Suzuki fa50 bogs down at full throttle.

mark patterson /

I just picked up a suzuki fa50 1983 that had been sitting for a long time. I got the carb cleaned out, and put back together. I got this baby running, but I cant manage to make it above 20 mph. When ever I give it full throttle it bogs down and wants to die till I let off the throttle. Runs perfectly fine at the first 3/4 of throttle and idles steady. Ive cleaned the spark plug and checked that the muffler wasnt clogged. Any Ideas? Im guessing it has something to do with the carb. Should I adjust the needle level? Float level? Thanks. Also while the moped is running and on its stand the back wheel spins is this normal?

Re: Suzuki fa50 bogs down at full throttle.

Fuel flow, air leaks, dirty carb. The bike won't do a whole lot more than 24-25 even running well.

Re: Suzuki fa50 bogs down at full throttle.

What is the compression ?

My FA50 does 28 - 30 MPH , even with lower compression and a single ring in a worn cylinder .

And , yes , it's typical for the rear wheel to want to turn while on the stand . It should be able to idle with the rear brake applied or the wheels resting on the ground .

Re: Suzuki fa50 bogs down at full throttle.

mark patterson /

I havent tested the compression but I know its good. I was able to get it to go full throttle when I partially cover the air inlet. So My next step is to check the gas lines, and maybe adjust the carb needle?

Re: Suzuki fa50 bogs down at full throttle.

Well if you don't have the air box on then that is your problem.

Re: Suzuki fa50 bogs down at full throttle.

> DPC Ryan Wrote:

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> Well if you don't have the air box on then that is your problem.

Agreed ^ .

My bike ran like crap without an air filter , let alone no air box .

Re: Suzuki fa50 bogs down at full throttle.

mark patterson /

I put the airbox back on and to my surprise it does run better. But Im still getting the boggingwhen I got to about 20. I think im going to try adjusting the jet needle to allow a richer flow? Any advice. Thanks.

Re: Suzuki fa50 bogs down at full throttle.

Do you have the carb set to factory specs according to the manual ?

Re: Suzuki fa50 bogs down at full throttle.

The needle does not affect full throttle operation, it's not a weed eater. If the bike is stock it should run as stock. There is something broken, worn, or leaking. Check for fuel flow and air leaks.

Re: Suzuki fa50 bogs down at full throttle.

What is the condition of the foam filter which resides inside that airbox?

Re: Suzuki fa50 bogs down at full throttle.

> DPC Ryan Wrote:

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> The needle does not affect full throttle operation,

That's right , but , it will affect how it gets there .

Re: Suzuki fa50 bogs down at full throttle.

> P D Wrote:

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> > DPC Ryan Wrote:

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> > The needle does not affect full throttle operation,

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> That's right , but , it will affect how it gets there .

But he said it runs fine until he goes full throttle, moving on.

Re: Suzuki fa50 bogs down at full throttle.

> DPC Ryan Wrote:

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> > P D Wrote:

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

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> > > DPC Ryan Wrote:

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> >

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

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> > > The needle does not affect full throttle operation,

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> >

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> > That's right , but , it will affect how it gets there .

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> But he said it runs fine until he goes full throttle, moving on.

True . He's likely going directly to full throttle . I do that a lot and it does take a bit for the motor to 'catch up ' , so to speak .

I've tried different settings and no filter or less filter . The results were poor , at best .

If he still has trouble after stock settings , then I'd start looking 'deeper' .

Re: Suzuki fa50 bogs down at full throttle.

mark patterson /

Yes the needle is set to stock currently and So is the air valve 1 and 3/4 turn out.

Re: Suzuki fa50 bogs down at full throttle.

mark patterson /

When I got it and opened the air box the filter literally crumbled haha. I made my own out of a FILTRETE cut to fit air filter sheet from lowes for 6 dollars. https://www.lowes.com/pd/Filtrete-Cut-to-Fit-Common-20-in-x-30-in-x-1-in-Actual-20-in-x-30-in-x-0-25-in-Washable-Adjustable-Air-Filter/50124672 . I didnt feel like paying 20 dollars for a freaking piece of foam.(edited)

Re: Suzuki fa50 bogs down at full throttle.

I don't blame you for saving money .

I'm not sure the material you're using offers enough resistance .

I use 1" thick open cell foam and have good results . I do soak it with oil and squeeze out the excess oil until the filter has a slight crackle or faint popping noise when squeezed/pumped .

Re: Suzuki fa50 bogs down at full throttle.

> mark patterson Wrote:

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> ...When I got it and opened the air box the filter literally crumbled...

> I made my own out of a FILTRETE cut to fit air filter sheet ...

After trying many types of foam I have found that my Yamaha MJ50 will only run using an OEM Yamaha piece of $20 foam. Good luck.

Re: Suzuki fa50 bogs down at full throttle.

mark patterson /

Ive tinkered a little more with it and now it seems that I can get to full throttle but I cant stay there, it will bog down then try to catch up. Also could this have anything to do with a bad battery? Currently the battery doesnt have the charge as its like 30 years old. Ive ordered a replacement. Should be arriving soon.

Re: Suzuki fa50 bogs down at full throttle.

No not the battery., for the 4th time, check fuel flow. Check gas cap venting, fuel filter, petcock, float needle.

Re: Suzuki fa50 bogs down at full throttle.

mark patterson /

I know for sure the fuel flow is good when the petcock is set to prime so when I run it I just leave it on prime to bypass any problems with the petcock. Gas cap venting I checked as well. The float needle ehh? When I had taken apart the carb and I took out the float needle the float needle valve was stuck and I couldnt manage to get it out maybe the old rubber? So I just made sure to clean it well and check that it wasnt clogged and gas could flow through which it was. But the float level could be causing this?? Also I didnt check for air leaks as when I restrict the air flow at the air inlet on the carb it will reach full throttle it seems.(edited)

Re: Suzuki fa50 bogs down at full throttle.

mark patterson /

Do you know of a good replacement carb under 50 dollars for this? Ive seen the 20 dollars ones on amazon but they got bad reviews and it sounds like they are hit and miss. I dont wanna spend 170 for a new oem carb.

Re: Suzuki fa50 bogs down at full throttle.

See if you can get just a float needle. Float level will affect your mixture and you sound lean.

Re: Suzuki fa50 bogs down at full throttle.

Suzuki doesn't offer just the needle . They offer the needle and seat set for about 33 bucks .

The OEM Suzuki needle has a metal tip . As long as that tip is not deformed , it should be good . The OP hasn't mentioned any type of fuel leakage , so , I suspect the needle and seat are copacetic . I would leave them alone .

Do check float level :

Re: Suzuki fa50 bogs down at full throttle.

3 things. Float seat o ring, float bowl gasket or float level.

Re: Suzuki fa50 bogs down at full throttle.

Well with a metal tip then unless the needle is sticking or the float isn't floating I would point toward a partially plugged main jet.

Re: Suzuki fa50 bogs down at full throttle.

mark patterson /

Well I decided to just buy a new carb off ebay so I dont have to fuss with all this because I am a novice when it comes to carburetors and I dont feel like getting carb cleaner in my eye again ;). Hopefully The one I ordered is good quality. Ill update if it fixes the issue. Thanks all for the replies.

Re: Suzuki fa50 bogs down at full throttle.

The one you ordered is likely to be cast rough and not jetted at all for your bike. Add to that you will need to find out what kind of jet will even fit in it. You are never, ever better off getting a "new" clone carb.

Re: Suzuki fa50 bogs down at full throttle.

Say no to clones

Re: Suzuki fa50 bogs down at full throttle.

Ain't nothin' like the real thing , baby . ;)

Re: Suzuki fa50 bogs down at full throttle.

mark patterson /

I got to see for myself. We shall see how it goes. Maybe I will be one of the lucky ones haha.

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