96 sprint engine cutting out intermittently

[illusionist]

Bike was running fine until last night when after a short 80mph stretch it cut out at a set of lights and refused to restart.
All other electrics OK. It suddenly restarted after 10mins (having refused to start until then) but only ran for 300yards before cutting out again. This pattern continued. Interestingly engine would stay running if kept above 2500 rpm, but drop to tick over and it would cut out. Engine does not die gradually - making me think its more likely to be electrics rather than fuel.
Any one experienced anything similar?

[pendraig]

Try running with petcock turned to "prime". In the "on" position, the petcock uses engine vacuum to keep the fuel passage open. If the diaphragm has a leak, it might function at higher revs, when there is a greater engine vacuum, and then shut down at idle. It's a shot in the dark, but probably worth checking.

[illusionist]

HI pendraig
Thanks for reply. I've had triumphs for over 10 years now and never realised up was prime!!
Would you expect the engine to cut out so quickly if it were a petcock fault?
Scanning around the rest of the forum I've come across a number of members who've had similar problems with higher (!) mileage bikes (mine has 32K). Nothing conclusive though. The ignition pick up and broken wires appear to be common culprits too...

[TrumpetSprint]

My 98 Sprint would cut out at traffic lights. Sometimes restart almost immediately and sometimes after several minutes. J98sprint put me on to the ignition sensor. Replaced it and haven't had a problem since. J98 and I had similar problems at a little over 30K on the odometer. Might be worth looking into. The part was about $60-$70 here in the states and about an hours worth of shop labor (I didn't have the tool to break the small torx screws loose to replace it).

[illusionist]

Many thanks. I'll replace and let you know outcome.