Am I four-stroking? And what to do about it

Drew Cooper /
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Hello! New to the forums and mopeds in general so please bear with me.

About two months ago I got a 1983 Suzuki FA50 out of my grandfathers barn. It has been sitting for about 20 years. Changing the spark plug got it to start up, a new clone carb from Ebay ( https://www.ebay.com/itm/201950969646?ul_noapp=true ) got it to start up easily.

(I still have the original carburetor, but being new to this sort of thing, I figured for the price, a new carb was better than taking apart the original and potentially screwing it up.)

The guy who sold me the carburetor said it is completely stock including jets. It idles great and runs great until I open the throttle all the way. When I take it on a good stretch of road to test top speed, it tops at about 20.

BUT: when I let off the throttle just a little hair, it will inch its way up to 25. What gives?

Well I thought maybe the exhaust was clogged so I took it off and threw it in a charcoal grill for a while. I shook out some black flakes for a while, but maybe not as much as I expected, and I scraped out some carbon crap from the exhaust port on the engine. No luck though, but maybe I just didn't clean it well.

A look at Fred's Guide suggests it might be four stroking?

Specifically where he says "and the engine acts like it is choking, like it would like to go faster... and sometimes it WILL go faster if you close the throttle a little bit."

So, my questions are:

Is it my air filter? I bought the foam element brand new from treatland, but maybe I used too much oil... I soaked it and made sure to squeeze it out real good until nothing else came out. Also worth noting is I lost the slider bar that holds the box together on a bumpy driveway and have it held quite tightly with duct tape, but I don't think that would affect much.

Is it the carburetor/jetting? It's supposed to be stock, and I even asked the seller after I bought it about the jetting. He claims its completely stock.

There's a little clip that adjusts how deep the needle can go, should I try adjusting it? The service manual tells me I can make the mix richer or leaner this way. This shouldn't affect WOF, should it? Wouldn't that be the main jet?

What about adjusting the throttle? Is it possible that a wrong throttle adjustment at the handle would cause this issue?

Thank you all, I'm new to this so I'm not sure what to look for and I've tried scouring the internet for answers. It's frustrating because I'm sure that once I sort this issue out I'll finally have it up to stock speed, and I'm too stubborn to take it to a mechanic like my dad suggests.(edited)

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Subject Written By Posted
  Am I four-stroking? And what to do about itTopic by: Drew Cooper Drew Cooper 10/12/19 04:36PM
  Re: Am I four-stroking? And what to do about itRe: pat splat pat splat 10/12/19 04:44PM
  Re: Am I four-stroking? And what to do about itRe: Drew Cooper Drew Cooper 10/12/19 04:48PM
  Re: Am I four-stroking? And what to do about itRe: P D P D 10/12/19 05:32PM
  Re: Am I four-stroking? And what to do about itRe: Drew Cooper Drew Cooper 10/12/19 06:02PM
  Re: Am I four-stroking? And what to do about itRe: Daniel '' Daniel '' 10/12/19 11:10PM
  Re: Am I four-stroking? And what to do about itRe: Don Ohio Don Ohio 10/13/19 02:15PM
  Re: Am I four-stroking? And what to do about itRe: Drew Cooper Drew Cooper 10/13/19 03:19PM
  Re: Am I four-stroking? And what to do about itRe: Don Ohio Don Ohio 10/13/19 08:16PM
  Re: Am I four-stroking? And what to do about itRe: Jeffrey Strichart Jeffrey Strichart 10/13/19 10:03PM
  Re: Am I four-stroking? And what to do about itRe: Don Ohio Don Ohio 10/13/19 11:28PM
  Re: Am I four-stroking? And what to do about itRe: Drew Cooper Drew Cooper 10/13/19 10:03PM
  Re: Am I four-stroking? And what to do about itRe: Drew Cooper Drew Cooper 10/13/19 10:16PM
  Re: Am I four-stroking? And what to do about itRe: Jeffrey Strichart Jeffrey Strichart 10/13/19 10:54PM
  Re: Am I four-stroking? And what to do about itRe: Drew Cooper Drew Cooper 10/14/19 09:46AM
  Re: Am I four-stroking? And what to do about itRe: Jeffrey Strichart Jeffrey Strichart 10/14/19 10:10AM
  Re: Am I four-stroking? And what to do about itRe: P D P D 10/14/19 11:03AM
  Re: Am I four-stroking? And what to do about itRe: Drew Cooper Drew Cooper 10/14/19 11:27AM
  Re: Am I four-stroking? And what to do about itRe: Drew Cooper Drew Cooper 10/14/19 11:33AM
  Re: Am I four-stroking? And what to do about itRe: Drew Cooper Drew Cooper 10/14/19 05:09PM
  Re: Am I four-stroking? And what to do about itRe: P D P D 10/14/19 05:44PM
  Re: Am I four-stroking? And what to do about itRe: Jeffrey Strichart Jeffrey Strichart 10/16/19 01:39AM
  Re: Am I four-stroking? And what to do about itRe: Drew Cooper Drew Cooper 10/15/19 03:24PM
  Re: Am I four-stroking? And what to do about itRe: Jeffrey Strichart Jeffrey Strichart 10/16/19 01:43AM
  Re: Am I four-stroking? And what to do about itRe: Drew Cooper Drew Cooper 10/15/19 10:38PM
  Re: Am I four-stroking? And what to do about itRe: P D P D 10/16/19 09:27AM
  Re: Am I four-stroking? And what to do about itRe: Drew Cooper Drew Cooper 10/17/19 05:16PM
  Re: Am I four-stroking? And what to do about itRe: P D P D 10/17/19 06:38PM
  Re: Am I four-stroking? And what to do about itRe: ken gilbert ken gilbert 10/18/19 11:24AM
  Re: Am I four-stroking? And what to do about itRe: Rebel Moby Rebel Moby 10/18/19 03:16PM
  Re: Am I four-stroking? And what to do about itRe: ken gilbert ken gilbert 10/21/19 06:35AM

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