Ha, that's a good one. The motorcycle industry foisted works-type 4 strokes on the dirt riding public, under the guise of "getting rid of those dirty two strokes"...and we end up with complex, over stressed motorcycle engines with the lifespan of about 30 hours, before a TOTAL rebuild is needed, costing around three thousand bucks.
Heaven forbid we have a true 500cc two stroke that lasts for years and years, puts out fantastic power, everywhere in the powerband, and goes like stink. I purchased a CR500R in 1987 (the best year if you ask me) and it never wore out. Or sure, I put a few clutches in it, and a few rings, only one .60 over bore, but it lasted 4 ever, and was fast. The lower end was stock, with the exception of one set of crank seals.