MTB that needs some TLC = not much value. As a keeper, it would be an interesting bike with the very unusual frame style. If you are trying to sell it, I would clean it really good, air up the tires, replace any rusty cables, and then sell in the $100 to $150 max range. As is, not much. Worth your time if you are the seller to do a little clean up. As a buyer, should be able to get it for $40 to $50 in as is condition.
That appears to be an original 1989 Alien frame. The elevated chainstay design caused quite a fuss for a few years, then largely died away, at least for hardtails. Thes were originally equipped with Shimano Deore XT-II and sold for $1000 US. SunTour XCE is quite a step down and would have knocked the retail price in almost half. I don't know what the Rochester market is like, nor the mechanical condition (outside of apparently flat and cheap tures) but cosmetically it appears surpisingly clean.
The Alien was the top of the line MTB for Nishiki that year. The bike you're looking at has the rounded tubing that I believe is steel. In 1990 through 93, the Alien had box/rectangular tubing and was made of aluminum. The later Aliens still bring nice bucks on ebay if you can find one with the headtube not cracked. The steel model was downgraded to the second place model in the 1990 line-up. The Ariel and the Cascade shared the steel frame.
If you add a nice suspension fork and some decent brakes, like V brakes those elevated chain stay bikes make great rides on single track as they have great handling charachteristics, very stable. I compared mine directly to a same vintage (1992) Trek 8500. The Trek had a superior Rock Shox air fork but couldn't come close to the handling of the Nishiki. Here's a pic I took last year out at Harris Lake park of my 92 Ariel. Note how similar it is to the 89 Alien. I believe the frames are identical.
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