO wrote:
Great job. I need to restore a 91 WR 250 so I am interested in this build. Hopefully you haven’t had any issue sourcing parts. That...
Great job. I need to restore a 91 WR 250 so I am interested in this build.
Hopefully you haven’t had any issue sourcing parts. That would be very encouraging.

How were these early 90 motors? I’m thinking pretty tractable with loads of low end.
Thanks!
Early 90´s Yamahas have low/mid power with the stock pipe, new FMF and PC pipes are readily available and can change the character quite a bit. For slow hobbyist like myself, its easy power to ride.. someone faster would want to put a PC pipe to make it rev longer with more top end power.

Cmsnl is the premium source for NOS parts, in general, things that are wear items / smaller parts are available, larger parts like cylinder, cases, tanks, air boxes are harder to source. Suspension parts are available and can be serviced easily. Pistons, cranks etc as well. You should be fine with a WR as most YZ stuff will fit, -91 is a bit of an odd year so parts are a bit harder to find.

Heres a list of sites that have a selection of parts, sometimes for unicorns as well.
I have bought from some of these.

Vintage parts
https://www.cmsnl.com/
https://www.enduroklassiker.at/
https://www.v1mx.nl/
http://www.vmx-service.eu/
https://www.jkracinguk.com/

Graphics
https://www.evo-mx.com/

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TooOld4WFO
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8/17/2021 4:29pm
That kind of help with the links is outstanding Jay.
Thank you for that.

I would have preferred the stock pipe but this one has a Bills.

You did a great job with the rattle cans.

This YZ will look fantastic brother. Great thread.
3
MX252
Posts
44
Joined
12/12/2020
Location
WA US
8/17/2021 8:24pm
Nice choice! I had one brand new early 92 raced it for two seasons loved that bike!, one of many one of my favorites we had great colors back in the day and so was our gear, keep the pictures coming looking forward to seeing the finished product.
2
Jay92
Posts
17
Joined
3/9/2021
Location
FI
8/19/2021 11:14am Edited Date/Time 8/19/2021 11:18am
Here are some added, not original parts.
Modern larger foot pegs from https://www.vandijckmx.nl/
They also have oversized pin sets (I bought new originals as there was no play)

Polished the original brake lever


New HEL brake lines. Caliper was cleaned and new pads, pins etc

HEL line in the front as well, new Renthal bar, cant remember the bend but this was new on -06 yz if I remember correctly

1
Jay92
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17
Joined
3/9/2021
Location
FI
8/20/2021 12:26am Edited Date/Time 8/20/2021 12:53am

As I wrote earlier, this is going to be a bit different, some new parts, some original, some traditional color schemes from the past (more on that later) but not a 100% copy.. it will be a combination.



Shock has new bearings and was serviced, new bump stop. Painted the spring, several coats and clear on top as well. Will see how it holds up.


Wanted to do a carbon silencer (a hint of the color scheme), contacted Arrow but no measurements remained of the old stuff. Will need to do a custom silencer.

As an experiment I painted the silencer with matte heat resistant paint, should harden when heated but might not last. Bike has been run with spikes and silencer has taken hits so the silencer is something I will most likely need to redo at some point.. carbon sleeve most likely, will see.

As a side note, hubs and spokes where cleaned up with steam, wd40 etc but not painted at this stage.
Most likely I will ride the bike and see if the rim weld and paint holds up, excel rims are available so those might be on the list in the future. I cleaned the wheel bearings, new grease and seals to the front.




Swing arm was blasted, bigger marks where removed and the swing arm was cleaned up. Wanted a dull finish so no polishing or paint, just wd40 and abrasive pad. If something was used a lot in the project it was wd40 and 1500 grit abrasive pad, all alu parts and small parts like nuts and bolts really cleaned up well with this combo.

This is sort of the worst of the worst that you can see close up, these will be dealt with later.

3
Jay92
Posts
17
Joined
3/9/2021
Location
FI
8/25/2021 11:43am
Added disc and fork guard, UFO plastics.

Looks like 2 bolts, 2 minutes and done but it was not Smile Needed to change the brake caliper bolt to a longer one (35 to 50mm), created threads inside the front axle (8M) and bought 2 x 7mm wide rubber grommets for the bolts so that the disc guard would sit correctly.

Fork guards needed a bit of cleaning up with a knife, not exactly perfectly molded out of the box but no issue on visible parts





2
Jay92
Posts
17
Joined
3/9/2021
Location
FI
10/4/2021 3:42am
So I finally got the bike to a semi-finished state. Still debating if I should go for all the decals/stickers. Its a version after all with the white frame, silver engine parts/covers, red spring, modern foot pegs.. so not a spitting image of the 1992 factory bike (the -93 would have been closer to factory -92).




11
sende
Posts
2376
Joined
1/15/2013
Location
FI
Fantasy
4967th
10/4/2021 4:22am
That looks do good!! Love the Chesterfield look.
TooOld4WFO
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Fresno, CA US
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10/4/2021 2:55pm
Outstanding job Jay and great images.
The Chesterfield look is so clean and well done. I struggled with turning the WR into one in that series.
For me it’s a struggle to finally post done images. Hard to let go of that process.
That bike needs nothing. Beautiful.
1
TooOld4WFO
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Fresno, CA US
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11/18/2021 5:14pm
Jay, some questions.

I’m finally digging into the 1991 WR 250.

Rear shock. I measured my rear shock spring off the shock and came up with 10 1/4” in length. I noticed that there was at least 80% or more of the pre-load on the assembled shock. Is this normal? I was thinking the spring was worn out but the motor suggests otherwise. Still on original piston.



Front disc. I shot some images of my front disc. Not sure if this is how they are or if warped. If warped it appears to be somewhat concentric in how much. I took some images of this.






Thanking you in advance for any and all assistance.
sandman768
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6583
Joined
3/21/2014
Location
Saratoga Springs, NY US
11/19/2021 9:30am
That rotor looks to have a chunk missing around 4 o’clock … and no, should be flat, here are my old & new rotors from my 92 build
1
450exc115
Posts
678
Joined
11/6/2014
Location
Hebron, CT US
11/19/2021 10:14am
I have had 2 of 3 front disks on my late 80 Yamahas Spring like yours when removed from the hub. Just toss it and replace it.

Back in the 80s and even 90s the OEMs used more damping and less spring rate when designing suspension so compared it to todays bikes I'm not surprised to see a bunch of preload on the spring for a rider to get the sag in the box.
1
Jay92
Posts
17
Joined
3/9/2021
Location
FI
11/19/2021 10:55am
TooOld4WFO wrote:
Jay, some questions. I’m finally digging into the 1991 WR 250. Rear shock. I measured my rear shock spring off the shock and came up with...
Jay, some questions.

I’m finally digging into the 1991 WR 250.

Rear shock. I measured my rear shock spring off the shock and came up with 10 1/4” in length. I noticed that there was at least 80% or more of the pre-load on the assembled shock. Is this normal? I was thinking the spring was worn out but the motor suggests otherwise. Still on original piston.



Front disc. I shot some images of my front disc. Not sure if this is how they are or if warped. If warped it appears to be somewhat concentric in how much. I took some images of this.






Thanking you in advance for any and all assistance.
Good to see you working on the bike.
Sandman and 450exc pretty much nailed it.
Shock preload looks like its about the default, so normal for the era, measure/adjust preload before installing (forgot myself, extra work on the bike) .. and your dics is toast.
TooOld4WFO
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11/19/2021 1:27pm
Thanks guys for the responses.
The missing section had a magnet secured in that area. So the front wheel revolutions were being collected. I assumed it had a odometer on it at one time.

I am now more concerned with the hub being slightly different from a 92.
TooOld4WFO
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11/19/2021 5:09pm
Looks like I will keep this thread going with my questions… Apologies..

It appears there is 2 different length spokes for the rear hub?

92 YZ 250 spokes do not work on the front.

Worked a deal with a eBay seller of a disc off a wheel.

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