Aprilia rx50 2004 dies after 5 minutes

Hi,
If any one can assist please? I've tried searching, but not finding anything relevant. Unless I've missed some results.

My son's bike is cutting out after 5 minuted riding. Then will not start.

Last night, it cut out after 5 minutes (or so) went out to help him, seemed to start after about 20 minutes.
Nearly made it back home, engine cut out again. (about 5 minutes ride)

I've removed carb, stripped and cleaned.
Checked reeds, cleaned.
Checked head and piston rings, all look good. New gasket set installed.
New spark plug fitted.

Started easily
It idles happily for about 10 - 15 minutes.

Son takes it out for some testing, 5 minutes, it's cut out, non starting.

I have a spark with spark with plug held against cylinder head. Fuel is flowing to card.

He bought it last month, and so far has had minimal riding on bike.
He did ride all way from Bournemouth no issues (about 2 hours)

Paddee

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

..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.

Bit of a long shot, but could the choke be sticking ? This could cause the engine to flood and cut out.

when it cuts out is there fuel in the carb at that time?
Don't check it a few minutes later, loosen the screw in the float bowl straight away.

Or

Try opening the filler cap and road testing it to see if the tank breather is blocked up, preventing fuel flow.

Was thinking of the breather hole myself mate, worth checking, good shout.

removed filler cap, still no good. If I remove fuel pipe from bottom of tank, fuel flows plenty.
The float chamber is not so accessible. Take about 10+ mins to get at it. So, the carb is the only thing I can't really check so well.
I've removed, sprayed carb cleaner all through it, and cleaned/dried with compressed air.
I do think it's fuel related though (just my thoughts)
The bike is also so powerless when moving off from stand still. If that is a hint to anything else? Unless all 50's are sluggish to get going from 0mph?

A 50 is never going to be quick, It's all relative, really

Have you actually removed the carb from the bike?

Is the exhaust or air filter blocked?

Has the bike had any other work or modifications done to it?

Carb had been removed, dismantled, cleaned and refitted. There was dirt in the Carb.
Air filter not blocked. Will double check exhaust.
I believe it's non standard carb and non standard exhaust.

Quote:

---

Originally Posted by paddee

I believe it's non standard carb and non standard exhaust.

---

That doesn't make things easy.

What carb is it?
Is the jetting right?

Where in Melksham are you?