1977 Columbia problems

Hey all. I have a 1977 Columbia Commuter, it is in good shape and starts right up no problems. But it doesnt go anywhere it barerly pulls me or my brother who is alot lighter on level ground. I was wondering could there be a drivetrain problem or something? I mean we have it on the stand and it runs up nicely decent power, but once its on the ground it just doesnt go. Sorry if this isnt in the right forum but I think this can be considered as moped repair.

Re: 1977 Columbia problems

What is it's current top speed? Does it have the proper airfilter/airbox? Does the transmission have fluid?

Re: 1977 Columbia problems

The current top speed....Well there is downhill which is around 25-30 mph. There is level flat road with some cohearsing it reaches a top speed of 10-15 mph. And uphill is around however fast I can push it. The airbox/airfilter are stock and cleaned. I just changed the tranny fluid today and put some new oil in. I took the silencer off and other assorted parts of the muffler and I am now runing a straight pipe its not that loud and it gained some power but not much more. The enginer runs perfect.

Re: 1977 Columbia problems

Perhaps a worn drive belt? kind of a new problem to me....

maybe a screwed up clutch, but I doubt it.

Sorry, just my 2 cents

Re: 1977 Columbia problems

Don't be sorry. I am looking for all the possibilities. I am thinking clutch also, but I want to make sure it is definately in here. I dont want to take the clutch apart and then lose soemthing when there is nothign wrong with the clutch

Re: 1977 Columbia problems

Sometimes it's difficult even for experienced people to diagnose a problem without having a lot of details.. Sometimes actually having the bike available to test is not enough..

I only have a suggestion. Take that thing to a local scooter shop and ask them whats wrong with it and get an estimate.. This should not cost you any money. Once you have their opinion you can start down the road of fixing it. You may or may not have the tools and ability to do the job.

There is always a chance that you _will_ have the shop repair it so don't get the idea (and don't let them get the idea) that you are ripping them off.

Re: 1977 Columbia problems

Sachs or Solo engine?

Re: 1977 Columbia problems

It is a sachs engine. With a bing carb. I would take it to a moped shop but there is none close to me. I mean there are motorcycle shops close by but I dont think they would work on a moped.

Re: 1977 Columbia problems

No, most motorcycle shops and scooter shops won't help you at all. If it is the clutch, you would have problems starting it too.

My usual advice for a slow sachs is to make sure that the decompression valve is set up properly, meaning that the hairpin- thing is pulling the valve closed. You can re-build the valve but it's a pain on the ass.

search the regular forum for sachs decompression and you should find something... It may have been over a year ago,,, I guess I need to haul out the digital camera and make a tutorial.

Re: 1977 Columbia problems

Ben Van Zoest /

I would look at the carburator needle valve seat, more than likely she is clogged limiting fuel delivery from the carb.

I could email an exploded view of the Bing12/15 carb.

Whenever you feel a firm clunk when moving off the centrifical clutch engages, unlikely the problem you are having.

Re: 1977 Columbia problems

ಠ_ಠ Jon Folks ಠ_ಠ /

Have you tried to run it without the airfilter/box? Or you may need to upjet it, I had a columbia commuter and it had the same identical problem. All I need was upjet it to a 62 jet, but that was too high so I took off the airbox and then it ran great!


Re: 1977 Columbia problems

there is also a chance that your piston rings may be shot, if you checked everything else like the jet and decompression valve, pull the cylinder off and check the rings

Re: 1977 Columbia problems

Steve Murphy /

I agree that the valve is a good place to start. On one of my bikes, the valve wouldn't close all the way due to carbon build up, and the symptoms were similar to yours.

An easy thing to try is this: with the engine running, squirt a little WD40 on the valve. If the engine speed changes (or if it get's quieter for a second), then the valve isn't sealing.

Of course, if the "sprung" part of the valve (where the cable feeds through) is all bent up, the problem is obvious.

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