Fuel Mixture/ Suzuki FA50

hello all, need a little help here. My parents have an FA50 they've had for many years, I forget what year but I think around 81. It ran fine when they first bought it but over the years it had started to have less and less power and start to really smoke pretty bad. It's been sitting for several years but we've been thinking of getting it running again to take to the racetrack for a pit-bike.

Anyway, talking with some friends, they have heard of the auto-mix portion of this bike having problems and causing the symptoms I'm having. They thought there was a way to disable the auto-mixture system and just mix the fuel like any other 2-stroke so I started taking it apart and realized it was a bit more complicated than a simple mixing valve.

Is there a way to do this, how and where can I find the information? I'm not having much luck on a websearch but this looks to be the forum with the most hits on google so figured I'd try here. thanks for any help, KYle

Re: Fuel Mixture/ Suzuki FA50


This is the place for moped related questions.

Sometimes it may take a little time till someone notices you.

I have heard it said that the worn oil pump will allow oil to seep into the engine and make it smoke like the devil for the first couple of miles.

If there is enough oil in there it may not even run well or at all.

I have heard people say to remove the spark plug and kick the daylights out of it till it stops spitting oil out the spark plug hole.

I have not witnessed any of this except it does seem to smoke a lot.

If you wan't to premix simply remove the pump from the engine case and make a metal cover to attach in it's place using a good hi-temp orange RTV and some screws.

No need to remove the oil pump drive shaft, just let it spin, if you want to you can remove it.

Also you want to plug the oil inlet on the block, you can use a vacuum nipple plug.


Once you remove the oil pump you can use the oil tank as a gas tank by running a short fuel hose from the oil tank to the reserve port on the fuel tank.

That means the oil gauge is now your gas gauge!

This means that you wont have a reserve feature on the fuel valve and that port on the valve should be sealed so when you use the "Prime" position will prime your carb and not spill fuel all over the place from the old reserve port.

This is all done under the seat and behind the fuel valve so if you dont want to mess with that stuff just leave it like it is and ignore the oil tank.

Sorry, I do ramble on.

I think this link will allow you to view the other pages I gave archived for the FA50.



Re: Fuel Mixture/ Suzuki FA50

Also Kyle,

Do a little search on FA50 in this forum and performance tuning.

We have been talking alot lately about carb cleaning and little hiden parts that need cleaning on the FA50.

We have been able to get folks from a sickly 17 and 20MPH up to a rocking 35MPH.

I don't want to hash it out all over again.


Re: Fuel Mixture/ Suzuki FA50

thanks for the help rusty. I'll check out the other posts and see what I can find out. I can't say for sure whether the oil pump leaking is the source or not because it usually never went more than a mile or two on a trip anyways. thanks again, KYle

Re: Fuel Mixture/ Suzuki FA50

ok, removing the oil pump and related parts should be fairly simple, thanks for the diagram's. I'm also going to give the muffler some attention as this seems to be a bad spot, especially under the conditions of my rich running bike.

My follow-up question is what fuel/oil ratio should I use? thanks, KYle

Re: Fuel Mixture/ Suzuki FA50


I'm going to start with 32:1 because thats what I use on my Chinafire Bike conversions, and will move up to 40:1 later.

I'm sure a mix of 50:1 like most other mopeds use would be great for a 80's vintage FA50 when you consider the cast iron cylinder and nice roller bearings in em.


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