PX125EFL cutting out :(

[owen9bd]

Hi
Looking for some help & advice? I have a 1991 Vespa PX125EFL it starts second kick & will tick over fine but after riding for 2 or 3 miles starts to misfire & will then cut out & will not start until it has gone completely cold. I have replaced the spark plug (Spark present when non start), striped & cleaned the carb, checked the condition disc valve (Crank), removed head checked condition of Piston crown, Barrel & combustion chamber in head (good compression), drained fuel tank & used new fuel from different filling station &checked wiring connections at CDI for corrosion. still no joy any help is much appreciated
Cheers

[kru251]

Best to try with a known functioning CDI unit as that would sound the favourite offender from where I'm sitting now!

[owen9bd]

It had crossed my mind will see if I can get one tomorrow? also thought I would bring my multi meter home from work & double check the wiring from the Stator unit
Thanks for the advice

[sbwnik]

Seconded on the CDI.

[pxguru]

CDI thirded

[owen9bd]

Hi Guys
Just thought I would give an update
Fitted a new CDI unit still the same checked Stator found it to be going open circuit when engine warm. Fitted new Stator at the weekend have done about 50 mile on it since without any problem.
thanks again for the advice
Chris

[kru251]

Well found! Blimey, try doing that mileage around here at the moment and you'd arrive back looking as if you'd been riding around a Siberian Salt Mine all week!!!!

[pxguru]

Yeah, well done! that kind of fault can be tricky.

Did you change the whole stator plate? Or just the pick up? Did it look like the flywheel was rubbing on it?

[sbwnik]

I was about to ask the same question, but with the symptoms I'd assume just a cooked coil. And sign of rubbing/wear on the pick up or any of the coils and I'd be checking my bearings.

[colin4255]

Glad you found out what was wrong. BTW similar issues can be caused by someone fitting a fuel pipe that is too long. ie, its long enough so it drops down below the level of the carb. My PX was like that when I bought it. Worked fine for 5 miles then died. left it a bit, it worked again. Took ages to discover that issue. Pipe should be no longer than 24" Worth mentioning...