Engine Sprocket problem!?

C

cruiserdude

New Member
I recently bought a schwinn w/50cc engine..the engine works fine, EXCEPT...when the engine is cold...it coughs bad before the engine starts, I pedal real fast til about 10mph, let go of the clutch, it coughs like its about to stop,,,but pulling the throttle gives it the small boost it needs til the Rpms are normal. When the engine is warm on start , it starts a bit better on only 5mph of peddling. When the Engine is still a bit cold, i come to stop before turning, the engine stops completely,,, if it is warm, it will stay on for a little while but still stop, not giving me enough time to turn. Whats up with my engine, i hate the cough because it pushes the bike and sounds like a grinding sound. Ive tried bringing the throttle nut down a bit but all it did was give me more throttle space.
 
Sprocket problem?

So you have gone through the basics: lots of clean fresh fuel mix supplied to the carb? No air leaks? Is the engine broken in?

Otherwise does it idle OK?

What spark plug? What does it look like?
 
I dont know how to check for air leaks, but nothing is leaking liquid. No the engine has not passed its break in period. What do you mean Idle? If you mean does the engine stay on while your on a stop sign, then NO, it might stay on for some seconds if the engine is WARM , but if its cold then it wont stay on. The Spark plug is a regular spark plug.
 
Are you using the choke? Are you "tickling" the carb"? The idle..turn in the idle screw until it idles. It's the screw with the spring on it, right beside the "tickler" button on the carb.
 
cruiserdude said:
I dont know how to check for air leaks, but nothing is leaking liquid. No the engine has not passed its break in period. What do you mean Idle? If you mean does the engine stay on while your on a stop sign, then NO, it might stay on for some seconds if the engine is WARM , but if its cold then it wont stay on. The Spark plug is a regular spark plug.
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You can check for intake air leaks best if the beast will actually idle (check with propane, WD-40, water, etc on the suspect leaking gasket or seal). You've go to get the beast to idle. Have you tried the idle screw? How soon before you open the choke up? In fact, what happens when you use the choke?

Is the head appropriately torqued to ~ 14 ft lbs?

So the plug is the supplied China one? Throw that sucker on the neighbor's lawn and get and NGK. B5HS would be a starting point.
 
cruiserdude said:
I dont know how to check for air leaks, but nothing is leaking liquid. No the engine has not passed its break in period. What do you mean Idle? If you mean does the engine stay on while your on a stop sign, then NO, it might stay on for some seconds if the engine is WARM , but if its cold then it wont stay on. The Spark plug is a regular spark plug.
Click to expand...

I had the same problem at a stop and it ended up being a loose exhaust cap, not enough back pressure. You may also want to try tightening the clutch cable just a little bit.
 
toytime said:
Are you using the choke? Are you "tickling" the carb"? The idle..turn in the idle screw until it idles. It's the screw with the spring on it, right beside the "tickler" button on the carb.
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Toytime your the best!, i didnt know what that screw was at first, but all this time it was too loose. Once i tightened that sucka the motor idled like a beauty. I knew pedaling all the time to start the motor after every stop wasnt right...lol thanks .rd.
 
It's what this place is all about..Thanks! .bld.dnut
 

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cool, about the idler..should it be all the way down, or how much tension do you wanna put on the idler screw? does it make more noise as you turn the screw more in? any effect on the Rpms?
 
the idle screw will make the engine make moe noise as it increases the rpms when turn in. you can adjust the idle screw for the best idle that suits you and you can turn it in for more idle speed when cold and turn it out for less idle speed when its warmed up. try to find the best comprmise for both.
the choke lever is on when you pull the choke lever up and the choke lever is off when you push the lever down you can take off the aircleaner and see first hand how it works very simple.
If your bike runs fine with the stock china plug use it I have worn out one china plug and now using a champion plug in its place. check out the classic posts lots of info there most of mine are on the second pages. If you need answers to questions (PM me for quicker help) or post it on this forum.
Norman
 
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