Sorry all, I know this fault has been spoken about before but was just wondering if somebody could just give me a little more info. My TY175 cuts out when hot, no spark, i have noticed it will not cause any problems on a cold day, but on a warm day after a few sections it will just cut out,let it cool for 5 mins and then your away again.So far i have replaced the HT coil,the wiring,points and condenser.Its the ignition source coil which i have some doubts about.I have measured the resistance and its about 1.8 ohms cold and rises to about 3 ohms when you heat it up with a hair dryer.Not sure what else there is to check but somebody did suggest that the condenser although not very old could be breaking down.I have started to think electronic ignition,but

Andy,

These faults can often be difficult to find but from the symptoms you describe it could be that the black wire from the source coil is shorting ....... as the engine heats up the plastic can melt and then short out. As it cools down the plastic self seals and it will start. Have a look at the black wire and see if it hard and brittle.... if so replace. Check the faces on the points are bright and no covering or black spots. Set at 15 thou, likewise plug at 22 thou. Last try it with the kill switch wire disconnected as that could also be shorting out when hot.

Tony

Thanks for that info tony283, that black wire from the source coil, if you mean the copper wire that is part of the coil that is soldered on to the condenser that has a black sleeve,then yes I have checked this and it does look OK,I removed the wire from the condeser and slid off the black sleeve.The main wires from the condenser to the HT coil have been replaced and I did try removing the kill switch.I think I will try and cook the condenser with a hair dryer and check the readings on it just to see if it shorts out.Thanks again, and if you have any more ideas please let me know.