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| | | | | Motorized Bicycle General Discussion Topics on bicycle engine kits, help articles, repair and modifications for your motorized bicycles | Question about 2 stroke running. Discussion at Motorized Bicycle Engine Kit Forum in the Motorized Bicycle General Discussion forum. In browsing through other threads I commonly read people talking about their 2 stroke acting as a 4 stroke while ...  | 
05-30-2008, 08:28 PM
| | Senior Motorized Bicycle Builder | | Join Date: May 2008 Location: Long Island, New York
Posts: 80
| | Question about 2 stroke running. In browsing through other threads I commonly read people talking about their 2 stroke acting as a 4 stroke while cruising and 2 stroke when accelerating. Ok...what does this mean? If it's a 2 stroke, how does this thing 4 stroke? The SLIGHTEST Idea I can come up with is that this pertains to a different in pitch from the engine because It sounds more of a pop pop pop when cruising but more of a brrrrrrrrrr when accelerating, but I can be way off. Any insight? | 
05-31-2008, 07:11 AM
|  | MODERATOR | | Join Date: Jan 2008 Location: Ashtabula county, Ohio
Posts: 4,065
| | Re: Question about 2 stroke running. That was probably me talking about the 2 stroke/4 stroke thing.
What happens is the engine not under load has too rich a mixture and fires every other cycle, like a four stroke engine. Most modern 2 strokes will run in a 2 stroke all the time, but our ancient piston ported engines will (when properly set up) break between a two cycle and a four cycle.
When just right, these engine break between a two stroke and a four stroke as they run in cruise mode, the slightest extra pull causing the engine to break into a full rich two stroke cycle.
__________________ If it ain't broke, and you mess with it long enough, it will be. | 
05-31-2008, 07:37 PM
| | Banned | | Join Date: Mar 2008
Posts: 140
| | Re: Question about 2 stroke running. 4 stroking a two stroke means the mixture is so rich that it fires 1/2 as often as it should. 4 stroking is not recommended because it'll foul the plug and may cause rings to stick plus it will never allow engine to hit its normal operating temperature. | 
05-31-2008, 07:49 PM
|  | MODERATOR | | Join Date: Jan 2008 Location: Ashtabula county, Ohio
Posts: 4,065
| | Re: Question about 2 stroke running. Yes, but when set up right, these engines do four stroke when not loaded.
I changed my carb settings a dozen times an every time I got it to run in a two stroke across the range, there was less power and the engine ran hot.
__________________ If it ain't broke, and you mess with it long enough, it will be. | 
05-31-2008, 08:45 PM
|  | Master Motorized Bicycle Builder | | Join Date: Jan 2008 Location: north carolina
Posts: 3,747
| | Re: Question about 2 stroke running. Has two modes but I just ignore the one that sounds like its about to explode. | 
06-01-2008, 01:53 AM
| | Senior Motorized Bicycle Builder | | Join Date: May 2008 Location: Long Island, New York
Posts: 80
| | Re: Question about 2 stroke running. Seems like mine is running well then. I had to adjust the carb clip because it was going through fuel faster than it should, but now it runs great and the plug is a light gray color with oily carbon everywhere else...which I assume is good and normal for 32:1 mix. | 
06-01-2008, 08:01 AM
|  | MODERATOR | | Join Date: Jan 2008 Location: Ashtabula county, Ohio
Posts: 4,065
| | Re: Question about 2 stroke running. Light grey is a little lean for a two stroke engine...should be a chocolate brown.
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