I've had no problem at 10,000 miles .. Targa LX A35 engine .. except I had to replace a $3 'clutch' which was still working but getting worn. There is some concern among some posters here on the forum about the A55 rubber clutch giving out at 500 miles but that seems to be speculation at this point. Personally, I believe the problem almost everyone is having with injection is forgetting to refill their oil tank. That's my opinion based on the pump just being too simple to break down, Tomos engineering and craftsmanship being superior, and the pump is pumping oil which keeps the pump well lubricated. But if you do switch to oil mixed gas the mixture is definitely 50:1 for the A35 according to Tomos' literature, and more s unnecessary and may cause you carbon build up, exhaust plugging, etc as well as unnecessary pollution.