BMW R90S Sport Bike

BMW  R90S  Sport Bike

  This was my sons motorcycle which he purchased new in 1976. He rode it very little and was not satisfied with the performance. In 1981 he sent the motor to BMW of San Jose Calf. to build it into a !000cc Enderance  Raceing Motor. I helped him put every thing together and make it run. he was thrilled with the performance of it and was planning to race it. He was killed in a small plane crash in 1985. I have had it ever since. stored in my shop . It is time for it to go. I don't know all the particulars about it. but I will tell what I can. It was bored to 1000cc. the rods were replaced with much stronger  racing ones. the pistons are 12. 5 :1 compression Jahns. the camshaft is an Erson. I don't know what the lift and duration are but it is much bigger than stock. stronger push rods and rocker arms where installed.  The heads were ported and polished by Jerry Branch and duel spark plugs added. The fly wheel was lightened and balanced and the entire rotating assembly balanced. There is more than likely much more that was done here but. I just don't know. I has a Dyna Three ignition system. 4 mm Mikuni carburators and an open exhaust. The motorcycle has a lengthen and braced swing arm. The forks where worked on . on't know what was done. The motorcycle has less than 50 miles on the motor.  The gas tank. fairing and front fender where removed for fresh paint. It is beautiful. It would not take much to put this bike back on the road or track.

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