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Resurrecting a 38 year old motorcycle

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I was looking for a fall project, and decided to take on resurrecting a 1972 Honda SL125 that had been sitting in storage for 18 years.  The bike had been stored near some swimming pool chemicals and fertilizer, and every metal surface was either rusted (steel) or oxidized (aluminum).  The bike would not have been a suitable candidate for restoring to original, but was a good candidate for "resurrecting" as a rider.

The good news was that the motor and transmission was in good shape, with 9,000 miles on the odometer.  The clutch plates were stuck, but about an hour of rocking the bike back and forth with the bike in gear and the clutch lever pulled finally broke them free. 

The carburator was beyond redemption -- the idle circuit and air bleed were too corroded to rebuild, but an ebay carb took care of that problem.  I also replaced the horn, the ignition switch, and one of the rear shocks -- again, using ebay.

So, my instructable is focused mainly on rust and corrosion removal, which took the better part of two months to complete.
 
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Step 1: Removing stuff

I began by removing the seat, gas tank, fenders, exhaust system, side covers, and the rear view mirrors.

The seat was held on by two nuts, and once removing these I simply lifted up the rear of the seat and pulled the front loose from its bracket.  With the seat removed, the gas tank (after removing the fuel line) pulled free from its front bracket.

The front fender was held by three bolts, which I wound up having to twist off (too corroded to come loose, even with plenty of penetrating oil).  I drilled out these broken bolts.

The rear fender was held on by four bolts, and once removed I could get to the bolts that held the tail light/license bracket.  The wire for the tail light unit simply unplugged from the wiring harness.

The exhaust system surprisingly came free without breaking any of the studs that held it on.

The side covers were designed to simply pop on and off, so they came off easily, and the rear view mirrors unscrewed from their handlebar mounts.

Throughout all of the disassembly process I carefully kept track of all loose parts by putting them in labeled sandwitch bags.

jesucka8717 days ago

I started working on this same style/color bike today :)

dgramo1 month ago

Bringing old bikes back to life is so rewarding. I am currently bringing a DRZ400 back to life and then I am onto a 1971 Kawasaki G3SS.

mrlunna132 years ago
Can anybody direct me on how to loosen up a seized engine?
Are there any "ibles" in here about seized engines? I looked but can't find one.
Thanks,
Mr. Lunna XIII
I know it's been 2 years but What I do use Diesel fuel Heated CAREFULLY!!!!, then pour it down the spark plug holes the replace the plugs then leave it sit over night.Then remove plugs to see if it will turn over .It works for me but sometime I leave sit for a good month in in a shop on a hot summer.
jesucka8710 months ago
I HAVE THE SAME BIKE! Thanks for the instructable!!!!!
ArcAngel271 year ago
Hey, next time you have a dent in the tank, try using a blood pressure cuff. Roll it up real tight and stick it through the fuel fill hole. Then all you have to do is pump it up tight and it will pop the dents out. It works great if the dent is in the side and not on the curve of the tank.
harthoppy1 year ago
Coke a cola and tin foil removes rust like a champ !
lingg1 year ago
For me Step #1 is: Get the thing running first (if only down the driveway and back).
Then you know wether it's worth it to spend time and money on. Having made this mistake far too many times, I have to ride it before I even clean it! Although taking stuff apart is a good way to see how it works...I would do the bare minimum to get it running first before taking it apart and painting it. Beware of the Money Pit!
Kurokami2 years ago
Your sl125 turned out really well, I hope to resurrect my '65 Honda Trail 90 for the second time since my brother blew the top end.
7070x2 years ago
looking acutely sweet there.

I own a 1978 Honda CB 100. Been on the dock for the last two weeks. Same idea: resurrecting. Bit hoping to rejuvenate or mind you, swap off, with Chinese-made of Honda GL Pro series. In my area, that Honda SL125 is used mainly for Forest Rangers. Hard to get by these days, when found, such restored...err resurrected bike with original/genuine parts costs definitely a fortune !

Super great job !
bighamms3 years ago
Can you tell me the name & cost of the system you used for the tanks interior?
Ps. its like $40 but it goes a long way!
Don't use "Kreem" it is terrible! I had to redo my tank because it started to break down. I followed the instructions to the letter. An acquaintance of my told me it doesn't hold up well to fuel which makes no sense to me but I saw it first hand. He recommended a product called "Phenol Novalac" by "Caswell". Look up their website, its a great tank sealer! I used it and am blown away how easy it was to use and the results I got!
knife141 (author)  bighamms3 years ago
I used a product called Kreem, purchased at a motorcycle shop.  Don't recall the cost.
I think the kreem is like $20 for just the sealer. Pretty sure the whole 3 step kit is $50(acid wash, conditioner, and sealer).
milesduggan2 years ago
Ugh I hate cleaning gas tanks! I am in the process of fixing up a 1975 Honda CB360(got it for $500) and all it needs is a good cleaning(carbs, gas tank, motor) and new fluids. The gas tank is a little rusty inside and I have been procrastinating on getting it done. Well looks like the July 4th weekend is as good as any.
Hello,
did you de-rusted your tank? I had the same problem. My tank was more than 40 years old. no paint, just rust. I did electrolysis on it. It looks awsome!!
You should try that if you haven't already. It really works wonders, and no fumes or harsh chemicals.
Here's the before and after. I just rinsed it with a hose.
my coffin01c.jpgHPIM2571c.jpg
Holy crap! What a difference! I did use the phosphoric acid to do my tank and it worked great, I just looked like a haz mat worker in the process. lol. Great job on your tank! Wish I would have gone your route although my results were just as good, just a little more work.
Mankut2 years ago
everything perfect, but the engine has to be either painted or sand blasted.
gonlgn3 years ago
why don't you try to sand your engine with 1000cc sand paper it will make your engine shine or buffing will much easier . . . i Like your project . .
ac-dc gonlgn2 years ago
Sanding an engine is very very tedious, better to sandblast it instead.
great ible,im looking to buy and fix a cb100 is it any good?im a no brainer on motorcycles :)
I'm currently in the process of fixing up a cb100N, and if I'm honest it's not really worth the trouble. If you've already got the bike, or it's really cheap then you may as well go for it. But don't go spending that much on a bike to start with, as almost everything will probably be rusted.

Have a look at some different bikes, before commuting to a project. The Honda cb250 is easy enough to work on, and parts are everywhere. It's a much nicer bike than the cb100N that I'm doing now.

So basically: You might as well go for it, but have a look at some alternative bikes instead of the cb100. Hope this helps, and best of luck.

knife141 (author)  mastermakoko2 years ago
I've never rebuilt a cb100, so I can't offer any first-hand advice. Good luck!
wobbler2 years ago
The finished bike looks good in its black metalwork. Nice work.
ZoDo3 years ago
Seeing this gave me the ideea to post some pictures of my 1961 Simson. After I bought it, I gave it a new paint job and I had all the rusted pieces chromed. I have some before and after photos. Unfortunately I had to sell it...used the money to buy wedding rings. But that's ok, now I have a 1986 Yamaha XV 500 SE
MRslave3 years ago
I love it, very nice
milesduggan3 years ago
Excellent job! I am buying a 1975 Honda CB360 at the end of the month and its not in as bad of shape as yours, but it will still require alot of tlc and oxidation removal. Great inspiration!
knife141 (author)  milesduggan3 years ago
This was a fun project. Good luck with your's!
lingg3 years ago
It's good to start with a 4 stroke and I would get it running good before i spent lots of time doing anything cosmetic. then you know it will run (unlike the dirt cheap porsche 914 I disassembled and never reassembled -major rust and cash)! You did a awesome job!
fegundez13 years ago
good job! I do a lot of Honda bikes and this one looks great, you got lucky with the plastic parts and the logos were there! I do hope you put new tires as well
looks way better now
tioshrek3 years ago
nice nice nice!!!
gonlgn3 years ago
does the paint you applied on your front fork didn't remove as is take preasure??
i mean if you put your weight on it does the paint stays on??
dbdanbach3 years ago
This awesome. I saw this and I had to join this website. I just bought a 1973 honda cl350 thats in similar condition to what your bike was. I've been having trouble organizing my steps, being that its my first restoration, and this is an awesome example to go off. So, thanks for putting this up.
-dan-
gfiandy3 years ago
Great job on the bike. How have the fork seals stood up as I didn't think you could get them to work on anything but a hard chrome finish and it appears yours are running on a painted finnish. Andy.
knife141 (author)  gfiandy3 years ago
You are correct, the seals will eventually fail. I have a good pair of forks (ebay) to put on when this occurs. I was going to install these during the rebuild, but found that the axle holes are too large (everything else is identical). When I get a chance I'll turn a set of bushings for them to fit the bike's axle diameter. Thank you for your comment.
samregan3 years ago
For the final paint, black for the frame and the yellow for the gas tank, by any chance what paint did you use? Brand? Spray paint or paint bucket with paintbrush?
knife141 (author)  samregan3 years ago
Rattle can for the yellow, brush for the frame.
Bapper233 years ago
Working on my gas tank this week. 1977 Kawasaki. What did you use to plug the holes before cleaning it with nuts and bolts and liquid? i went to Lowe's to find rubber plugs for the petcock holes and they didn't have any....... Also...... what about the gas cap? Thanks! Rich
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