Why does my Triumph TT600 cut out?

Q. I have a 2002 Triumph TT600 with 20,000 miles on the clock. I’m having intermittent issues with it cutting out. The bike will start fine to begin with, but cuts out mid-ride. When it does this the engine management light can be seen to continuously flicker and the main power relay can be heard flicking on and off rapidly.

If I turn the ignition completely off and on again, usually the engine management light and the relay will continue ‘flickering’ but eventually the fuel pump (which is fed by this relay) will prime as normal and the bike starts only to cut out again a mile down the road.

At first I thought it was a faulty fuel pump, which I then replaced only to find out it was being controlled by this relay. I’ve tried replacing the relay but it’s made no difference. Since then I’ve checked sidestand switch, kill switch, battery, rectifier, bad connections and alarm, but all seem fine.

I then booked it into my local Triumph dealer who had a look and said it was a corroded coil pack (for the spark plug), they replaced this and the plugs, but 50 miles later the problem has reared its head again.
Ttwill, MCN forums
 
A. If the coil pack was faulty the bike would misfire, not cut out completely. I wonder if the battery isn’t losing charge, then when you take the load off it, it recovers to some extent. However, that probably wouldn’t be enough of a recovery to spin the engine over again. It would be worth checking the battery voltage, it should be 13.5V to 14V with the engine running, 12.5V with it off.

Or it might be a power issue to the fuel pump relay. This may be a poor connection somewhere or your alarm pcb going into fault mode. Try running a temporary live from the battery to the relay so it is running regardless of the ignition and alarm and then go for a ride.

If the fault doesn’t appear then at least you have tracked down the direction to go in. The alarm could be the culprit, but if it’s the factory-fit, then that shuts down all the engine management, so you’d have no sign of life at all. But if it’s aftermarket, then it might kill the ignition and fuel pump circuits independently.

If your alarm is the dealer/factory-fit Datatool, then they should have supplied you with a plug with two green looped wires.This plugs in the back of the main fuse box in place of the alarm plug, in case the alarm goes to fault.

The regulator/rectifiers on those bikes are pretty good, but the stators are pretty poor, if part of that has cooked, that could give you the symptoms you’re describing.