CH 80 Honda Scooter Running Rough?

Question

I just restored a 85 CH80 Honda Elite Scooter that was sitting for 20+ years in a garage that had gas in the tank the whole time. I took the tank to radiator shop, cleaned out the carb, an changed the spark plug and it fired right up. However it seems to be running rough. Alot of vibration when riding, acceleration isn't all that it can be. Question is it Carb/Fuel system, or is it a timing or valve issue? Currently because I think the radiator shop wasn't able to fully clean the tank properly. I have a plastic soda bottle rigged up to tubing taped on the side for a little gas tank.as temporary tank. Seems to work fine this morning ran rough. But when I went to start it this afternoon it didn't start. I let gas out of the bowl and it started up. Is the carb flooding, because of the rigged up bottle? Does the Jets need to be replaced in the carb? Does the pin connected to the shut off float need to be replaced? Do I need to try and connect it to the tank and run it off the Petcock?

Answer 1

I too am restoring an '85 ch80. There are several possible causes for the problem you have described.  You say you "cleaned out the carb"..clean it again, and be careful and thorough..all it takes is the tiniest piece of varnished fuel or particulate to cause problems. Take the entire carb apart, not just the float bowl. Clean the plug and if it still runs rough then pull the plug again afterwards and inspect...if it's black and kinda wet looking...you got a carb issue. If it's white or cocoa brown looking then inspect the intake manifold o-ring for cracks..it may be sucking air and therefore running too lean. There is a fuel enrichment valve on the carb with two wires attached...follow these wires up behind the kick panel where they can be pulled apart...ohm them with a multi-meter...should read less than 10 ohms...if more...replace (e-bay $29). Make sure the air cleaner is clean...if it looks very dirty, try running it with the element removed...if it runs ok...replace the filter ($10...bikebandit). There is also an inline fuel filter located under the tank...if that bike sat that long ...replace it...period (wal-mart $3 lawnmower section briggs and stratton or any auto parts store). Next time you drain that float bowl do it in something clean...see if there is ANYTHING in it...if there is...there's you're problem. There is also a 20 micron screen over the fuel outake in the fuel tank...access by removing the vacuum petcock..might be worth a look.

Chances are at least 80% that you're carb needs a better cleaning, buy a can of carb cleaner, get an old toothbrush and clean carefully...do everything here carefully and don't force anything. It'll run...and it'll run very well...be patient. Good luck. Oh yes...and use 92 octane fuel...91 minimum is factory recommended and for now...you want all the flash you can get. Hope this helps.

J.A. Keiling - Cumberland, MD.