1986 Yamaha YZ250S

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3/29/2018 10:25 AM
Edited Date/Time: 3/29/2018 10:43 AM

Got a basket case bike that I have as my winter project.
Was one almost complete bike and a couple of engines and a frame when I got it.
This is what I started with:

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Tore it down and got the frame cleaned up, welded a few cracks and painted:

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Rebuild began, all bearings etc replaced.
Öhlins shock rebuilt
Spokes etc replated
Wheels rebuilt
Some photos of the process:

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Engine getting new bearings, and overhaul of the crank.
Transmission was good
Doing some porting to the cylinder after reading Eric Gorr's book

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The bike as it sits now.
It will be a Broc Glover "replica"
Since it's near impossible to get any parts, exhaust etc to do a proper replica, I will build it to look like Glover's 86 bike.

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3/29/2018 10:53 AM

Nice, very nice. I didn't know Yamaha went to standard spokes in 86.

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Yeah, I have no clue !!!

3/29/2018 11:13 AM

nicko-31 wrote:

Nice, very nice. I didn't know Yamaha went to standard spokes in 86.

Thanks!

The rear spokes are Z-spokes, and a first time dealing with that for me.
Front spokes are more like standard spokes

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3/29/2018 12:11 PM

Don't let the Z spokes scare you, there actually easer to work with than standard spokes. The cylinder pic that you show of the intake side is the same extra left side boost port Eric added to one of my 85 125 YZ cyclinder also. It really cured what I believe was probably the slowest 125 in 84/85.

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Yeah, I have no clue !!!

3/29/2018 12:51 PM

nicko-31 wrote:

Don't let the Z spokes scare you, there actually easer to work with than standard spokes. The cylinder pic that you show of the intake side is the same extra left side boost port Eric added to one of my 85 125 YZ cyclinder also. It really cured what I believe was probably the slowest 125 in 84/85.

Yes, I got the hang of it after a while, and rebuilding the wheel with Z-spokes was actually a cool experience. Took me some tries to sort out the order the spokes had to be installed into the hub.
Sweet, nice to know that Eric's advice works that good.

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3/29/2018 2:51 PM

Beautiful work!
I had both the 250 and 125 brand new that year...I loved those bikes..

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2020 YZ450F
2006 YZ125
2013 YZ 250F special edition
2017 YZ 250
2015 YZ 250f soecial edition
2019 KTM 85 big wheel
1979 YZ 250

3/29/2018 11:44 PM

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I loved mine, that was me on the 250 at the Mildura supercross in 1986
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2020 YZ450F
2006 YZ125
2013 YZ 250F special edition
2017 YZ 250
2015 YZ 250f soecial edition
2019 KTM 85 big wheel
1979 YZ 250

3/30/2018 1:12 AM

PJRAUS wrote:

Beautiful work!
I had both the 250 and 125 brand new that year...I loved those bikes..

Thanks!
Awesome photo of you from the Mildura Supercross!

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3/30/2018 2:57 AM

Bike looks sweet already.

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3/30/2018 3:25 AM

BenG wrote:

Bike looks sweet already.

Thanks!

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3/30/2018 6:05 PM

Nice. I got one just over a year ago. Was sitting in someones garage with very little done to bring it back to nearly new. I havent had the nerve to take it in the dirt yet.

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3/30/2018 6:29 PM

Getting the gas tank white is a big delema I've been trying to resolve. How did you get yours so white Ove ?

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Yeah, I have no clue !!!

3/30/2018 10:08 PM

nicko-31 wrote:

Getting the gas tank white is a big delema I've been trying to resolve. How did you get yours so white Ove ?

I cleaned it several times, but could not get the yellowing out.
I ended up buying a white perforated tank decal from Evo-mx.

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3/30/2018 10:12 PM

propp2531 wrote:

Nice. I got one just over a year ago. Was sitting in someones garage with very little done to bring it back to nearly new. I havent had the nerve to take it in the dirt yet.

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Nice one!
I can understand the hesitation to bring it out into the dirt, have the same dilemma with my build...:-)

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3/31/2018 5:14 AM

Photo great . I did the same thing. There's a chemical process that can be used ,it's on a few Internet forum's.

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Yeah, I have no clue !!!

4/15/2018 4:09 AM

Billet Alu water pump impeller. A good upgrade from the stock plastic one.

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Got the bottom finished, now waiting for the cylinder to get back from the machine shop. (Boring out to .50 oversize)

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7/4/2018 6:31 AM

Out in the sun for the first time since last summer.
Some finishing touches and she is ready.
Have to weld up a new exhaust , install radiator hoses and some other stuff, but she is getting there

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7/12/2018 11:34 PM

Awesome bike!!!

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7/13/2018 1:06 AM

chuckie108 wrote:

Awesome bike!!!

Thanks!

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7/17/2018 9:01 AM

Over, have you been able to race or ride the bike yet ?

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Yeah, I have no clue !!!

7/17/2018 1:27 PM

nicko-31 wrote:

Over, have you been able to race or ride the bike yet ?

No, still not finished with the exhaust. I will post a ride report when I have .

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9/12/2018 11:28 PM

And this is the bike completed.
Been a fun project
Hope you enjoy:

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9/13/2018 8:54 AM

Bike looks great Ove. I had issues as well with my 33 year old carburetor and opted for a 38mm round slide Mikuni on my 1985 125-N. Worked well for me and it was only 100.00 In the US on ebay.

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Yeah, I have no clue !!!

9/14/2018 1:59 AM

nicko-31 wrote:

Bike looks great Ove. I had issues as well with my 33 year old carburetor and opted for a 38mm round slide Mikuni on my 1985 125-N. Worked well for me and it was only 100.00 In the US on ebay.

Thanks!
Yeah, I did do a cleaning and used the best parts i had from two carburetors, but look like I have to rebuild once more.
(Not sure what happened to my post where I wrote about the flooding of the carb..?)
Anyhow, the bike fired up and ran absolutely great, and had a strong midrange as I hoped it would have after the Eric Gorr mod I did to the cylinder, with the Boyesen Reeds.
Will install a complete FMF exhaust, and I think that will help as well.
Thanks for the tip on the carb, will look into something like that if I can't get the one I have to work.

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9/27/2018 11:41 AM

Ove wrote:

Got a basket case bike that I have as my winter project.
Was one almost complete bike and a couple of engines and a frame when I got it.
This is what I started with:

Photo

Photo

Photo

Tore it down and got the frame cleaned up, welded a few cracks and painted:

Photo

Rebuild began, all bearings etc replaced.
Öhlins shock rebuilt
Spokes etc replated
Wheels rebuilt
Some photos of the process:

Photo


Photo


Photo


Photo


Photo


Photo


Photo

Engine getting new bearings, and overhaul of the crank.
Transmission was good
Doing some porting to the cylinder after reading Eric Gorr's book

Photo


Photo


Photo


Photo


Photo

The bike as it sits now.
It will be a Broc Glover "replica"
Since it's near impossible to get any parts, exhaust etc to do a proper replica, I will build it to look like Glover's 86 bike.

Photo



What pegs did you put on your bike? Mine still has the stock and I'm looking for bigger more modern pegs

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9/27/2018 9:34 PM

Great job on the resto! That is one of my favorite color combos!

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9/30/2018 9:09 PM

You did a great job. That bike looks awesome.

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10/21/2018 9:14 AM
Edited Date/Time: 10/21/2018 9:16 AM

propp2531 wrote:

What pegs did you put on your bike? Mine still has the stock and I'm looking for bigger more modern pegs

Sorry for late answer Propp2531
I bought a set of Super Stock pegs from Parts Europe P/N 277311 (Parts Unlimited)
They are wider than stock, and looks almost stock.

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10/21/2018 9:16 AM

Micahdogg wrote:

Great job on the resto! That is one of my favorite color combos!

Thanks!
My favourite color on Yamaha's too!

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10/21/2018 9:17 AM

wfoskir wrote:

You did a great job. That bike looks awesome.

Thanks! Glad you like it.

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