technical problem suzuki fa

I got a suzuki fa 50. I am fixing it up to use it as a daily driver. And It has a big time running problem that I just cannot figure out. The bike starts on the first kick. The engine runs and idles smooth however when your taking off from a stop it doesnt like any gas at all. From what I can gather it seems like its getting way too much air at idle. When you give it gas it stalls on the spot, the only way i can get it going is if I keep flicking the throttle rapidly (sometimes can take me 15 seconds to even start rolling on the thing.) Stock everything, plug chops come out light tan. Sounds about right at top speed 29 mph. The other problem I was getting was it right around 15 mph when you let off the gas. The engine speed doesnt drop it stays exactly the same as if you didnt let off the gas. The cylinder gaskets are new, so I know the air isnt leaking from the cylinder. I think its a carb problem now but I just need help in the right way. The only other thing that may have a slight impact on this is the plug is two numbers colder then the original one.


Re: technical problem suzuki fa

If you are getting 29mph and getting a light tan plug chop with a much colder plug from normal... IT'S TOO LEAN!!!

I'm going to guess that the main jet has some build up that gives the same effect as a smaller jet. I use a tiny drill that will fit the existing hole, twisting the drill with my fingers. This will remove the build up without altering the size of the jet. The other out is order a new jet from your local dealer.

Good luck!

Re: technical problem suzuki fa

29 MPH is pretty nice.

Does this stumbling condition improve once it's warmed up?

Try to adjust the idle mixture first, a little at a time like 1/4 turn till it idles best and see if it improved the off idle performance.

Main jet is 77.5 I would recommend a good carb cleaning.

Go here for an exploded view.

Remove and clean the emultion tube. Found under the main jet and may be difficult to remove since it may not have a nut head but be pressed inside the carb body under the main jet.

Some times an easy out will get it moving.


Re: technical problem suzuki fa

it runs the same if it idles for 10 minutes. I just went outside and adjusted the clip on the throttle body, put it all the way to lean...nothing all the way to rich....nothing. The main jet is clean as a whistle. I did not remove the emultion tube though. Thought I sprayed plenty of carb cleaner and compressed air through there. Infact I cleaned this carb three times. maybe I can try that tomorow

Re: technical problem suzuki fa

the other thing is the choke has no effect on anything, and I believe I put it back just the way it was. Not that I get how this choke is set up.

technical problem suzuki fa

hi im justin im 14 years old i read your comment it could be that your jet screw is to lean to fix this problem take a screw driver and tighten the jet screw all the way and then loosen it one and a half times this should work if not then if your moped does not have an air filter then hold 2 fingers over the hole where it is supposed to go and tapp if it runs good like that then you need to get a new air filter. also after the motor warms up make sure turn the choke off. i have the same moped a 1989 suzuki fa50 shuttle and 29 mph. is not bad but i did some tinkering with mine and got it to go 40.2 mph. also make sure that your gaping on your spark plug is good.

Good Luck!!!

Want to post in this forum? We'd love to have you join the discussion, but first:

Login or Create Account