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Changzuki, who also calls himself Crazy Jerry. I found him as Crazy Jerry long before I ever discovered Ecomodder, and I was reading up on diesel-converted bikes. He's done exactly what you're talking about with a modest little Suzuki and a cheap Chinese single-pot pull-start diesel. If you're not in a hurry but have a long way to go, the mileage on Jerry's bike can crack past 115 mpg, even if the engine doesn't have enough twist to pull the bike much beyond 60mph.