Topic: New CB Collector from Florida.

[rjrinker5]

Hi all!

I recently acquired 3 CB's. A 1978 CB750F, 1977 CB750F, and a 1973 CB500. All in kinda rough shape. But I'm optimistic that they can be brought back to life. The first 750 seems to turn over fine. The second appears the man who previously owned it was doing an engine swap because I also got a title for a 76' 750F that I believe belongs to that engine..

The CB500 is my girlfriends grandmother's. Which was the origin of my CB obsession. As her husband passed away recently we were going through old pictures and we came across one of him on his CB500. So of course I asked her what ever happened to the bike and she said "well it's sitting out back". Of course I had to take a look. After pulling 6 tarps off of it!  Finally revealed a lint filled motorcycle. Apparently her dryer vent exited right underneath the tarp and had covered the bike! We chatted awhile and she said she wished she could ride it again. So I offer to try and restore it.

I don't know much about these bikes but have been on this site 24/7 now. I have worked on my other bikes (CBR1000rr & FZ6R) before. Although nothing that will be this extensive. CB500 will be first on the list to get my feet wet. I've found a couple sites with restoration parts and "ultimate" tune up kits. I was going to start by remove/clean the carbs. Then order the tune up kit.

If anyone has suggestions on what steps I should take first please let me know. As Im a newb to this but I am a machinist and have alot of tools at my disposal.  So I should be able to do alot on my own.

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[MD]

Hello from MN,

If the bike has sat for a long time, squirt new oil in each piston and let it sit for a few days before trying to kick the engine over.

-MD

[rjrinker5]

Hello from MN,

If the bike has sat for a long time, squirt new oil in each piston and let it sit for a few days before trying to kick the engine over.

-MD

Will do! Any particular type? I have 10w-40 amsoil.. should some of that work? How much would u suggest? Thanks

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[Stev-o]

Welcome from Texas.  Cal gave you some great advice.  Along with that, buy an impact driver if you dont have one.  It is the best way to loosen engine screws without damaging the head [and having to drill them out].

[rjrinker5]

Just a few drops or a cap full should be ample. These bikes are "wet clutch" so modern full synthetic automotive oil is not suited for them. If you want to use AmSoil, use their motorcycle wet clutch formula.

As for "ultimate tune up" kits, you don't really need those. You do want new carb bowl o-rings, and some gaskets. The original brass and jets should be just fine as they are. Remove them, the emulsion tubes, and keep everything sorted by their original carb location. Clean and re-install, paying special attention to the emulsion tube orifices; they need to be completely clean and clear.

The rubber carb boots may be dry rotted, so replacement might be necessary. If they're not torn, a gentle bath in 50/50 Water/Wintergreen Oil boiled for 15-20 minutes will restore their suppleness.

A comprehensive tune up via the manual for the 3,000 Mile Service is likely all that's necessary. You can get it running, then determine if further restoration is needed (like bearings, seals, chain, sprockets, etc). It would not be unusual for the clutch plates to be stuck together after sitting for some time. Rocking the bike in gear will often free them up, then running the motor, getting the oil hot, will finish the job. Just be mindful; these are air-cooled motors! Don't let it idle for several minutes (or endlessly) without air blowing across the motor. Especially in Florida during the summer 

There's heaps more you can do, but that's plenty to-do to get the bike up. Buy yourself a set of quality JIS screw drivers. The screws are NOT Phillips, they're JIS (Japanese Industrial Standard) and it makes a complete difference on removing them without shredding them. And of course, all nuts, bolts etc are metric, not SAE 

Welcome and start a Project thread so we can admire your progress!

Thank you for such a detailed response! I'll get the oil in as soon as I get out of work! I haven't heard of any type of "wet clutch" formula made by Amsoil. I've been using their Metric 10w-40 Motorcycle oil in my CBR1000RR for years which is wet clutch with no issues. The product details described it as formulated for wet clutch applications. 

As for the carbs. I was a lil confused as to how the brass and jets would need replacing. As I've cleaned many old outboard engines and I've always just cleared all the passages and reused everything. Seems like a lot of the kits have them included for some reason though.  Fortunately I have a large ultrasonic cleaner and a soda blast cabinet to help if needed. Any suggested site to check for rebuild parts? I'm guessing the floats are plastic? I've seen some old school carbs on mercs with cork floats.. so jus askin.  Not sure what the rubber boots are but I'm sure I will understand once I remove them and will use your boiling instruction.

The bike has 11k on it so not a ton of miles.. but a decent bit of rust.. chain will definitely be replaced as it looks rough. Perhaps I can have some fun making my own sprockets if there needed. Or just because I can. Gonna have to put my logo on everything of course  it has spoked rims that will have to be replaced. Any suggested place to find them? Hubs maybe able to be cleaned up..  I ordered a new impact driver. Not sure if it had JIS included but will definitely get a set as I'd rather not snap/strip bolts.

Thanks again for the help!
Rob




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[madmtnmotors]

Welcome aboard.

What part of Florida?

[rjrinker5]

Welcome aboard.

What part of Florida?

I'm in Riverview FL.

You can simply order the bowl gaskets in the preformed style as opposed to the generic "o-ring". Easier to install and stay put while you put the bowl on.

Your floats will be plastic and use the Clear Tube method for setting the fuel level with the carbs on the bench. A bench synch (adjust slides to 1/8" gal using a drill bit or welding wire) before installing them onto the bike. The "boots" are the rubber sections from airbox to carb, and from carb to manifold. Also described as isolators.

AmSoil for wet clutch applications (like you're using) is what you want 👍

Sprockets and chains should be replaced together. Do NOT use an O- or X- ring type. These tend to be too wide and rub the engine case below the sprocket cover. The 500 has a pushrod that passes laterally through the engine to operate the clutch. This is often damaged, so inspect it carefully. And, there's a single steel ball bearing on the cover end below the adjustment cam (that wants to be lubed too by the way).

Got it running yet?

I will be ordering carbs stuff this weekend while I begin cleaning them. I will look into the bench synch when reassembling.

I'm assuming I should I go ahead and do a full oil change before starting?

I'm planning on printing as much of the online manual/literature that I see on here so I can have it in hand to read. Also probably print all the microfiche breakdowns of the bike parts for better visuals of where everything goes and there correlating names. Much like the pushrod your referring to.
I did notice a rod that attached between the frame and the rear hub that seem awfully close to the rear tire. On the right side Maybe 3/16 gap.. is that normal?

Trust me I want it running now! Lol Im already getting the typical OCD that comes when I begin a project. I have to accomplish something everyday or I get anxious. Lol

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[HondaMan]

I might suggest this step before you get to the start it up" move: when you get a good battery (or use one jumpered in from a car-sized battery) in it and oil in the cylinders for a while as mentioned above, pull out the sparkplugs and spin the engine with the electric starter to "oil it up". The oil PSI light should indicate (like a car) when it is low, but sitting unused so long may require the engine runs a while before it wakes up again (i.e., it might just stay off in any case). The idea here is: push some of that fresh oil into the crank bearings, in case there is some condensation wetness in them: this will flush out the surface rust that may well be hiding in there, and keep it from scratching the crankshaft journals. I'd give it 5-10 second "blasts" until the oil PSI light goes out, maybe up to 5 or 6 times (or more).