1976 CB-125S

Jettabor81

Pho King Unbelievable
Hello,

I'm new to bike restoration and this forum in general. I have a 1976 CB-125S - it's my project bike. I just discovered that I have a rusty fuel tank. I was wondering if anyone could clue me in as to what my best option is for replacement. There is a place called Bike Boneyard in Montana - and they claim to have replacement parts, but I'd be buying them sight unseen. Not sure if this is the best plan?

Thanks in advance -

Jet
 

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How rusty is it??
You may have options if it is not rusted through.......like Metal Rescue, it will remove the rust
 
Well, the thing is - I am working on this bike with a neighbor who has significant repair experience - but not much patience for people who don't store their motorcycles with a full tank of gas. The fella I bought my Honda from was pretty lax when he put the bike in the garage and it sat for 3 years collecting dust before I bought it.

When I examined the bike it didn't look like my tank was rusted through at all. However my neighbor says that there are key places on a bike's gas tank to look for rust that indicate a problem: near the seals and if there is a milky film inside. I didn't see these signs - but he looked it over better than I did - he thinks restoring the tank with Metal Rescue is a bad idea since there is a small chance there will still be particles that get into engine + acid can fuck up seals... He thinks it is just way better to start fresh with a salvaged or OEM gas tank. The trouble is I can't seem to find any OEM gas tanks languishing in any warehouses -- all I can find are gas tanks in salvage yards - the kind this dude will probably reject for the same reason he dislikes my tank.

Maybe the larger question here is: is my neighbor over cautions?

Thanks!
Jet
 
He may think that its a bad idea but many of us here if not all of us would disagree with him since many of us have removed rust from a tank easily and used it successfully with out ruining our motors. Its cheaper and easier to just de-rust the tank and seal it if need be which I have done quite a few times on bikes that are still running today without issue and to be extra safe, I installed an inline filter from the tank to the carbs with not a spec of dirt or rust in it at all

Sorry, I don't know where you would find a tank like that so I can help you there But if you want to have more info on cleaning and sealing a tank....there are plenty of threads on this forum on the subject
 
It'd be helpful if you could post a few photos that show the condition of the tank. In particular, at the outside bottom edges where it's welded, especially toward the rear, and of the interior looking through the filler opening.
 
Bike is currently off site a few miles down the road at neighbor's house. But can take some pics when I visit with him tomorrow and post them up.

At this point I am more or less wondering if my neighbor is trying to get out of helping with the project. He left a message telling me that since all the rubber on my bike needs replacing and it was stored without gasoline in the engine - and since it needs a new muffler; I'd be better off looking through the classifieds for a new bike...

I disagree - I don't think newer automatically = better. I love the classic feel of the design. I do not want a 2010 Kawasaki Ninja (as my neighbor suggested). As near as he can tell there is nothing wrong with the engine or transmission. There are no ominous leaks.

He just opened up a shop and we are in a farm community - so he is already inundated with ATV repairs and the like. My plan was to have him analyze what needs fixing - then evaluate what's too hard to fix myself and have him do it - then plug away at the rest with my shop manual.

Maybe I should cut my losses and start working on it myself... My repair cred is not exemplary tho. The only thing mechanical I've helped to repair is our old Sears riding lawn mower.

If anyone could offer a reality check, that would be greatly appreciated.

Best Wishes-
Jet
 
These old Hondas are quite easy to restore due to readily availability of parts, service manuals, and forums like this with all the advice you will need. If you want to restore it, it can easily be done, the only thing to consider is what you want to spend on it, as that will largely determine the results.

Anyways, as for your gas tank, the cheap way to do it is to fill it up with vinegar and wait a day or 2. Throw in something like a few nuts and bolts, a piece of chain, or personally I like to use one of those stainless steel scrubbing pads. With the tank full of vinegar and something inside the tank, shake it around to knock rust loose every so often. Drain it and rinse it out with water real good, and dry it with a hair dryer or something like that.

Metal rescue works better than vinegar, but is more expensive. The difference between to two is that vinegar will flash rust (begin to very lightly rust right away) once you drain it, and metal rescue won't.

You can coat the inside too with RED-KOTE for instance. I've never done this because I've never had a gas tank leak after cleaning rust out this way.

Once your tank is clean, clean carburetor, new gas line/ filter, new engine oil, you will probably be able to fire it up.
 
Jettabor81 said:
Bike is currently off site a few miles down the road at neighbor's house. But can take some pics when I visit with him tomorrow and post them up.

At this point I am more or less wondering if my neighbor is trying to get out of helping with the project. He left a message telling me that since all the rubber on my bike needs replacing and it was stored without gasoline in the engine - and since it needs a new muffler; I'd be better off looking through the classifieds for a new bike...

I disagree - I don't think newer automatically = better. I love the classic feel of the design. I do not want a 2010 Kawasaki Ninja (as my neighbor suggested). As near as he can tell there is nothing wrong with the engine or transmission. There are no ominous leaks.

He just opened up a shop and we are in a farm community - so he is already inundated with ATV repairs and the like. My plan was to have him analyze what needs fixing - then evaluate what's too hard to fix myself and have him do it - then plug away at the rest with my shop manual.

Maybe I should cut my losses and start working on it myself... My repair cred is not exemplary tho. The only thing mechanical I've helped to repair is our old Sears riding lawn mower.

If anyone could offer a reality check, that would be greatly appreciated.

Best Wishes-
Jet

I agree with your suspicion that your neighbor is not really interested in helping you restore the bike. Based on the crappy cellphone photo, it appears very restorable to me. Make no mistake, any restoration project will be fairly involved. Your neighbor knows this, and is trying to steer you away from what he anticipates as becoming his headache to resolve. If you really like this bike and want it restored, assure your neighbor you're willing to assume the lion's share of the work and will just rely on him for occasional advice and technical assistance. Follow the advice others have already suggested to clean and seal the tank. Not a difficult job to do and there are plenty of YouTube vids for reference. Once the tank and carbs are cleaned, oil and filter replaced, battery charged... try to get it started. Make sure tires are in decent shape and get it out for a ride. If you can get it to a rideable condition, you can start to assess what needs further work and set priorities. Post your work here and folks will help you keep it going. Good luck, you can do this!
 
Several things here. Are you partners with the neighbor? If not, take it home, this is a simple bike with simple systems and easy to work on. Second, this will need to be a labor of love, 125's don't bring $, so if you're not in love with this bike, sell or trade it for something a little more practical and market worthy. This could get expensive quickly, so you need to figure how to save as much of the original bike as possible. I agree with others, your tank could probably be saved. My BSA's tank was in horrible shape, but had it hot tanked and welded for $80. much cheaper than replacements. Have you actually sat down and made a list of what needs repair? Priced the parts out? You don't want $2k in a $900 bike. Is the paperwork sorted? A plan can keep you from getting burned out. These bikes are so simple you can do most of the work with simple tools and a manual. If this was a multi carb. multi cam bike, getting help works, but a single 125 is as basic as you can get and a great learning experience and you don't need to knock heads with somebody who has a different agenda. If you get stuck, he's still down the street, but I'll bet you breeze through this...
 
Go get the bike. The 125 is as simple a machine as you'll ever find. With some patience and help from the friendly assholes here on DTT I'm sure you can accomplish your goal. BTW, what is that goal? Restoration? Cafe? Something else?

As far as the tank, post pics. As stated above, there are a few different ways to repair a rusty tank. Just depends on how rusty it is.

125 parts are plentiful and super cheap in comparison to some other bikes out there.

I've rebuilt a 125 motor from the bottom up (as have several members here) so feel free to ask any questions you may have. I also may have a line on some cheap parts for you if needed as well. I'll have to put a call into my buddy with the long forgotton 125 in the back of his parents garage. Lol.

Again, go get the bike and get to work!
 
Yes. I agree with you all. The goal is not to resell this bike, so I am not too worried about making my money back, I just have feelings for it and I love experimenting and learning new things. I think it would be best to just go retrieve my bike from the neighbor and do what I can with it myself. (The neighbor and I are in no way partners)

Originally I simply wanted to restore the bike back to its 1970's glory. However I've been looking at youtube recently and damn... https://www.youtube.com/watch?v=0a5sL5WDnHs

So far the things I've taken apart and put back together successfully have been limited to: typewriters, lawnmowers, dishwashers, cell phones, automotive headlamps, and one lawn tractor. My grandmother was an airplane mechanic during WWII in the Marines and I'm hoping I've inherited some of her better genes, this should be a good test.

I did go back to his shop, and while I couldn't get a good angle to take a picture of the gas tank where the rust spots were starting to show through (he had many snow machines and ATVS crowding around my bike) I did get the chance to verify that the rust blooms were in the areas described by iatethepeach "At the outside bottom edges where it's welded, especially toward the rear, and of the interior looking through the filler opening." To my neighbor's credit - I do think, after closer examination, that my gas tank was rusting from the inside out.

While I 100% think I could have easily derusted the inside of the tank with Metal Rescue, or chains and vinegar, and a good scouring. I decided to go with a replacement tank, the price seemed right and I liked the look of the tank and did not want to reseal. The Bike Boneyard in Missoula, MT. had a pristine replacement tank for $75.00 and an equally pristine exhaust system, also for $75.00. They came in the mail last Saturday. I'm including some more "crappy cell pics" lol. I'm also including the parts list my neighbor came up with (great suggestion ApriliaBill).

Von Yinzer - If your buddy does have any spare parts, please let me know, that would be great!

Thanks Again -
Jet
 

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Yep, good decision to buy a new tank. I had a pretty bad tank on my XL and ended up spending 6 hours trying to braze it up...and I just ended up buying a new tank in the end.

I think its a good call to get the bike back and do the work yourself. You will learn a lot and you can make sure the work is done right and up to your standards. Should be a very simple little bike to work on.
 
I see front brake cable on the list, if that means you have the mechanical caliper vs. hydraulic do yourself a favor and upgrade that instead of new pads and cable. I'm pretty sure there is a better one out there that will swap right in. I don't see a master cylinder in your pic either so I bet it is the mechanical one. welcome to DTT if you can rebuild a mower and a lawn tractor this little bike will be easy for you.

Cheers.

Maritime
 
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