Starting cycle.

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Tue 3 Aug 2004 00:08
Starting cycle. - Gregory R
I have a majesty 125cc scooter (automatic trans). The problem I have is that it will start first time every time. However, if I switch the scooter engine off, and then switch it back on in less than 15 minutes, it can take two attempts to restart. It is reluctant to start from restart and cuts off on first attempt in 60% of cases.

What could this be? The battery is fine, the leads are fine, the air filter is new and the oil is fresh. The mileage is only 21,000 miles and the bike is 2 years old.

Also, how many miles should I expect this engine to last me with regular oil changes and frequent servicing.

Any thoughts would be appreciated.


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Tue 3 Aug 2004 01:37
Starting cycle. - Dynamic Dave
It is reluctant to start from restart and
cuts off on first attempt in 60% of cases.
What could this be?


Sounds like fuel evaporation to me. ie, heat from the engine once it\'s parked up evaporates the fuel from the carb. Try wrapping the carb in tin foil as a temp measure to help insolate it from the heat of the engine.

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Tue 3 Aug 2004 11:18
Starting cycle. - Mapmaker
Possibly flooded?

Try putting the accelerator pedal on the floor when turning it over. (Or opening the throttle, or whatever it is you do!)
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Tue 3 Aug 2004 11:20
Starting cycle. - Dynamic Dave
Possibly flooded?
Try putting the accelerator pedal on the floor when turning it
over. (Or opening the throttle, or whatever it is you
do!)


From experience, motorbikes generally won't start with the throttle wide open.

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Tue 3 Aug 2004 11:25
Starting cycle. - Mapmaker
So what do you do if you flood it?
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Tue 3 Aug 2004 12:30
Starting cycle. - Mark (RLBS)
>>So what do you do if you flood it?

With my Norton you take a plug out and hold a match near the hole. Of course, things *might* have change a little bit since the 50s.
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Tue 3 Aug 2004 13:31
Starting cycle. - Dynamic Dave
So what do you do if you flood it?


Granted, that'll probably clear the flooding, but you'll have to shut the throttle down again before it'll start.

But how can the bike become flooded after being parked for ¼ hour, and generally starts at the 2nd attempt?

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Tue 3 Aug 2004 13:41
Starting cycle. - Mapmaker
>>how can it be flooded?

If it's over rich. So restarting when hot, it's always flooded. Wait 15 minutes & it's no longer a problem as the petrol drains into the sump.

I had a Renault 21 that started beautifully from cold, but when hot & recently running it would be over rich (you could smell it) & so foot on the floor made it start first time every time, otherwise it would only go second or third time.

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Tue 3 Aug 2004 14:22
Starting cycle. - patently
But how can the bike become flooded after being parked for
¼ hour, and generally starts at the 2nd attempt?

Easy - heat from the engine is reaching a fuel line. The fuel in that part of the line evaporates and forms a gas plug behind the fuel further down the line. This plug expands as the fuel evaporates and forces the fuel into the cylinder, flooding it.

Hands up everyone who learnt to fly the Bulldog light aircraft. The starting procedure for this was very involved and required you to know EXACTLY how long the aircraft had sat since it last ran.
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