Aprilia rx50 2004 dies after 5 minutes

[wheelers]

good luck too you, these are the worst problems!!
sounds like something heating up after time, could be piston growing and semi seizing (insufficient clearance) . on a scoot could be electric choke not cutting off and over fuelling, could be tappet gap closing up, could be cdi overheating.
finally on a fuelling point, low compression ,lack of vacuum or hole / cracking of vacuum pipe not operating fuel tap diaphragm.

cross out any of the above that do not apply, ie 2 or 4 stroke valves. manual or vacuum op tap etc good luck

[paddee]

..some thing over heating, my thoughts indeed.

piston and rings seem ok. But I've not got kit to do a proper pressure test.
manual choke. don't think it's that.
I was thinking spark plug breaking down, but it's only a few weeks old (could be some fault in it though?)
Possibly the 'coil' We did have a plug fall off it last week. Not so simple this time. Maybe inder load, this is heating up and failing? But then when spark plug out of head, it is sparking
as it's a 2 stroke, not alot of moving parts.
There's no vacuum pipe from card. Just fuel in, oil in, over flow and throttle cable.