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Motorcycle Repair/1983 Hondamatic and fuel overflow lines??


I have a 1983 Hondamatic motorcycle that I've never seen running. The previous owner said it ran before being put in storage.  When I move the fuel petcock it starts leaking gas through clear tubes not connected to anything.  While I was doing a Google search it was mentioned that the tubes are overflows, meant to direct gas away from the hot engine if needed.  What does it mean that gas comes out of the overflows as soon as I turn the petcock on?  I've replaced the battery, plus the sparkplugs and wire assembly.  The bike cranks but does not start, if nothing else because the gas is going out the tubes!

The owner didn't have the title, and I mistakenly believed that it wouldn't be that hard to get the bike registered anyway.  Is it worth it for me to try to get the bike running?  I am in touch with the previous owner now, but his health is poor, and I'm not sure how it will work out.  This is my first motorcycle and I don't know anything about them.  I bought the Clymer manual to try to learn.

Frank, when bikes sit for long periods of time with gas in the tank and carburetor float bowls, the gasoline will eventually evaporate and leave gummy deposits which either stick the float valves closed or prevent them from closing as they should  #2
is why your carbs are overflowing.

A complete carb clean with new gaskets/o-rings etc. will cost you about $350-400 or more at a shop. The fuel tank should be cleaned, the screen replaced and the fuel lines also replaced while the carbs are off. I worked on an earlier version of these bikes, doing a carb clean and it wasn't much fun at all. I think I had to take the rear fender loose to back the air box out far enough to get the carbs off the engine. Carb intake manifolds are also probably cracked and need replacing.

Depending upon whether other things are worn or needing replacement like tires, fork seals, drive chain, air filter and other consumables you can easily drop another $1,000 into repairs. So, unless this bike is very low miles and in really good condition, it may not be a viable project for you as a first bike. You need tools, patience, $$$ and knowledge to work on a motorcycle effectively and make it safe to ride.

You may have put your toe in the wrong end of the pool buying this particular bike, but that's all part of the adventure for a lot of us who deal in these things. After 30 years, a lot can go wrong with any motorcycle which hasn't been maintained properly.

Bill Silver

Motorcycle Repair

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Bill Silver


Need help with vintage Hondas from the 1960s? I am an expert with 250-305cc bikes in particular and most all of the other pre-91 models, in general. I do NOT claim to have a great deal of experience on Gold Wings, Cruisers, ATC/ATVs and dirt bikes.


I have owned/ridden/maintained Honda motorcycles for 35 years. I have written five books on Honda repairs and collecting. I was a service manager for two Honda shops back in the 1980s.

VJMC (Vintage Japanese Motorcycle Club) of North America

VJMC newsletter, as editor for two years and as contributing editor currently.

3 years auto shop in high school, teacher's aide in Automotive Technology in Jr. College, Diesel mechanic course in college, self-taught mechanic and automotive writer.

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