Carby problem, I think...

[Stewy138]

I have a PE175C which I recently changed the carby from 32mm to 34mm.  The other change at the same time was fitting an inner rotor ignition with an RM125A CDI.

Anyway, when I ride the old gal hard (no I'm not talking about my personal life, I'm referring to the PE now) then back off the throttle, eg on a downhill section, the engine starts to die (like its running out of fuel).  If I give it a good handful of throttle it recovers ok but will start to die away again if I start to back off.  Only does this when the engine is hot and doesnt seem to happen when I'm not riding as hard, and the engine presumably is a bit cooler.

Its not over-revving when it dies, so I dont think its running lean.  The plug is sooty and slightly oily after a ride.

Any thoughts  ?
Thanks,
Stewy.

[vandy010]

what size pilot jet Stewy?

[Stewy138]

Hey Vandy,

Yes i was thinking along those lines...the new card was apparently from an RM125M and the jets were all way different to the ones in the 32mm PE carb.  So I changed out all the jets from the 32 PE carb into the 34mm body.  Then went to a significantly bigger main jet (260, original was 190).  Logic tells me that the pilot would need to be larger too.

Will extract it and have a look...

[Lozza]

Do a proper plug chop and post a pic of the plug.Alternatively kill the engine while the problem exists.

[oldyzman]

Is there any possibility the choke is faulty and not turning off properly..
Brett

[oldfart]

check to see is float level is correct height.

[Davey Crocket]

Make sure your misses hasnt burnt the muffins