Re: In all honesty how many miles have you gotten out of a HT engine before it died??
I've had 3 engines. 1st engine lasted for about 3 months - cause leaky intake gasket.
2nd engine lasted about 6 months - cause wrist bin bearing, and melted aluminum head gasket went into the chamber. 3rd Engine - more than a year, cause wrist pin bearing again. 1st and 2nd engine came from ZBox. 3rd engine came from Rock Solid (RSE). Rebuild a 4th one with parts from RSE. On my way of rebuilding 2 other engines, with parts from RSE. Difference also is I started using Walbro Carb, where you can properly tune the mixture at WOT and at Idle. I'm also using a chainsaw wrist pin bearing, but still looking for a good bushing to replace this bearing.Too bad RSE does'nt sell bushings.Gaskets, i make my own from Garlock heat resistant gaskets. And instead of an aluminum head gasket, i polished the surfaces and use a super high temperature silicon gasket. I also did some port matching. The 2nd engine that lasted 6 months, was on a shifter kit. Still using the shifter kit. In terms of Kilometers, I usually average maybe around 500 to 600 kms per month. The way I see it, it's probably the carbon build up that shortens the lifespan. So using a stock carb and no port matching makes the carbon build up faster. It's recommended to decarbonize 2 stroke engine every 3 months or so. So I also do the decarbonizing procedure. You can find decarbonizing in some of the threads here, and you can also search WWW.
Hope this helps...