1980 Suzuki FA50 Stock Speed Issues

Picked up this 1980. Runs great and got up to speed which was 27-29 mph with me on it @ 250 lbs. There was couple issues; one being problem with fuel leaking from gauge area, and the carb was leaking some fuel as well.

So took apart carb. Cleaned it, put it all back together. Took the gauges off of the tanks and capped them off where the gauges were. Have not touched any of the oil whatsoever on this thing. It has the proper 500 mil and it was fresh oil. So left it alone.

Now that this was all done the bike will only hit 19-20 mph. It idles great. It starts first kick even after week sitting and extreme cold weather. I mean the bike just starts up runs great. Doesn’t cut out nothin. Any ideas on what this can be? Going from stock speed to losing 8-9 mph just with carb pulled off and cleaned, and the only other thing changed was plugging the gas tank where the gauge use to be.

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Re: 1980 Suzuki FA50 Stock Speed Issues

By gauge , do you mean petcock ? If so , are you running fuel line directly from the tank to the carb ?

And , provided you did the carb correctly , check that the exhaust is clear .

How many miles on the bike ?

Re: 1980 Suzuki FA50 Stock Speed Issues

Jack Rutherford /

In the Wiki, they mention that 500ml is too much oil and recommend 300ml and that 500ml will slow you down. Also Suzuki may have jetted these rich and by cleaning the carb, you may have gotten it back to its rich state which would cause you to lose speed. Did you notice that tiny opening in the intake when you removed the carb? Check out the ports in the cylinder as well. I guess Suzuki was going for fuel economy with this model.

Re: 1980 Suzuki FA50 Stock Speed Issues

I run 500ml and regularly see 30+ MPH on my almost stock FA50 . And , that's on a very worn top end .

The difference I found was the oil . I tried many different oils from single and multi weights ; dino and synthetic and now I run 15w40 diesel , ONLY .

Maybe I should try 300ml . I might hit 40 ? JK . ;)

Re: 1980 Suzuki FA50 Stock Speed Issues

> P D Wrote:

> -------------------------------------------------------

> By gauge , do you mean petcock ? If so , are you running fuel line

> directly from the tank to the carb ?

>

> And , provided you did the carb correctly , check that the exhaust is

> clear .

>

> How many miles on the bike ?

By gauge meaning fuel level gauge that is located on side of the tank. Petcock still there and operable. 1100 miles. Exhaust is clear.

Re: 1980 Suzuki FA50 Stock Speed Issues

> Jack Rutherford Wrote:

> -------------------------------------------------------

> In the Wiki, they mention that 500ml is too much oil and recommend 300ml

> and that 500ml will slow you down. Also Suzuki may have jetted these

> rich and by cleaning the carb, you may have gotten it back to its rich

> state which would cause you to lose speed. Did you notice that tiny

> opening in the intake when you removed the carb? Check out the ports in

> the cylinder as well. I guess Suzuki was going for fuel economy with

> this model.

The oil and levels I think are fine for now but thanks for info. Speed was not issue before carb was off. So you’re saying that the stock adjustments to the carb in the manual are not right to setting it up to run at stock speeds? Stating those adjustments are to rich thusly causing speed issue?

Re: 1980 Suzuki FA50 Stock Speed Issues

Ah yes . The '80 has the fuel level gauge . My '84 does not .

As for the carb adjustments , my '84 wouldn't run right with any other adjustments .

I set it to factory spec and it runs just fine .

Re: 1980 Suzuki FA50 Stock Speed Issues

Jack Rutherford /

I don’t have direct experience with an Fa50. I do however recall that cleaning the carb on my urban express made it four stroke worse than before and I lost a couple few mph. I would think that Honda, Suzuki, etc., erred on the side of setting these up to run rich - what do they say - better to foul a plug than rebuild a top end. So cleaning your carb may have resulted in it running rich again and may account for some top speed loss. Or it could be something else. Run it once without the air filter and see how it responds.

Re: 1980 Suzuki FA50 Stock Speed Issues

^yeah pull the filter n try again, no air filter means leaner furl mixture, take a peek down the throat to make sure its opening all the way. is the choke off?

Re: 1980 Suzuki FA50 Stock Speed Issues

update:

pulled off the filter outer cover, ran it, gained 2 mph, then pulled over removed the plastic insert that sits on top of the filter material, and got it up to 25-26 MPH ish which is almost close to what it was doing before carb cleaning.. thoughts?

It will not run at all without the air filter, will idle but throttle will bog it down killing it. However filter cover off, and plastic insert that sits on top of "foam or cottonish" material it almost gets back to where it was.

Also choking at startup works as should. however trying to throttle or run it with choke on results in bogging it down to where it will die.(edited)

Re: 1980 Suzuki FA50 Stock Speed Issues

i dont have an fa50 but sounds pretty sensitive, looking at the diagram order goes plastic piece, foam n then cap.

sounds dumb but when u cleaned carb did u drill the jet? does the carb still leak?

Re: 1980 Suzuki FA50 Stock Speed Issues

no leaks at all. idles great, revs great, everything seems perfect except for the top speed. i will try reversing the order and see how it runs with plasitc on the inside closest to carb, then material, then cap...that is how it was...maybe is wrong??! idk lol

Re: 1980 Suzuki FA50 Stock Speed Issues

> pat splat Wrote:

> -------------------------------------------------------

> i dont have an fa50 but sounds pretty sensitive, looking at the diagram

> order goes plastic piece, foam n then cap.

>

> sounds dumb but when u cleaned carb did u drill the jet? does the carb

> still leak?

well good sir...i think that just solved the problem. I have looked at that damn manual hundred times, and never noticed the filter components being in the wrong order. I am pretty certain it solved the issue. It ran great before carb clean with filter set up in that manner. now that carb was cleaned, etc it obviously did not like the filter arrangement. think was starving for air...but not really sure why would run great with filter arranged in that manner previous to the clean?

Re: 1980 Suzuki FA50 Stock Speed Issues

now to clean the foam just squeeze and hold up to nose. its the gas man whatcha

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