Both are good bikes, depending on condition. The 86 SEI is fuel injected only made one year The 85 LTD is also fuel injected only made one year. There are parts that might be hard to find, but they usually are reliable and not problematic if properly serviced. The SEI and LTD were the only 1200's that had electronic cruise until the 1987Aspencade, the last year of the 1200. The 92 interstate is a basic bike, no reverse, no cruise, but also a good bike. It would depend on how the bikes were maintained, but with the 92 only being an interstate The $4,000 is pretty close to top dollar on that bike and the 86 sei would be closer to an average price for that year model. I would probably choose the 86 sei over the 92 interstate especially if funds were limited, more bang for the buck, if you like all the options. The only thing the 92 has going for it is it's a 1500, so you either get the 4 cyl 1200 with all the goodies or the 6 cyl 1500 stripped down. Both good bikes just depends on your preferences of what goodies you like.