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Contact Jim: franzen@culayer.com
1971 BMW R75S
"A skittish motorbike with a touch of blood in it is better than all the riding animals on earth"
-T.E. Lawrence
Not an actual BMW offering, this custom 'S' or ''Sport'' version of the R75/5 is the sport bike BMW neglected to build. It falls perfectly in-between the mid 60's R69S and the mid 70's R90S in both displacement and era.
Custom designs: 'bobbed' front fender, solo saddle and sport rear fender
The performance equation is nicely balanced on this one-of-a-kind machine. In addition to a more powerful engine came frame stiffening as well as suspension and braking improvements. To fulfill the sport concept, a custom designed composite 'bobbed' front fender, solo saddle and rear fender were created.
Features of the R75S:
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| Progressive front fork springs |
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| R75 valve covers with 'Rennsport' style allen screw removal |
| Timing cover vented for improved cooling |
| R100 cam |
| Ported and dual-plugged R75 cylinder heads, machined to fit R80 cylinders |
| Black Diamond high-flow intake and exhaust valves |
| 280 Watt output alternator |
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| Rods, rocker arms and all surfaces have been relieved, polished and where applicable, balanced to 1/50 of a gram |
| 5 speed (polished) transmission |
| Akront 2.15 aluminum alloys w/SS spokes |
| Gold cadmium plated battery tray (for corrosion resistance) |
| Polished final drive |
| (Nothing implies speed and autonomy like a solo saddle) |
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| Stainless steel "Staintune" exhaust system |
| Deep oil sump |
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| Koni Shocks |
'The engine and all exposed
aluminum has been relieved and polished. About five pounds of aluminum was removed.
The engine/trans are R-80 units. R-75 covers were reworked and fit to retain the early R
look. Heads were dual plugged and ported and are fed by late model Bings.
Wheels are Akront units laced with SS spokes, sporting Metzler rubber. Progressive springs
up front and Koni's aft. The swingarm was trussed and the frame has been cleaned of
extraneous tabs/features.''
Note!!!
My bike was built from the "touring" bike in the article. The LWB "Sport" cousin of my bike in the article has the stock rear fender and taillight.
The building of the bike....
The finished bike re-united with its maker Kevin McDonald, several months after completion. This photo was taken on a brisk November day after Kevin moved from Hawaii to Chicago.
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