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Motorized Bicycle Trouble Shooting Use this area to post problems that may arise that you could use some help in figuring out what is wrong with their bicycle motor and what needs to be done to achieve top performance.

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  #1  
Old 04-05-2009, 04:43 PM
i-paint i-paint is offline
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Default Won't start when hot!

I have a Dax F80 engine with 235 miles. I have a rope pull start and a SBP shifter kit.. The carburetor is a Dellorto SHA. It starts, runs and idles fine when it is cold. After running for a while and it is warmed up, if it dies or I shut it off, it won't start with the rope pull. I can use the pedals (probably spins the engine faster) and it starts right up. I need some help, any ideas?

Thanks, Larry
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  #2  
Old 04-05-2009, 05:06 PM
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MB-Monkey MB-Monkey is offline
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Default Re: Won't start when hot!

pull starts on the small 2 stroke is known to not spin the motor fast enough. you could replace the return mech and rope and see if that helps but that cost you could prob get a new pull start.
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Old 04-05-2009, 06:05 PM
i-paint i-paint is offline
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Default Re: Won't start when hot!

I can't figure why it starts fine with the rope when it is cold and not when it is hot.

Larry
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Old 04-05-2009, 08:47 PM
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Bikeguy Joe Bikeguy Joe is offline
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Default Re: Won't start when hot!

Try using just a little choke, even when the engine is warm.

I found that even in the summer, if I shut the bikes off for more than a few minutes, they always started better with a touch of the primer, or a little choke.
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Old 04-05-2009, 09:05 PM
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Default Re: Won't start when hot!

a cold motor is going to have more compression once the motor and parts are hot plenty of places to loose compression
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Old 04-06-2009, 10:48 PM
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2door 2door is offline
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Default Re: Won't start when hot!

I have to agree with Joe. I've found my engines always respond better with a little choke on starts, cold or hot. One cause of hard hot starts can be fuel atomization in the carb and intake. The fuel vapor actually evaporates into a very lean mixture which a little choke, (reduced air) can remedy. Good luck.
Tom
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