Hey all,
So I bought this 72 CB500 back in October as my first motorcycle, with my fingers crossed that it'd be a clean-the-carbs-out-and-get-it-running kind of project. Done on a budget. I was woefully mistaken. Retrospectively, $400 was a pretty lousy deal, but live and learn right?
The more I got into it the more I was absolutely stunned by the neglect this bike endured in the hands of its previous owners. Sadly, I didn't have my camera for a few months, so I don't have any 'before' pictures, but here's the rear wheel it came with to give an idea of its overall condition:
In addition to that massive dent, the chain was literally hanging on by a thread and the upper triple clamp was cracked. Miraculously the tank survived without dents.
As I was getting ready to try and start it after cleaning carbs, etching and lining the tank, and various other bare-minimums, I decided to pull off the oil pan to make sure everything was in order in there and clean it out.
To my dismay, I discovered gear teeth. First and second gear were totally chewed.
That's when it turned into a frame-up project. Charlie at Charlie's Place (an invaluable resource in all this) advised me to replace the entire bottom end, and sold me an engine off a bike that was hit by a car. The crankcase was cracked around the points plate area, and one of the exhaust studs were cracked off as well. Charlie knew it to be a strong-running engine with ~20,000 miles at the time of the accident. He advised me to swap all the internals into my crankcases. Here's what I did instead:
Made a patch out of 1/16" steel plate, and jb welded into place with some gasket compound around the edge to help keep water out. Still gotta take the die grinder to it and clean up that jb weld goo. I figured this wasn't a structurally important part of the case, and that this would work just fine until phase 2 of this project, in which I'll rebuild the original motor. Right now I'm at the point where I just want it on the road.
So, as per the title, it got down to a bare frame, and to keep within some sort of budget, I sprayed the thing with Rustoleum Professional (kind of an oxymoron) spraypaint. The finish came out ok, but of course it scratches all too easily. It'll get a proper powdercoat someday, but its acceptable for now, especially compared to how it was.
Here it is partially reassembled, from about two weeks ago (kindly disregard my "stand"):
Some things I did to get it to that point:
Pressed bronze bushings into the swingarm
Fitted new rear wheel, $45 shipped off ebay
New chain (looks like its a link too long... will be remedied)
New upper triple clamp
New Bridgestone BT45 tires
Ground the brace off the front fender (it was in rough shape)
Replaced most bolts with stainless hex bolts, polished the rest with wire wheel on 6" bench grinder (probably the most-used tool on this project
)
Sprayed the rusted-beyond-help bits (like the fork caps) with silver caliper paint
Rebuilt the head bearings with new 1/4" balls (surprisingly, the bearing races were damn near perfect) Will replace with tapered roller bearings when funds and time loosen up.
Lots of lazy polishing
Here's the progress since then:
Embarrassing to even mention this with the likes of Mec, FunJimmy, and so many other masterful fabricators around these parts, but I turned myself a new stainless clutch-actuating rod (don't know the more dignified name for it), old one on right is a little bent and chewed up:
Bit the bullet and bought a Dyno electronic ignition. I'm a little disappointed in myself for not taking the time to adjust the points, but for now I just wanted the set-it-and-forget-it simplicity, in the ignition at least. I timed it with the pulling the plugs and setting them on the engine block trick, and with that I'm delighted to say that I actually got the thing to go around the block under its own power today!
This might have been jumping the gun, its got no mufflers on it and I was definitely being a bad neighbor with the noise, also its (as best I can figure) running way too rich. Spewing lots of smoke, and the motor cuts out if I close the choke all the way. But it runs! And I gotta say, just the sound of it filled me with the kind of childlike excitement that sometimes gets all too few and far between. Motorcycles are pretty great.
Anyway, about the carbs, I'm gonna try backing off the air screw all the way, see if that helps, maybe try lowering the needle some (but, that doesn't really take any effect at idle does it?). Any other basic suggestions? I have no idea what size jets are in them. How does one determine the # of the size?
What's left to be done:
New seat cover, and probably aftermarket side covers.
Rebuild front brake master cylinder and caliper. Fired the piston out of the caliper yesterday with the air hose. Kaboom:
Pitted to high heaven. I'm going to turn a new one out of 303 stainless. About that, I haven't taken the micrometer to it yet, but anyone know what kind of tolerance this wants? Is within .001" acceptable, or does it need to be
exactly the OEM dimensions? Also, anyone know why the OEM pistons aren't bored out on the pad side? It looks like there's an insert pressed into them there, is this trying to dampen brake squeal or something? Mine will reassemble these, sold at Charlie's Place:
Now the exhaust...
The chrome on the headers was too pitted, so they got sprayed with Flameproof flat black, not original but I'm pretty happy with the results. Here's the state of the mufflers though:
Now quality exhausts are wildly expensive. I'm already WAAAY over my original "budget," so I'm thinking of purchasing or fabricating some baffles. I really need some insight and advice here. I sawed off the flared, rusted out megaphone bits of the current mufflers and am left with a 2.5" straight tube. Any aftermarket baffles that you guys can recommend for this application? If there's nothing off the shelf that will work, or if its too expensive, I'd be into fabricating something if anyone can recommend a simple, functional design to work from.. Input would be greatly appreciated.
Huge thanks to you all as the FAQ and the rest of the forums here have been incredibly informative and inspirational. And thanks for taking a look at my project.
