1977 Daytona Orange R100 (R90s clone)

ID# 023858
3 Downing Ct
Chester, NJ 07930-3011
United States
201 506-7101 (Main Phone)
(Mobile Phone)
$9,000.00 (Or Best Offer)
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Buyer responsible for arranging and paying shipping costs
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Category  Classic Airheads
1977 R100 Daytona Orange with less than 2000 miles on a complete ground up rebuild is badge as a R90s. Portfolio of the start to finish construction process parts photos are available via PM. Everything work including clock. Original tool kit, owners manual and shop manual included.

The construction differences and modifications are:

Actual frame is the later (stronger from factory) ’77 R100S. This frame was as you know a dedicated “Sears Point” club race bike that was built and campaigned by the owner of "Parts Unlimited” in San Francisco during the 1980’s. The modifications to the frame are several specific reinforcement plates installed around the front fork support tube and the area around the rear portion of the main backbone tube and down tube transition points. The frame support tubes are fastened using tapered male joints that match tapered female connectors with large stainless cap screws. Interestingly these frame supports are a composite construction of steel connection joints and TIG welded and a butted joint to 7075 aluminum tubing, instead of the normal (heavy) chrome molly tubing. I did not discover this until later during construction. They are rare parts and I have sales literature in an old catalog. The components were made and sold though San Jose BMW and later CC Products. (The brakes are now controlled by a ’85- on 15 mm handlebar mounted BMW modern direct master cylinder and the rotors are Italian made Gramicci. Brake pads are Ferodo organic. The brake lines are custom made TFE lined stainless braided with a black Kevlar outer lining.

Suspension is new Works Performance Street tracker shocks with dual spring rates, threaded pre-load adjustment and ARS cross over levers. These are a bit shorter that the BMW shocks and are matched to lower the entire bike about 1-1/2 inches. To lower the front of the bike, I used shorter BMW RS springs with an additional “anti-dive spring” of my own selection to give the fork a very progressive feel and stronger resistance towards the last 1/3 travel distance during extreme compression. The top fork tube support from San Jose BMW and the Telifix adjustable upper fork slider brace keep the fork in accurate alignment and minimize this old under developed design and it's deficiencies. The suspension now feels very modern and controlled compared to the stock 1070’s BMW solution.

The front wheel is a brand new BMW wheel for all 1981 on bikes and the rear is the OEM wheel rebuilt, polished with high tensile steel spokes. Tires are modern Continental high performance bias type.

The rebuilt engine in this bike is a 1978 R100 (the strongest design of the early Airheads) with major changes using BMW components. The cylinders are R90/6 (torque plate honed), the pistons are R90S 9.5:1 with modern Hastings three piece oil ring sets. The flywheel was professionally lightened and balanced and the ignition is now triggered by an Dyna III electronic ignition system and should not require further maintenance except for a occasional lubrication of the advance mechanism. The heads are R100/7 that have the improved rocker arm mounting scheme that was used until the end of production in 1995. The final compression ratio is about 9.2:1 with the combination of parts used. The motor should run on mid-grade gasoline.

The Carburetors are later 32 mm Bing Constant Velocity type that are of the best put on the BMW Airheads. These were used from 1981 through the last of production in 1995 and have the choke handle on the handlebars. Later throttle and choke cables are used that use a single cable transitioning to dual cables for superior control and reliability. They stay adjusted better too.

The transmission is the later improved '77 designed that was disassembled, inspected and had new shifting components installed. Final drive ratio is same as all R90S bikes at 3.0:1 (33/11). This matches the NOS speedometer. The shift linkage is '78 R100RS type that moved the pivot about the ankle rotation point.

The entire wire harness is a '78 R100RS type to provide the connection to the later 1978 electronic Tachometer. The L H switch control is actual R90S that allow the headlight to be turned off and gives the option of a park position lighting scheme. The RH switch is also period correct R90S with the turn signals controlled with the then new vertical switch design and a DOT kill switch. The matching instruments (Speedometer, Electronic Tachometer, volt meter and quartz clock) are all the '78 on green number type R90S instruments were all mechanical and had white numerals. Spark plug wires are R100 type. (R90S used the /6 type).

The top starter/engine cover is actual R90S with restored paint scheme. Mirrors are the short black '85 on R80 style and with the trimmed USA bars give a nice rear view yet are closer to the bikes center line and blend in nice.

Located in NJ, buyer pays for and arranges shipping $9,000.00 PayPal accepted
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