1992 YZ250 back to life

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1/22/2016 8:14 AM
Edited Date/Time: 3/8/2018 2:18 PM

Everyone loves pictures...so here is the journey I've been on since about last October. Someone ran straight gas through the bike and seized it. The owner paid for the cylinder to be replated and bought a Namura piston for it before giving up. I've tried to be very economical and reuse whatever I can along the way. It is getting close!

EDIT - Photobucket bombed out this thread, so I moved all the pictures and revived this thread. Enjoy!

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Fixing the seat foam with silicone
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Seat cover from EVO
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Sanding and refinishing plastic. Most of the dark lines are razor cuts from a prior owner trimming the graphics. Also the fork guards were murdered out in blue krylon:
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Tearing it down
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Rebuilding suspension
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Frame and spring powdercoated, new front tire
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And we got a roller! New back tire, new steel sprocket, stripped swingarm. Linkage bearings were reusable!
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Getting into the engine. The big end rod bearing came apart and messed up the head. I removed 80% of the rash.
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Back in its home!!!
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Carb cleaning. I modded the body with a rivet to help hold the guts in place (the factory peening was weak)
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Plastic going back on. I reused everything except the left side shroud which was cracked
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Cleaning the silencer and polished the pipe. It has a couple dents, nothing major.
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Removing sold old anodizing and sanding out rash
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All done, with EVO graphics!
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1/22/2016 9:47 AM

Very nice work!!

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1/22/2016 9:56 AM

Most of my posts are about old YZ's, and here's another one...

AWESOME JOB!

If you live anywhere near Michigan, I will pay you good money to let me race that bike just one time. That is my favorite bike of all time and I'd love to throw a leg over it again.

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1/22/2016 10:53 AM

Well done! I always try to be economical during my builds but, rarely works out!

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1/22/2016 10:57 AM

I'm doing the exact same project! Frames currently being prepped etc! I'll start a report soon and follow this one!

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1/22/2016 11:16 AM
Edited Date/Time: 1/22/2016 11:17 AM

Very impressed by your work on the plastics and nice that you're going stock look, the 92s looked great!

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1/22/2016 11:53 AM

Thanks all! It feels good to see it all finally coming together (and to have less misc parts scattered around)

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1/22/2016 1:12 PM

Just returning the complement you paid my 89 kx 125, that's a nice restoration. I love seeing old bikes rescued.

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1/22/2016 2:53 PM

Good work man!

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“Scrub as hard as you want. It’s a two-stroke, it’ll come back” - Robby Marshall

1/22/2016 3:44 PM

Very nice work! I'm just starting on a 1990 YZ250 myself. I hope it turns out looking as nice as this build is going!

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1/23/2016 1:20 AM

Wich product did you use to make shinning plastic?

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1/23/2016 1:32 AM

Great work!

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He not busy being born is busy dying.

1/23/2016 6:56 AM

Steph500 wrote:

Wich product did you use to make shinning plastic?

Elbow grease! For real. Ive tried a few different plastic renewing products and am not certain if any work better than the others. But if you put in the sanding work it will start to shine on its own. Thats the hard part. You can spend 4 hours wet sanding a number plate and 5 minutes polishing it.

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1/23/2016 12:53 PM

Wow, that's a beaut!

That's some serious work you've put into the plastic, been there before and man, how satisfying is it bringing old plastic back to showroom condition?

The motor looks super clean as well, looking forward to seeing this finished.

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1/23/2016 11:14 PM

Nice work!

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1/25/2016 3:11 PM

What finishing polish do you suggest using? I'm happy with a 92 RM tank I restored but seeing your work I'm motivated to touch it up a little.

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1/26/2016 7:31 AM

I don't think the polish matters....like I said, i've used a few different ones...one is a McGuires headlight polish and what I've found is the sanding is what gets you the results. And the sanding is just an art that you have to learn by spending a ton of time. I can say that I finish up to 2000 grit and I've frequently had to go back and redo some parts. I usually wet sand, but sometimes have to dry sand because the water makes it hard to see what you are doing.

I've got about 40 hours in that YZ gas tank. Mostly because the prior owner trimmed up all the gas tank graphics with a razor blade!!!!!!!

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1/31/2016 4:55 PM

Did you have any issues rebuilding the seal head ? Mainly getting out the flat washer underneath the bumper to get to the seal ?

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1/31/2016 9:21 PM

No. I just used a flatblade screw driver to work the peening back carefully. I went around the seal head maybe 3 times to roll it back real nice and even. I do recall the washer being a smidge tight going in and out but nothing major.

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2/1/2016 2:05 AM

Thanks for the info, working a 89 YZ250, I've rebuilt seal heads before on 81/82 CR's but the flat washer is held in by a cir-clip. I was just a little worried about bending the peening. I can't believe nobody makes a seal head for these bikes. Thanks again

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2/1/2016 6:48 AM
Edited Date/Time: 2/1/2016 6:50 AM

No problem. I carefully went around the seal head with a ball peen hammer to roll the peening back over and it didn't feel super strong. Its fine as is, but I just wondered how many times you could realistically rebuild that thing. Maybe a couple more before the peening gets too weak? Good luck.

Edit - and to peel the peening back I found a decent sized socket that fit inside where the bumper was. Then I had a small gap to place my flat blade screw driver and start walking around the socket, flaring the peening out a little at a time. Just made a few passes like you are using a can opener. I think you could have just as good of luck smacking the side of the socket.

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2/1/2016 11:46 AM

holy crap, damn fine work, sweet bike!

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2/1/2016 12:03 PM

evomx244 wrote:

Thanks for the info, working a 89 YZ250, I've rebuilt seal heads before on 81/82 CR's but the flat washer is held in by a ...more

Technical touch (the KYB people) in Upland CA. have seal heads in stock for a 92 YZ250, I literally bought one last week from them.

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2/1/2016 2:40 PM

Hey VMX, is it stock style sealhead or a newer kind with circlip? I also wondered about bladders since the part number seemed to be a deadzone on that year. I was going to measure mine and get with technical touch, but it looked like it was in good shape still so I reused it.

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2/1/2016 3:56 PM

evomx244 wrote:

Thanks for the info, working a 89 YZ250, I've rebuilt seal heads before on 81/82 CR's but the flat washer is held in by a ...more

vmx3 wrote:

Technical touch (the KYB people) in Upland CA. have seal heads in stock for a 92 YZ250, I literally bought one last week from ...more

Leave it to Rory to find the last one

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2/2/2016 5:07 AM

Micahdogg wrote:

Hey VMX, is it stock style sealhead or a newer kind with circlip? I also wondered about bladders since the part number seemed ...more

It's the actual stock KYB one for a 92, they still list it in their catalog, I took a picture of the part number and the part for you.

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2/2/2016 5:09 AM

evomx244 wrote:

Leave it to Rory to find the last one

I don't think it was the last one, it's listed in the KYB/Technical Touch catalog and as far as I know if it's in their catalog they keep it in stock.

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2/2/2016 7:11 AM

Ahh, that's right. Yeah they are also on Ebay for like $65 shipped. I remember now. I took the economical route and rebuilt it since the seal and dust cover were like $20.

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2/3/2016 1:55 AM

That looks the same as the 89 YZ 250

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2/3/2016 6:23 AM

evomx244 wrote:

That looks the same as the 89 YZ 250

It could be, the book only goes back to 91 but Yamaha are great at using the same or interchangeable parts

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