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Christian Bynum's Classic BMW Motorcycles: 1980 R100T Racer
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Motorcycle Data Sheet

Model: 1980 BMW R100T

Engine: 980cc 2-valve boxer twin upgraded to 9.5:1 CR (67 HP)

Years of Production: 1979-1984

Number Produced: 21,928

Purchase Date: September 2003

Previous Location: Webster, NC

Previous Owners: Unknown

Mileage at Purchase: 0 (Rebuilt)

Mileage Since Engine Rebuild: 0

Restoration Projection: A lot...

Restoration Costs to Date: $960


Background

For a full year I had wanted to build a highly modified Airhead bike that was fast and fun. I had planned out two cafe racer projects and given up twice, choosing more sensible routes for my motorcycle restorations. Then I jumped on two opportunities to bring my hot rod dreams to fruition...

First, I purchased a strong, sound /7 frame from a fellow Airhead enthusiast in North Carolina with whom I had swapped parts many times before. He offered me a superb price; coast-to-coast shipping cost me nearly twice what I paid for the chassis itself. When it arrived it was in such serviceable condition that repainting or powdercoating it was purely elective.

Second, I scored a very good deal on a complete 980cc R100 engine from my mechanic. It had been the powerplant for a 1978 R100/7 belonging to a local rider I knew, who had been hit by a car and suffered a crash. My mechanic had purchased the core of the wreck; the fork was totalled and the frame was a mess at the steering head, but rearward everything was sound.

With this acquisition, I now had what I required to begin my experiment in building a high-performance Airhead. As I mused and did my research, my concept began to evolve beyond a classically styled cafe racer toward a full-on track-prepped racing motorcycle with few or no concessions to street-legal riding. As I learned more about vintage race events -- especially in the Pacific Northwest -- I found out it was more worthwhile to build a 750cc track bike than a 1000cc, so this project drifted back towards the ton-up look, leaving my third /5 chassis to get tuned for the oval.

Restoration

Right now, this bike exists only as a nearly complete rolling chassis, as yet without electrics. A /7 frame makes a good platform for an Airhead cafe racer project because in stock condition, it is better braced and has bigger strengthening gussets than the frames of the earier /5 and /6 series.

A dual disc brake front end with a machined billet upper triple clamp (for increased rigidity) was mandatory for this project, as was a sleek /5 nacelle-type headlamp bucket with built-in gauges, to complement the long, low lines of the bike. I purchased a custom fiberglass boat tail solo seat and cowl, a nice (if not 100% faithful) replica version of the famous late-70's KnoScher bodywork, from Ed West at 1977-78 stock color for the /7 touring models, eschewing the white pinstripes in favor of solid simplicity. The bike will have black side covers and a black rear fender.

I found a low profile dual-intensity LED tail light with a lustrous chrome billet housing from Custom Dynamics, an East Coast chopper shop. My original intention was to flush-mount th billet tail light, so that only the trim ring and lens were outside the boat tail's glass, but I realized once I had all the parts in hand that the built-in rear bracket on the seat cowl prevented cutting the 2" diameter hole necessary for the flush mount. I opted for a neat surface mount instead, and the tail light's chrome body protrudes at an acceptable 3/4".

I have many other parts slated for use that are still in boxes, including some nice 38mm Dell'Orto accelerator pump carburetors and a lightened 111-tooth flywheel to provide crisp throttle response and smooth shifting. I want to refit the engine with high-compressison sport pistons to eek out a some extra horsepower. For now I have the stock '74-78 spoke wheelset mounted, but eventually this bike will be shod with '79-84 BMW snowflake mag wheels to enhance its sporting style. I also want to weld bosses onto the frame for San Jose bolt-on frame braces, to beef up the main frame...

Reconstruction Chronology

September 2003

  • Mounted subframe and front fork on main frame
October 2003
  • Installed swingarm and completed assembly of rolling chassis

Acknowledgments

Thanks to the following individuals for assisting in this restoration project: Barry Bialik, Howard Bialik, Barbara Bynum, Jeff Clevenger, Cameron Hoverter, Vince Martinez, Charlie Moore, Rich O'Connor, DL Powers, Mike Shropshire, Bo Stewart, Mick Vallantine, Ed West, and Ted Witting.


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