So far the differences I have noticed are: crankshaft, rod, piston, counterbalance (I assume), cylinder linner - looks like 650 cylinder?, Primary drive ratio different 32/71, no starter torque limmiter or decompression actuator, it is a 650 head, carb (40mm), camshaft ? output shaft has space for belt drive pully but 400 is chain drive, I have to check out gear ratios, all frame parts, electrics look 650 execpt muffler ? Does any one have any futher details ???

The LS400 has always been a chain drive (as far as I know) and it has a different final drive ratio then the LS650. About 15/48 vs 23/68 for the LS650. I have seen a 650 moded to chain drive in Canada (home). I dought you would be able to get the right pullys & belts to mod a 400 to belt drive. After riding belt drive on my sporster for many years I love it (much better then chain).

This one is realy bucharded but it had a "Green Book" (Thai registration) so was legal. I have to use the steering head with VIN on it !!  Cost $1,000 Cdn. The other one (good one) had no "green book" so was not legal and cost $650 Cdn. Gettig a new bike here from Canada would cost $2,000 shipping, then 20% duty if parts or 80% duty if whole bike than at least $2,000 to get a green book for it. So a $5,000 LS650 from Canada becomes very expensive!!! Much cheaper to restore a 20 yr old bike - as far as I know both these bikes are early 1990's.