Help with motorcycle repair.

[PistachioByAzul]

I'm trying to fix my dad's 1982 Honda MB5. He put about 70 miles on it before he broke his arm and stopped using it. It's been sitting in the garage for almost 20yrs, but he made the mistake of not draining the oil and gas before he put it into storage.

Anyway, so far I've disassembled and cleaned the carbureator, and put in a new spark plug & battery. What else am I going to have to do before this bike will be ready to run again? I'm thinking that I might have to end up taking apart the engine to clean it. Is that needed?

 

[Sundog]

<< so far I've disassembled and cleaned the carbureator, and put in a new spark plug &amp; battery. >>



New oil maybe. Check the gas tank to make sure the interior hasn't rusted out. Add or change the fuel filter.

 

[PistachioByAzul]

Yeah heh, new oil is a given. I don't want to do that though until I make sure I won't have to do anything else.

 

[JohnnyKnoxville]

MB 5 is'nt that the little honda 50cc moped that looks kinda like a sport bike????


Ha Ha I remember those.Its 2 stroke right????
Sounds like you got the right idea,tear apart the carb and soak it in the good juice.
Gas tank might need to be flushed too.If its 2 stroke maybe clean the reeds????
Anyway like always a service manual is your best friend.

 

[PistachioByAzul]

Yeah, that's the MB5. 50cc engine with 11,000rpm redline

It's a pretty rare bike, I've seen them go for almost $1000, and this one only has 70 miles on it.

 

[Tominator]

The good thing is that being a 2 stroke the gas and oil are mixed and actually travel throughout the bearings and rings. The only oil in the motor is in the gearbox.

If it turns over via the kick start, you are in good shape. I would take the head off and clean the rings and piston. The rings should be dirt cheap, and the shop should deglaze the cylinder for a few bucks. Check for compression with the sparkplug removed.

I'd worry about the rubber componets such as the boot that attaches the carb to the head. Make sure it is in perfect shape as a crack or hole due to dry-rot will cause the motor to seize in short order.

Fill the carb with fuel and let it set a few hours. Better yet, an overhaul kit is another dirt cheap purchase. They are very simple to overhaul.

If it doesn't run, just set it on the mantle over the fireplace.

 

[BuddyHolly]

I ran a motorcycle shop for a couple of years, and we would get stuff like this all the time..drug out of barns, hen houses, attics, etc. The carb and the fuel tank take the worst beating. A rusted out fuel tank will ruin a good bike..if you can't get a replacment and the rust keeps clogging the fuel line, and a extra strainer, than you have a problem. There is a coating you can coat the inside of the tank, but it is a pain and does not work well on severe rust.
The carb is the next biggie..it must be spotless. The varnish left by the fuel is terrible about clogging up small air passages, so when it run fine while moving, it refuses to idle..
The ignition is the next thing to check. If it has fire to the plug, than you are lucky. Most electronic ignitons will work after years of neglect. Saw one that worked after a week underwater (beer+4 wheeler + irrigation pond=one big &quot;oops&quot. If it is a points type igniton, you need to sand the points and regap them per what the manual calls for. The ignition coil will be fine unless it is visably cracked.
Don't worry too much about the oil until it runs. Run if until the case is warm and shut it down. Then change the oil..but make sure it has some first. Don't store them without oil..the clutches dry out and it ruins them. Or the stick..a lot..or both..
Good luck, send me a message if I can help..it should not be a big deal..sounds like the bike was stored inside..that is very helpful..