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Offline blbiker56

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1986 RM125 Rebuild
« on: May 27, 2014, 09:56:49 PM »
Alright, so I was browsing the good ol' craigslist one day and I ran across a beautiful 1986 RM125. It definitely needed some work but was a great little bike for the price. :) $175 but it did not run at the time of me picking it up.
 
so i popped open the engine and found that the bike had been over bored to 55.5 mm and the guy tried to put a 54 mm piston in the bike, (I guess this is why it didnt run lol) Luckily the cylinder wasnt scored at all and the bike only needed a good hone to get her back in tip top shape. I ordered a Wiseco over-sized piston and the crank shaft seemed to be perfectly in spec with no play in the shaft, the rod actually looks like it is brand new!
 
So initially I though that I would have this bike just for my wife to learn to ride, but the more I worked on it, the more I fell in love with this bike. So I have come to the conclusion that I will be restoring this bike back to new again, but I will be changing just some minor details along the way.
 
Here is the sleeping beauty put away from last winter and ready to enjoy a nice little refresh, and some tear down pics.




« Last Edit: December 31, 1969, 04:00:00 PM by ' »

Offline _X_

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1986 RM125 Rebuild
« Reply #1 on: May 27, 2014, 10:06:49 PM »
Fork seal leak much?
« Last Edit: December 31, 1969, 04:00:00 PM by ' »

Offline Stusmoke

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1986 RM125 Rebuild
« Reply #2 on: June 20, 2014, 10:12:49 PM »
Fork seal leak much?

Theres a fork seal in there?
« Last Edit: December 31, 1969, 04:00:00 PM by ' »

Offline blbiker56

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1986 RM125 Rebuild
« Reply #3 on: June 22, 2014, 04:00:07 AM »
Fork seal leak much?

Theres a fork seal in there?

Well I now know there was a fork seal in there, the oil was completely black, and I have no clue when the last time the fork seals were replaced  :o
« Last Edit: December 31, 1969, 04:00:00 PM by ' »

Offline blbiker56

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1986 RM125 Rebuild
« Reply #4 on: June 22, 2014, 04:10:40 AM »
Well, It has been a while since i posted due to the website being down :(.

But I am back and I have done quite some work on the bike.

So I did a little work to the bike this past weekend, and I am finally updating the post.

 

The carburator was dirty and full of pre-mix oil in the float, so I started to do a full rebuild. I purchased a carb rebuild kit that came with all new seals, but before I rebuilt the carburator it was in desperate need to have a little cleaning performed on it, so I soda blasted the carb (which turned out really nice) and then put her back together.


 

JETTING- can someone help me with getting the jetting right for a 1986 rm125, high altitude?

This is the main reason for a copmlete engine rebuild. You can see the pitting and groves on the crank shaft before polishing it. I had the shop down the street help me polish this, Wane helped me with a lathe and crank shaft polisher. Turned out pretty good, hopefully this will fix the issues.



Here is it after the polish,, You can see one little grove that Wane just could not get out of the crank shaft, but it is so tiny that it will not be an issue. But now this thing is almost brand new, and has a new connecting rod as well.





 
« Last Edit: December 31, 1969, 04:00:00 PM by ' »

Offline blbiker56

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1986 RM125 Rebuild
« Reply #5 on: June 22, 2014, 04:19:54 AM »
Did some more soda blasting this morning, and was able to assemble the transmission along with getting the crank shaft installed. I really like the bare aluminum engine with the painted internal surface areas. For a lot of performance car engine heads this would be an extra expense to allow the oil to flow evenly, Does it really work??? I DONT KNOW, but it sure does look awesome.

I was able to find a complete engine oil seal kit that I will be installing on the bike. This will give the bike a brand new look and provide the benefits of a completely leak-less engine :) The kit also came with all copper washers to replace as well. All o-rings have also been replace.

I cant wait to get this engine going and hear it run for the first time.




I was able to get the clutch side of the engine assembled and cleaned up. My clutch tool had a hard time getting in between the clutch basket, so I was able to fabricate up a nice little tool from some left over little steel. Gave me a reason to use my new flux core welder, tuned out pretty good looking for a flux core if you ask me.

 

« Last Edit: December 31, 1969, 04:00:00 PM by ' »

Offline blbiker56

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1986 RM125 Rebuild
« Reply #6 on: June 22, 2014, 04:21:54 AM »
So the frame was stripped of all paint and then re-coated with a high gloss black and several clear coats. The paint turned out really great and is going to look fantastic with the stripped engine. I also had the chance to rebuild the rear brake and get the brake pads installed (pictures will come later). I am getting the rear shock rebuilt by a guy here in Denver hopefully this week, will need new oil and nitrogen refill.




Engine Complete and ready to be mounted...


« Last Edit: December 31, 1969, 04:00:00 PM by ' »

Offline shanes

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1986 RM125 Rebuild
« Reply #7 on: June 22, 2014, 05:29:35 AM »
it is looking great  8) 8) 8)
« Last Edit: December 31, 1969, 04:00:00 PM by ' »

Offline TMKIWI

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1986 RM125 Rebuild
« Reply #8 on: June 22, 2014, 09:39:11 AM »
Looking good mate.
« Last Edit: December 31, 1969, 04:00:00 PM by ' »
If you don't fall off you are not going hard enough

Offline Coop

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1986 RM125 Rebuild
« Reply #9 on: June 25, 2014, 12:36:43 AM »
Very nice!
« Last Edit: December 31, 1969, 04:00:00 PM by ' »
- Mike - Don't take life so seriously, nobody gets out alive.

Offline Stusmoke

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1986 RM125 Rebuild
« Reply #10 on: June 25, 2014, 04:45:53 AM »
Very wiz bang mate, but black frame? No candy blue?  :o :'(
« Last Edit: December 31, 1969, 04:00:00 PM by ' »

Offline blbiker56

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1986 RM125 Rebuild
« Reply #11 on: June 25, 2014, 03:25:40 PM »
Very wiz bang mate, but black frame? No candy blue?  :o :'(

Yes, Yes, I know... The blue frame was a very high consideration when deciding to completely overhaul the bike. I wanted to make some slight changes to the bike just to make it a bit different from all the rest.

I very much liked motodave721's bike a ton and wanted to make a little brother to his, with some slight changes as well, because this bike is super clean!
« Last Edit: December 31, 1969, 04:00:00 PM by ' »

Offline blbiker56

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1986 RM125 Rebuild
« Reply #12 on: June 25, 2014, 03:42:42 PM »
Hey Guys here is a quick update,

The bike has been put on the back burner due to another customers bike to be worked on, but...
I have rebuilt both forks and put new fork seals and some fresh oil has been put into them, they look and feel great! Also I spent a ton of time working on the radiators. They were bent up and many of the fins bashed in and not facing straight. Took a long time but the radiators are looking fantastic now and are cleaned and heated cleaned to burn off all oil deposits. I will be high head coating them with flat black to bring back the shine!(Flat Black) ;D . I also received both motion pro cables and the new UFO front fender. I should be able to polish and use all the other original plastics on the bike. I also finished the rear brake pedal.



« Last Edit: December 31, 1969, 04:00:00 PM by ' »

Offline _X_

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1986 RM125 Rebuild
« Reply #13 on: June 25, 2014, 07:31:53 PM »
Back burner?  That's where my wife puts me.
« Last Edit: December 31, 1969, 04:00:00 PM by ' »

Offline MotoDave721

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1986 RM125 Rebuild
« Reply #14 on: June 27, 2014, 01:03:30 PM »
Been off the forum for a while, we have been busy riding our newer bikes since riding season finally hit. Great reading all the posts and catching up

Awesome looking project BL, maybe we will meet up at a vintage race sometime and get some big brother little brother pics! I always wanted to do the black frame/bare engine back in the 1980's, I think some of the Suzuki fanatics might be offended but I like what I like... ;D

« Last Edit: December 31, 1969, 04:00:00 PM by ' »