My GTS250 has always been extremely reliable, but now has a fault that I can't resolve.
Last Wednesday, coming home on the freeway at about 120 kph, the engine hiccupped and then stalled. It would not restart. After a few minutes of cooling, it would start, but stalled again as soon as I opened the throttle. I eventually established that after a bit of cooling, it would idle and rev slightly, but cut out again at 3000 rpm. I was able to crawl home at little above idling revs. I checked the fuel level and the spark plug lead and cap, and they were all fine.
Fiddling the wiring loops around the engine, I found that jiggling one of the Malossi Force-Master wires cause the engine to cut out. So I removed the Force-Master from the equation by un-installing it (destalling?). No change. My ignition and ECU are all bog-standard now.
The next day the engine started perfectly, and seemed fine. So I went for a ride. As soon as I got out of the 50 kph suburbs I opened the throttle wide, and the engine stalled. Same symptoms again.
This sounds a bit like the famous fuel pump problem, but my scooter is the wrong vintage (2007). The fuel pump problem involves the engine not restarting after a run, until it has cooled down. But my engine fails at speed, and then will only restart to idling, until it has cooled down properly.
I have a spare fuel pump, but am reluctant to go to all the hassle of fitting it until I am sure that is where the problem is. Spoke to a car mechanic friend last night, and he insists my symptoms indicate ignition coil problems. Anyone had these symptoms before?