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ANOTHER CB350 project Stock restore

13974 Views 124 Replies 24 Participants Last post by  fxray
Ok so here goes. My first road bike I ever owned was a 1972 CB350K4. I bought it is 1992 for $600. The thing was pretty much mint and was a blast to ride. Then a year later I bought a 1975 CB360T thinking it would be even better but it ended up being half the bike that the older 350 was. Eventually I sold both CBs and bought other bikes. I always wished I would have kept the CB350. So for the past year I have been looking for a "deal" on a mint 1970-73 CB350 (or a mint 70s two stroke road bike,..because they are cool). This Summer I saw what looked like a mint CB350 for sale on Craigslust (yes Lust because it makes you want to get stuff you dont need)if I remember correctly the guy wanted like $1600 for it. As the Summer went on I never looked at it and figured it was gone. Then early this Winter I saw it for sale again for $900. I just happened to be working in the area so I looked at it. It was more rough than it looked in the pictures and the motor was semi-siezed. My brain said not to buy it but my heart said "Buy this!" So we dickered for a while, I broke my own #1 rule (never buy anthing with a motor that doesnt run unless it is less than $200) and I bought it for $800.

Took some before pics when I got it home.
[attachment=2:3jgo2o9z]2012-12-11 16.43.20.jpg[/attachment:3jgo2o9z][attachment=1:3jgo2o9z]2012-12-11 16.43.30.jpg[/attachment:3jgo2o9z]
[attachment=0:3jgo2o9z]Bike front view before.jpg[/attachment:3jgo2o9z]


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The pics make it look good but if you enlarge them it tells a different story. :cry:

So the good:
Only 1400 origonal miles!!
Didn't have to pay for gas or shipping to get it.
It's the year I wanted
I love stock the color (no I'm not gay :x )
Many MINT parts: seat, gauges, handlebars and controls, STOCK AIR FILTERS, No missing stock parts what so ever, tires are like new (I know they should be replaced anyways), side covers, control cables, electrical seems all good, etc. Restorable parts: engine, brakes, frame, tank, front fender,etc.

The bad:
Engine is stuck or partially stuck
Lots of rust and corrosion on the bike much of the chrome will have to be replaced to make the bike mint, could be worse but could be a LOT better
Tank has a dent and someone made it worse trying to fix it
Tank is rusty inside
Mufflers are rotted out (surprise surprise :roll: )
Both carb floats are junk

So I am planning on dumping another $1000 to $1500 into the bike by the time I'm done. Not a wise financial decision I know but I'd rather know what I have for $2500 than pay $2000 to $3000 for a "mint" CB350 that a week after I buy it the motor craps out.
[attachment=1:2fgm97hx]Carbs when first opened.jpg[/attachment:2fgm97hx]
New floats. Searched high and low $50 eash most anywhere I looked. GOt these for $60 shipped on Ebay
[attachment=0:2fgm97hx]2012-12-28 17.41.59.jpg[/attachment:2fgm97hx]


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I drained the 40 year old oil and it was crazy nasty. Like a moron I got some on my hands I the stuff wouldnt come off. I'll probably get cancer or something now.
I dumped this stuff in the gear case, let it sit & sloshed it around for a week, then drained it out.
[attachment=2:3h65h78k]gear box flush product.jpg[/attachment:3h65h78k]

So I had a lot of people on here, other forums, my buddies tell me to just put Marvel oil in the cylendars and keep trying to get it to turn over. Well that seems kind of hack job to me so I ended up pulling the motor and yanking the head and jugs (jug?) off.

[attachment=3:3h65h78k]Engine almost ready to come out.jpg[/attachment:3h65h78k]

Pulled the the head off it. Lots of carbon for only 1400 miles Hmm...?? Maybe rust accumulation from trying to turn it over?
[attachment=1:3h65h78k]pistons in cylendars before.jpg[/attachment:3h65h78k]
Pistons were starting to get damaged from trying to force it to turn over. Also one top ring stuck in the piston groove.
[attachment=0:3h65h78k]Jug removed.jpg[/attachment:3h65h78k]


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Scribed to this build.............I likey.
I'll subscribe to this thread too. I enjoy watching a build where the intention is to keep it stock.

When you get the cam chain tensioner parts out, I'd be interested in some pictures. I'm curious as to their condition in your low mileage engine.

Thanks, and good luck with the project.
Wow... my brother had that same bike in the same color. He even had that same crash bar on it. Thanks much. Good luck with the restoration!
Ok so since some are interested here's an update. I have cleaned up the the clutch parts, the head and jug. Yesterday I focused on doing the head. I pulled the valves, cleaned everything (a look of carbon for a bike with only 1400 miles, hmmm)
Measured the springs and found the outer springs are within spec but the inners are slightly too short. I'm too cheap and impatient so I'm going to run these ones in it.
I wasted a lot of time on two things. 1. Trying to clean up the aluminum parts to make them clean and new looking. 2. Trying to remove old rock hard 40 year old gaskets. I tried acid cleaners on the parts. I saw a lot of the crud washing away bit it left the aluminum looking dull and dirty. I tried three applications then gave up. I tried using vinanger and that didn't do anything. I tried Simple Green and that didn't work. So I ended up trying a dremel with little abrasive wheels. It is time consuming, somewhat expensive since the wheels only last a couple minutes, and you can't get in all the tight spots. The parts do look pretty sharp though for not using a media blaster on them.
[attachment=4:20it94zk]valve cover off motor before.jpg[/attachment:20it94zk]
Acid cleaner bath,..this didn't really do much
[attachment=3:20it94zk]2012-12-29 11.49.05.jpg[/attachment:20it94zk]
Dremel abrasive wheels worked good for cleaning and removing old gaskets but only lasted about 3 minutes each wheel
[attachment=2:20it94zk]2012-12-29 19.32.58.jpg[/attachment:20it94zk]
Right side cleaned up with Demel left side not yet done
[attachment=1:20it94zk]2012-12-29 19.42.36.jpg[/attachment:20it94zk]
Reinstalling valve springs with spring tool. DO NOT buy or rent this style tool to do this job. It is a pain and BARELY can be made to work.
[attachment=0:20it94zk]2012-12-29 20.25.11.jpg[/attachment:20it94zk]


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Valves and springs installed head ready to go back on the motor.
[attachment=1:2kxpe81w]2012-12-29 20.44.56.jpg[/attachment:2kxpe81w]
[attachment=0:2kxpe81w]2012-12-29 20.45.22.jpg[/attachment:2kxpe81w]

I really wanted to pull the oil pump off the motor to clean and inspect it to make sure it was not plugged up with sludge but I'd need to remove the oil pump and clutch basket and that requires a special tool I do not have. So I just checked and cleaned the oil pump inlet screen. I'm also going ot make sure I pull the plug up on the head, kick the bike over, and make sure I have oil pumping out before I start the bike the first time.


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So yesterday I spent $97 on two piston ring sets, and two carb rubber rings sets at the Honda stealership. Then I spent about the same at Napa Autoparts buying an air tool and 3M abrasive wheels for removing stuck gaskets. The liquid gasket remover was a waste of money as it didn't do much after sitting over night only a thin layer of a gasket scraped off.
[attachment=0:3czwu3dp]2012-12-31 16.55.56.jpg[/attachment:3czwu3dp]
I dont know how well the tool is going to work since I only have a pancake compressor for compressed air. :cry:


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Today I claened off more gaskets. I've got to say the bristle 3M disks work pretty good. They are a tiiny bit more aggresive than the demel wheels I was using so you have to be a bit careful but not too bad. Also it is harder to get in some of the tight corners.
I really wish the chrome was in better shape on this bike,..hard to clean up deep rust on chrome.
Check this out. I have not tried it, and I have read that you can cause damage to the chrome parts by insufficient dilution. Yet it appears to be worth a try. It is posted all over the internet -- bicycles, cars, trucks -- nearly any sort of restoration work.

Removing rust from chrome

Also, this is a good reference:

A Primer on Rust
fxray said:
Check this out. I have not tried it, and I have read that you can cause damage to the chrome parts by insufficient dilution. Yet it appears to be worth a try. It is posted all over the internet -- bicycles, cars, trucks -- nearly any sort of restoration work.

Removing rust from chrome

Also, this is a good reference:

A Primer on Rust
That looks like it works so good that the video looks fake. How the heck is it fixing pitted rusted parts?? It's either amazing or a crock of you know what.
Well I pulled the trigger today and bought a complete stainless steel hardware kit for my motor and carbs off Alloyboltz on Ebay. I was trying like heck to stay all origonal but I broke two of the stock screw head bolts taking them out and its a paint to clean up and paint or plate all the stock ones. If I could have found someone with a plated OEM kit I would have bought that. The allens will be nice to work with though. What are people doing to help prevent a reaction between the stainless and aluminum?
I use anti seize from permatex most autoparts stores carry it.
Wyld-Bill said:
That looks like it works so good that the video looks fake. How the heck is it fixing pitted rusted parts?? It's either amazing or a crock of you know what.
Like I said, I have yet to try oxalic acid (wood bleach) as shown in the video, but I can understand how it would work the way they show. I have found the Japanese chrome to be very good quality. Sometimes a part will appear to have scaly rust as rough as sandpaper on the surface. In reality, there are some very tiny pits or pores through the chrome plating. The steel underneath has rusted. As the rust (iron oxide) forms, it expands. What you wind up with is rust that has expanded through the pit in the chrome and spread out on top of good chrome in the area surrounding the pit. If you can take off the surface rust, either mechanically or with chemicals, the underlying chrome is often still in good shape. The tiny pits will be there, but may be negligible. By keeping the surface waxed periodically, you can prevent the rust from coming back.

The problem with removing the surface rust mechanically is that the chrome is often destroyed in the process. The oxalic acid only attacks the iron oxide, not the chrome. It also evidently does not hurt paint or decals.

Here are some pictures of the exhaust shields on my CL350. These are the same parts in both pictures. I removed the rust with chrome polish, soft cloths, and lots of elbow grease, and they look acceptable as long as you don't get too close. The pits are still there, but the surface rust is gone. I believe oxalic acid would have been a much easier way to accomplish the same thing. I wasn't aware of it at the time. I will be trying it on my next project.
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I'm sure that even with nice work so far by th nice work so far by the way
YEah I'll be interested to see how it works on my rusted chrome. It seems like it is trashed to me but maybe not.

Bike is getting to be pretty stripped down now.
[attachment=2:2yljbb78]2013-01-04 19.44.04.jpg[/attachment:2yljbb78]

Picked up some more materials today and my Honda parts came in. Two sets of standard rings and two carb rubber o-ring kits
[attachment=1:2yljbb78]2013-01-04 16.16.37.jpg[/attachment:2yljbb78]

Cleaned, polished some parts with the Demel tool
[attachment=0:2yljbb78]2013-01-04 16.56.35.jpg[/attachment:2yljbb78]

I'm still on the fence whether to remove the protective coating on the aluminum parts on the bike then polish them, leave them looking dull just as they are but clean, or go for the stock look by cleaning then clear coat or clean then paint with engine paint on the engine parts.
Obviously the polished aluminum looks the best but it doesn't look stock and once you do it then you have to constantly work to keep it looking nice because the aluminum is now bare and unprotected from the environment and corrosion.


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It was hard to get in around the parts of the carbs. Once again tempted to just paint them with aluminum engine paint.
[attachment=0:2ki2xctf]2013-01-04 17.11.38.jpg[/attachment:2ki2xctf]


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