Started work on the Columbia yesterday. The bike is in a very sad state, and I'm really crossing my fingers on the motor.
First a correction - From what I can tell, the (bronze) bushings on the pedal crank shaft are not 3/4 x 5/8, but are in fact metric 20mm x 16mm. I must have made an error with the caliper, as the micrometer is telling me 20 x 16. 16 mm is very close to 5/8", but I don't know how I managed to get 3/4" for the OD. If you look at a genuine German-built Solo moped, they use the same pedal crank as the Columbia - so it's not surprising that the parts are metric. Parts are on the way from McMaster ($2.65/ea), with some backups coming from Grey.
The pedal crank is bent, and I'm going to try truing it up today. This should go OK.
I got the clutch & magneto covers off of the engine, and found a fair amount of wet, chunky rust under both. The clutch side is bothering me the most, as it seemed like too much crud for the actual metal that was rusting. This engine has what seems like a variator on it, and I'm thinking that the rust is (was) the return spring for the moving pulley half.
The pulley half has free axial movement on the shaft, but it will set wherever I leave it. Shouldn't it have a spring that returns it to the open position?
The starting mechanism (under the same cover) is a metal leaf spring operated by a cable. The spring has a lot of rust damage right where it flexes, and I'm concerned that it has become weakened, and will fail at some point. I need to find a spare, soon.
Lower steering bearings are totally pounded out, lots of play in the front end. Hoping these turn out to be standard bicycle stuff, and that the lower cone can be replaced. Anyone had to do steering bearings on one of these bikes?
Lastly, I'm concerned for the motor. There was no air filter on the little BIng carb (anybody have a spare?) and there was a bunch of sand in the intake area. The throttle slide has scoring on it, and I'm fearing that sand made it into the engine itself. I'll have to pull the reed block out, and see what I can feel on the inside of the crankcase. About the reed valve, how do they hold up on this engine? Are replacements available?
Oh.. one more thing. The fuel petcock is shot, of course. Is there a petcock from another ped that will fit the Columbia? Is there another source for the part?
That's all for now. Thanks in advance for any advice or info.