Suzuki FA50 mystery problem??

Hi, I just signed up today. I have a Puch Magnum XK and Suzuki Fa50. Ok, My FA50 I just recently had donated to me with 3000 mi on it, starts right up and runs but when you give it gas it just sorta revs weakly but doesnt go anywhere. It doesnt sound like its reving real strong at all, and if you lift the rear wheel up and open the throttle it will spin the wheel kinda fast and rev harder but as soon as you get it back on the ground it jus goes blaaaaaa and wont move an inch, even with the throttle wide open. And I'm only 150lbs so its not that haha. I've had the tranny case apart, checked it all out and visually there is plenty of friction surface left on the clutch and hardly any wear on anything. I'm wondereing if its something with the motor not the clutch or drive train. I mean it sounds really flat and low on power. Electrical maybe? Any help at all is great.

Re: Suzuki FA50 mystery problem??

i would check to make sure that the exhaust is not clogged. take the mufler off and try to run it that way. Dont do it for too long maybe 3 minutes. if you do it too long you could seize the engine. so take the muffler off try to run the moped like that, if it helps that mean you probably have a clogged muffler otherwise it might be your fuel mixture. let me know if its the exhaust?

Re: Suzuki FA50 mystery problem??

Ben Elsewhere /

definitely reference Fred's and adjust your carb accordingly, that could be the problem, if not, I totally agree that the muffler might be coked up.

Re: Suzuki FA50 mystery problem??

Make sure the oil the the transmission is motorcycle crankcase oil ie meant to be used with wet clutches. If it is regular motor oil with additives, the clutch won't operate properly. Just a thought.

Re: Suzuki FA50 mystery problem??

Matthew Westberg /

If it sounds/feels like it has no power it might also be a timing issue.


ok it came with automatic transmission fluid in it, so not having a service manual i put tranny fluid back in the gearbox. But would that cause the problem? I mean it is alot thinner than gear oil. Ill take the exhaust off, check that and adjust the carb. Thanks, ill let you guys know

ok checked a few things

i took the carb apart cleaned it and set the idle, still it bogs down the same as before. The more throttle you give it the worse it sounds. I took off the pipe and it ran even crappier, loud as sin tho. I drained the automatic tranny fluid. I think I have some 75w 90 gear oil. Would that work in the gear box? Ill check the timing but I have no idea how on this thing, anybody know? Damn its frustrating

Re: Suzuki FA50 mystery problem??

Why not get a small engine shop to give it a compression check. As for the transmission, you should put in 20w40 oil. I use Yamalube, but I think I've read that WalMart sells it too. It should be the kind without the friction fighting additives ie. for wet clutches. Have you looked at the large gear that is on the shaft that the rear wheel is on? The last gear in the drive-train. I've seen a couple that are completely stripped out or on their way to that condition. Wouldn't hurt to give a second look to see if the gear teeth are meshing completely and properly. We'll get to the bottom of this..eventually!


so yeaa I checked the exhaust port in the cylinder, totally blocked except for an opening less than 1/4 inch in diameter. Thats why it sounded like it was suffocating when I gave it gas, and why the plug was rich. I cleaned that all out nice and good. I dont want to run it with no gear oil so Ill pick up some of the stuff you suggested tommorow and then give it a try again. Hopefully that should do it but I have a feeling there are a few more probs with it. I have a compression tester also. Whats good 80 psi? And the all the teeth on all the gears show virtually zero wear. Should be a sweet runnin machine at the end of this. Ill keep updating, thanks for all the help

Re: Suzuki FA50 mystery problem??

yea, my fa50's gears in thegearbox have 0 wear to...and mine is from 86' ....i think the gearbox gears are the highest quality thing in the mopeds.

Re: update...

I think 80 is marginal. I seem to recall someone saying 110 or over is desirable, but I could be wrong.

Re: update...

Ok its making 126psi. Thats good. I also filled it up with the right oil. I decarbonized the whole engine and it now moves and gets up to about 15 mph but if I open the throttle it bogs and stumbles. Does my fa50 have a CDI ignition, cuz that would rule out timing probs right? I'm almost certain its the carb, either too much or not enough fuel. Anyone know anything about the auto fuel switch, is it vacuum operated? I've also cleaned the carb out thoroughly, but maybe theres just one little spec stuck up in there.

Re: Suzuki FA50 mystery problem??

Timmy Southpark /

yeah its a cdi, and i would mess with that last. Have you checked the air cleaner? maybe it needs to be changed or cleaned, i know puch mopeds run like crap when there isnt an air cleaner. also, clean the carb real well, then maybe a plug chop???

Re: update...

I had to clean mine three times before it ran right. I read awhile back that FA50s are particularly sensitive to dirty carbs. The fuel pump in the petcock assembly is vacuum operated. You might put an in-line fuel filter on at some time after you get it cleaned up. Did you check for a vacuum leak at the carb? Use search function if you aren't sure how to do it.

thanks guys..

Ok I'm gunna mess with it more this weekend. I'm sure It'll be runnin sweet soon enuff. Then I'll have 2 running mopeds so my buddies can come cruisin haha. Thanks!

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