Project bike: 1986 Honda CR125R

JMX82
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3/5/2016 11:15am Edited Date/Time 11/12/2020 7:01am
Got myself my first vintage project bike yesterday. Bike is relatively good shape has been sitting years in storage. I can't believe how light and small bike feels compared to my KTM 150SX. Rims and frame are straight and it seems to be really solid bike to start rebuild













Biggest issue in the bike is badly corroded engine side case. I think this one cannot be repaired anymore. If you know place where I can find new side case I would be very much interested.







One thing that was missing is Atac exhaust chamber. Does this motor work well without it?





Also choke knob and engine head stays are missing



It also needs new seat cover



Front brake doesn't work but forks seemed to be in good shape



Plastics and radiators are in pretty good shape







I wonder if this will hold gasoline...



Rear shock is in really bad shape. I hope it can be rebuilt.





Clutch basket and plates seemed to in good shape



some bits and pieces



Air filter looked good







|
billyslad
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3/6/2016 2:32am
All looks quite original and there

You have quite a task ahead there is a Facebook group for honda cr 1986 that has a guy on there Russell who is from Australia who has manufactured aluminium water pump cases
JMX82
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3/6/2016 8:49am
I started to dismantle the bike today. All the bolts came out surprisingly easy although they where really rusty. The bike is mostly original but there are some redneck repairs



I noticed that exhaust silencer is aftermarket version





Exhaust pipe is in decent shape



Radiators have few repairs. I hope they don't leak



Tank repair job looked bit sketchy





Frame is bit rusty but I haven't found any cracks yet



Piston looks like it is almost new. It's 1 mm oversize Prox piston







Cylinder on the other hand had a nasty groove. I think it has to be re-bored.



Cylinder head has some small marks, but I think it's still usable



Self made Atac cover to replace missing chamber...



Reed valve is in really good shape



Carburetor was filled with black goo and has weird self made choke knob



Plastic parts in the box waiting to be cleaned



Does anyone know if I can find a service manual for this bike online somewhere?





crfman250
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GR
3/6/2016 9:32am
Hi there !
Nice find real nice bike and so OLD school!
It was my first Dirt bike!
I still have it restored and i was one of the lucky guys that found one of the last NOS right hand covers from MIdWESTACtionCycle back in the mid 2000's!
I used the Clymer manual for it but now you buy online a complete manual by Trade bit

https://www.tradebit.com/filedetail.php/278295916-cr125r-service-manual…
just for 5usd and it really works

Wink
billyslad
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3/7/2016 1:22am
You will find a workshop manual on eBay which will be a familiar friend for parts
A few people disposed of the Atac chamber as it wasn't the most effective unless everything else is perfect

The Shop

TTperra
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3/7/2016 4:06am
Do you live in Finland?

I have a CR125 -86 i will part out.
It have atac chamber and crankcase cover, but i have not got time to disassamble yet, so I dont know condition of the parts..
Send me a list of what you need and i see what i have
JMX82
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3/8/2016 8:19am
I think hot exhaust pipe must have become loose some point and burned hole to the tank. It's amazing that hole bike is not burnt when that happened.

I haven't completely decided yet but I kind like the stock -86 look.

JMX82
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3/8/2016 8:33am
TTperra wrote:
Do you live in Finland? I have a CR125 -86 i will part out. It have atac chamber and crankcase cover, but i have not got...
Do you live in Finland?

I have a CR125 -86 i will part out.
It have atac chamber and crankcase cover, but i have not got time to disassamble yet, so I dont know condition of the parts..
Send me a list of what you need and i see what i have
Yes I live in Finland. I'm currently on a work trip abroad and haven't yet dismantled hole bike so I don't know yet all the parts that I need.

These are the parts I know this point I will need:

Clutch cover
Atac chamber and butterfly valve
Gas tank
Cylinder head stays
TTperra
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3/8/2016 9:52am
I will look at it by the end of the week.

I agree, the stock -86 looks really nice.
jtracing6
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Dundalk IE
3/9/2016 3:38pm
That is a stock silencer, OEM. The best manual to get is Honda original, they pop up on eBay.
I have a lot of NOS small parts for this bike. I too have another that I am breaking for parts.
You could make it look like this!



2
1
JMX82
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3/13/2016 10:11am
This marking made me believe that the silencer is aftermarket but guess it is just original manufacturer logo



I removed the engine today from the frame. Still no bolts where jammed or stripped







Clutch plates where almost like new and clutch basket was in great shape





Slosh 112
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Mackay QLD AU
3/15/2016 3:29am
Sankei is an OEM supplier.
2
3/18/2016 6:34am
I had one! That was actually the first brand new bike I ever bought. What I remember mainly is that the forks were not very good (stock), but the stock motor made a LOT of power - especially off the bottom.
JMX82
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3/19/2016 8:44am Edited Date/Time 3/19/2016 8:48am
First parts for the bike arrived today:

Nice aluminum HRC replica clutch cover from UK




and unused HRC pipe from Sweden that I happened to find while I was searching parts from the internet.


I discovered that flywheel threads are bad ruined my flyweel puller while I was removing it. Maybe I have to find new flywheel for the bike.



I splitted the cases with my self made tool. Crankshaft and gear box bearings must be replaced but the gears and shifters looked really good for an old bike.









I have heard some mixed reviews about the Atac chamber. Some say that bike runs well without it and others say that you loose lot of low end power without it. I haven't decided yet should I get missing Atac chamber parts or just run the bike without it. Any input of that would be appreciated.
MaxPower
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3/20/2016 8:18am
jtracing6 wrote:
That is a stock silencer, OEM. The best manual to get is Honda original, they pop up on eBay. I have a lot of NOS small...
That is a stock silencer, OEM. The best manual to get is Honda original, they pop up on eBay.
I have a lot of NOS small parts for this bike. I too have another that I am breaking for parts.
You could make it look like this!



This is still one of my favorite bikes I've seen on Vital.
JMX82
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3/25/2016 8:49am
More parts for the bike arrived. Engine gasket set and intake manifold



I removed all the parts that where still mounted to frame.









One handlebar mounting bolt was giving me a bit hard time but eventually it came out. This was first bolt that gave me trouble with this bike. I had to cut the handlebar crossbar to get better access to mounting bolt that was stuck and rounded.



To my suprise steering stem bearings where greased and in great shape. I think that I'm not going to replace them.



Frame ready to be sandblasted and painted. The frame components are so much lighter than current bikes. I think supercross is the reason why modern bike frames are so overbuilt today compared to older bikes.




billyslad
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3/25/2016 11:58pm
Have you thought about an 87 swing arm and rear disc conversion
JMX82
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3/26/2016 2:31am
I think I'm going to use stock drum brake because for some stupid reason rear disc brakes are banned from classic racing in Finland.
billyslad
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3/26/2016 6:16am
Ok see if you can get some cr 250 forks on
spend you money on suspension
1
JMX82
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3/26/2016 11:34am
I will try first get the original suspension rebuilt. My budget for the project is already getting out of hand... I read somewhere that later model XR forks might also work with my bike.
JMX82
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4/3/2016 5:22am Edited Date/Time 4/3/2016 5:47am
Found almost unused Atac chamber and exhaust manifold from Finland and got seal kit for the engine from Ebay.



There are slight differences between exhaust manifolds but it seem to fit to the cylinder and and exhaust pipe. The atac chamber itself wont fit to old exhaust manifold so i have to use new one.










jtracing6
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4/3/2016 10:45pm
You probably have a 1985 ATAC manifold.
JMX82
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4/4/2016 4:30am Edited Date/Time 4/4/2016 4:30am
I think you are right. -85 and -86 have different part for Atac manifold although the look the same in parts diagram. -86 manifold assembly part number is 18350-KS6-000 and -85 part number is 18350-KA3-760. I don't think that makes too much difference tough and the parts are in great condition so I will use them on the bike.
anniebertmojo
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California, CA US
4/4/2016 7:08am
I don't know if this helps?, but Johnny O's actual 86 MXDN works Honda he rode (it lives at American Honda's race shop). Thought you might like to see. Good luck on the build. Looking forward to seeing the finished result.

























2
JMX82
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4/4/2016 12:47pm
Thank you very much for the inspirational pictures
sands-cr250
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Edwardsville, IL US
4/4/2016 7:46pm
What a great year! Excited to see this one come together.

4/4/2016 8:08pm
JMX82 wrote:
Got myself my first vintage project bike yesterday. Bike is relatively good shape has been sitting years in storage. I can't believe how light and small...
Got myself my first vintage project bike yesterday. Bike is relatively good shape has been sitting years in storage. I can't believe how light and small bike feels compared to my KTM 150SX. Rims and frame are straight and it seems to be really solid bike to start rebuild













Biggest issue in the bike is badly corroded engine side case. I think this one cannot be repaired anymore. If you know place where I can find new side case I would be very much interested.







One thing that was missing is Atac exhaust chamber. Does this motor work well without it?





Also choke knob and engine head stays are missing



It also needs new seat cover



Front brake doesn't work but forks seemed to be in good shape



Plastics and radiators are in pretty good shape







I wonder if this will hold gasoline...



Rear shock is in really bad shape. I hope it can be rebuilt.





Clutch basket and plates seemed to in good shape



some bits and pieces



Air filter looked good







The best bike I ever owned,
Modified forks and shock with heavier springs, pro circuit pipe without ATAC,
One tooth smaller rear sprocket,
The head had been modified tightened squish.
Holeshot beast.
jhkinin
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Location
Southern California, CA US
4/4/2016 9:25pm
I just finished a low budget restoration on this same bike. What a great bike and a blast to ride.





wfoyz250
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Spring, TX US
4/5/2016 4:56am
Nice work!
I had one of these back in the day. Great bike!!
jhkinin
Posts
74
Joined
11/24/2009
Location
Southern California, CA US
4/5/2016 5:50am
Besides an oversized piston and some mild porting; the motor is stock. I got the bike with the DG pipe and silencer. The stock pipe and ATAC was long gone. It was neglected when I got it (shocking I know). Had the classic duct tape seat, wood block chain guide, and one silver and one gold rim. The good was how complete the rest of the bike was including a clear CA title. My idea of a budget build; I have a new top end, rebuilt the shock, fork seals, doc fees, many hours of elbo grease, and a lot of eBay savaging for an all in price of $1,380 including the purchase of the bike. Now is the bigger question; to keep it or sell it?
jhkinin
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Southern California, CA US
4/5/2016 10:41am
JMX82 wrote:
First parts for the bike arrived today: Nice aluminum HRC replica clutch cover from UK [img]https://p.vitalmx.com/photos/forums/2016/03/19/128539/s1200_2016_03_19_12.46.41.jpg[/img] [img]https://p.vitalmx.com/photos/forums/2016/03/19/128541/s1200_2016_03_19_12.47.12.jpg[/img] and unused HRC pipe from Sweden that I happened...
First parts for the bike arrived today:

Nice aluminum HRC replica clutch cover from UK




and unused HRC pipe from Sweden that I happened to find while I was searching parts from the internet.


I discovered that flywheel threads are bad ruined my flyweel puller while I was removing it. Maybe I have to find new flywheel for the bike.



I splitted the cases with my self made tool. Crankshaft and gear box bearings must be replaced but the gears and shifters looked really good for an old bike.









I have heard some mixed reviews about the Atac chamber. Some say that bike runs well without it and others say that you loose lot of low end power without it. I haven't decided yet should I get missing Atac chamber parts or just run the bike without it. Any input of that would be appreciated.
Any info on where to get that clutch cover?
I'm sure the price will not be good with the "budget" build.

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