suzuki fa50 frustration


i have a 83 suzuki fa50, its got 1013 miles on it, has good spark ( new plug ) and ive cleaned the carb numerous times, all the carb parts are good screw everything not worn at all, im frustrated at why this wont go more then 15mph, ive played with the screws 2 on the carb and the best i can get its barely touchign 15mph ive been at this on and off for a year, anyone got ne ideas

Re: suzuki fa50 frustration

there's a bunch of things that could limit speed .. ignition timing, a compression leak, a vacuum leak .. a clogged muffler or exhaust port .. dragging brakes.. a choke plate or throttle slide that's got a problem and is partially closed all the time.. and lots of others ..

take a whole day out and give it a complete going over and don't neglect anything. Read FREDs GUIDE for a pretty good list of things to check and some tips.

Re: suzuki fa50 frustration

what if i just run w/o the muffler , other then the complete and utter loss of back pressure , what r the downsides of that, would i loss alot of power. ive ran through freds guide over and over no change my ignition timing its a lil bit advanced maybe its 20 btdc i should do a compression test, its only got 1k miles parts can be worn that bad, brakes arent draggin cus i have to pull the handle 1/2 the way to get it to being to engage, my hoses have no holes ,vacuum lines pull a vaccuum , cdi ignition no breaker points to deal with i suppose i could check for carbon build up, if i took the head off would i need a new gasket

Re: suzuki fa50 frustration

there's no harm (except to your eardrums) running no muffler to test that .. I and a few other people around here have done it.

What should happen is top speed increases since exhaust exit is much improved at top RPM. However, you lose lots of fresh mixture out the exhaust and at lower RPMs, ow-speed power will suffer badly.

My top speed went from 30 to about 37 MPH without the muffler.


yeah.. do a compression test. You could have any sorta problem on the top end .. damaged rings or rings stuck in their grooves.. a holed piston .. a warped head .. who knows.

Dont be shy about pulling the head for the sake of a freakin head gasket. New ones are easy to make from sheet aluminum or copper.


You've checked so many things that it might be time to get serious and check crankcase compression too .. might have a leaking mainseal.

A leak there will show oil residues on the outside of the engine near the main bearings. Sprinkle some baby powder around the bearings. If it turns dark oil being blown out the seal is making it dark.

The crankcase should hold about 7PSI for at least a few minutes.

Seal all openings and use a small hand pump. Seals might blow (be ruined)) with more than about 10 PSI of pressure.


A lot can happen in 1,000 miles or even in 10 miles .. Like running without lubrication can do amazing things pretty quickly.

Pull that head and look-see whats up in there.

Re: suzuki fa50 frustration

ill check that out, when i got it there was no oil in the tranny ( i think it leaked ou from sitting, a prob that used to occur) but there was in the engine oil tank, ill pull the head and check ne idea what makes a good replacement for that filter, / air box all together, i lost the air box and filter need ne kinda of replacement

Re: suzuki fa50 frustration

Are you running with no air box?

That may be your problem, this will cause you to run way lean and you will only achive about half throttle.

You don't clearly state your symptoms.

Does it bogg or cut out and you have to close the throttle?

Or does it just run out of power to gain speed at WOT?


Re: suzuki fa50 frustration

it bogs down at wot , like if its on the stand and i bring it to wot it bogs down to a point where i have to back it off to keep it from stalling , i have no air box but its still running rich, while it runs fuel is misting out the opening of the carb ( where the air enters)

Re: suzuki fa50 frustration

i also thinks its running rich because if i spray , something like starting fluid in , it bogs down, and may stall depending on the amount sprayed in

Re: suzuki fa50 frustration

ne ideas

Re: suzuki fa50 frustration

you want more guesses or are you wondering how to do a particular thing?

Piston ported induction 2-stroke engines (those without reed valve or rotary induction) normally spray a bit of fuel out of the intake at LOW rpms.

Those with reeds do not, unless the reed petals or reed block has a problem.

Spraying starting Fluid may or may not kinda foul the plug .. it alone is not a positive indication that the engine's running rich.

Re: suzuki fa50 frustration

This is a reed induction motor so perhaps your reeds or reed block are damaged.

In my opinion if it boggs at wot it's not enough fuel not too rich.

Try running with the choke on and see what happens.

You really need a air box.

I never saw a ped that would run properly without one unless it has bee jetted up.


Re: suzuki fa50 frustration

is there some type of way i can put another one together , like a lawnmoer one with some tubing or something, cus therel ike 30$ for a new airbox, also when i hold my hand over the opening on the carb the engine revs up

Re: suzuki fa50 frustration

those mopeds have an inherent problem with oil that endlessly drips slowly into the block when the moped is not being driven. you could have a ton of it in there. it's happened to me. you may have a bunch of other things wrong too. it needs compression, spark, fuel, and to breathe in and out.

Re: suzuki fa50 frustration

ya i filled it up with oil at one point and all teh oil disapeared and didnt leak out, wouldnt the oil burn up tho, i mad an adjustment ot the part on teh carb where the cable clips in and leaned it out, according to the manual , i leaned it out ot the extreme, and now it wont run that long ill richen it up a lil bit, i have compression spark and fuel , definately the ability to breathe in but i dont kno aobut out

Re: suzuki fa50 frustration

Aaron in Bellingham /

I have the same problem. I have 2 that I'm fixing up today and I plan on taking off the cylinder jugs and cleaning the possible carbon buildup.

Re: suzuki fa50 frustration

ed james, Is there a way to solve that problem of oil dripping while not in use? Mine seems to burn to much oil the first couple minutes when I start it.

Re: suzuki fa50 frustration

now that i noticed it i am losing oil pretty fast i went through an 8th tank in like a day

Re: suzuki fa50 frustration

I suspect the oil seeping problem must be on high mileage worn out pumps.

I have not had this problem.

It starts right up and is ready to go even after being ignored for a week.

I hate to suggest this because if you forget to turn it on you will kill the engine.

How about an in-line valve to turn off the oil supply.

The prefered method is to remove the oil pump and premix the fuel. The oil tank can be your reserve fuel tank.


Re: suzuki fa50 frustration

Thanks Rusty, mines not that bad, just the first couple minutes until I take the choke all the way off.

Re: suzuki fa50 frustration

Is there any way to tell if the oil pump is going bad besides just noticing that the oil level isn't changing. Just curious. Eventually it would destroy the engine right?

Re: suzuki fa50 frustration


There is a procedure for verifying the flow.

It should consume from .97 to 1.14 ml in 6 minutes at 2000 RPM.

You can use a large syringe pluged into the oil pump with a hose.

Remove the plunger from the syringe and plug it into the pump using a small hose, hold it up with the tip down fill it with oil and bleed out the bubbles if any from the oil hose and pump.

Run the test and see how much oil it used.

Note the oil pump should always be bleed when the hoses have been disconnected or the tank run dry.

There is a small philips head bleed screw on the front of the pump.

If this is not clear I can scan the page from the manual.


Re: suzuki fa50 frustration

maybe my clutch is slipping? what r some symptoms of that , i open the moped to full throttle and lock up the rear wheel and it doesnt stall,what r some moresymptoms of a slipping clutch

Re: suzuki fa50 frustration

I quote from the service manual.

"Clutch "Lock-up" inspection"

Perform this inspection to determine if the clutch is engaging fully and not slipping.

1. Warm the engine to normal operation temperature.

2. Connect a electrical tachometer to the engine.

3. Apply the rear brake as firm as possible.

4. Briefly open the throttle fully and note the maximum engine RPM sustained during the test.

Caution: do not apply full power for more than 10 seconds or damage to the clutch or engine may occur.

Lock-up RPM

Std = 3500 rpm + - 300 rpm.

It's not supposed to "stall" just have a limited amount of slip which is expected but not more than that.

If it feels healthy it probabily it healthy.



Thanks, for all the help Rusty! My fa50 is running great! I've been doing 30 to 32 mph. I replaced both bearings in the transmission case. Now, its sounding good. The only thing I can't figure out moped won't start without about 6 kicks or I can get it to start on the first kick if the choke is out and then it will die in about 3 sec. and it will do this repeatedly? However, once I ride my moped it will start on the first kick (without the choke) no matter what. It just seems to have trouble once it sits over night for some reason? I was wondering if you by chance have an extra ignition with a key that you would want to sell? Thanks again!


Re: fa50


Glad to hear things are looking up for your FA50, you should be good for many miled of riding now.

The ignition and key is hard to find unless you feel like paying $35 to, I don't even have one for me.

Regarding the hard start problem, try adjusting the mixture screw.

Adjust it so it starts easy, run it and shut it down over night.

Next day do it all over again.

I had the same problem and the adjustment helps.

I just bought a FZ50 engine case and internal parts.

It's a 2.5 HP with a 2 speed auto trans which I hope to transplant into my FA50 frame.


Re: fa50

my engine seems fine but the bike is slow as all sin im lucky if i get over 10mph

Re: fa50

could it be the tranny?

Re: fa50

Rusty, Thanks for all the fa50 help! Would you be willing to scan the whole manual for $?

Re: fa50


Does it rev up and barely move (trans), or does it just resist acceleration (carb or ignition)?

Have you cleaned the carb and the spark plug?


I have been scanning and posting pages which are available for you to view.


Re: fa50

ill start it up , and ill open the throttle it and it will either a) bog down and stall b) gain power and midrange die out and stall or c) gain power and stay at the same midrange amount even at full throttle

ive played with the idle and right now its at (B) ive cleaned the carb 3 times no jokes, got a new rtv made gasket and i got a new plug , i did a plug chop and the plug was a lil bit darker then tan brown , like a tanish grey , but not wet. when i open the throttle its like the air kills it , but when i put my hand open the carb inlet at idle it revs up, making me think its too lean, but i restricted the carb a lil to simulate an air filter, and no gain in power,

i can full throttle the bike and with my feet on the ground it will sit

im going to clean the reed valve out today

if i ride it and full throttle it i cant get over 10, if i slow bring up the throttle i cant get over 10

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