fix up help


I just got a new moped for free ,but it was sitting in this guys garage for 9 years I was wonderin if u guys could help me. It is a 1980 yamaha qt50k. The gas tank is all rusted up and I think the carberater is all froze up or somethin is wrong with my throttle cable. Also does anyone know were u can get a biturbo exsaust? All the advise would be greatly appriciated.

Re: fix up help

I saw the pictures of bikes like yours in the gallery. I assume the tank is under the seat? Is it removable or is it integral (i.e. welded to the frame)? If its removable, your best bet is probably to see if anyone here can sell you one thats in OK shape. If not, you can buy a tank liner kit from a motorcycle place, or order it from like JC Whitney or someplace. They include an acid solution to eat the rust, some solvent to clean out the acid, and a liquid liner material to coat the inside of the tank. Needless to say this is all pretty nasty stuff. It will give you chemical burns in minutes if you are exposed to it and it takes the paint right off any metal it comes in contact with. It DOES work though. But, if you can buy a tank (or even a new frame) for cheap, that's the way to go.

You will probably need to clean the carb, regardless of whether the cable is broken or not.

Good Luck!


Re: fix up help

I have had two 1980 Puch with frozen carburetors. They can be unfrozen without damage. It is not a metal to metal freezing, just the hardening of the old fuel oil mixture and there is nothing in there to rust. Just soak in cleaning fluid overnight, then gently pry the internal cylinder (sleeve) up with a screwdriver. Good luck. If the rust in your tank in not thru the wall, an extensive cleaning may be enough.

If you can remove the tank, put small stones in it and shake it around. blow and vacuum out the rust particles and you may be ok.

Re: fix up help

Get a manual from your local Yamaha dealer. See Fred's post in the main forum for trouble shooting, if your gas tank is really rusty you might try a Yamaha dealer for a new one. The cheaper alternative is to have it cleaned, see the search section for rusty tanks or take it to a competent motorcycle shop and have it cleaned, lucky for you it's removable, at least I think they are. See oldtimers post about soaking your carb, it'll be salvagable. Get some new tires and tubes as yours are in all likelyhood dry rotted. Same goes for any fuel line. Drain all the oil out of the drive shaft housing / gearbox and refill with the correct grade and quanity, this is where a manual comes in really handy. Don't worry about a biturbo exhaust until you've got it running really good.

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