GL-500 AKA Supermotoscramblerstein (#supermotoscramblerstein)
Another build complete, we hope the results speak for themselves.
How we got here…
The Supermotoscramblerstein build By Other Life Cycles.
This build started life as a 1981 Honda Gl500 Silver wing (aka: the poor man’s Goldwing). Not an overly high horsepower base – as stock, it puts out 50hp at 9000 rpm, quoted top speed is just over the ton. On top of all that, when you strip the bike down past the plastic and trim, it can look awkward, even a little unbalanced. As I write that, I kinda wonder what possessed me to start with this base. All I can say is that I like a challenge, and it is an opposed twin water-cooled engine that responds pretty well to being kicked in the pants with some simple modifications.
I left the engine completely stock and simply cleaned it up and repainted it. I polished the valve covers, refurbished the engine badges, and added some visual touches to help make it look a bit more utilitarian. The stock radiator guard was removed and a new one was designed and fabricated out of perforated aluminum sheet. We also fabricated and welded a smaller aluminum overflow tank for the radiator and moved it from way down in the belly of the bike up to the left side of the radiator. This overflow tank includes a custom fabricated mounting bracket also out of aluminum. I felt like this was a good move because it embraces the asymmetry of the bike and engine, plus aluminum is lightweight and awesome. The performance of the engine was improved by fitting a Domino throttle and a set of round-slide Mikuni VM34 carbs from Murray’s Carbs to replace the stock CV carbs. A set of lightly ported and polished aluminum intake manifolds were also fitted that feed fuel and air into the cylinders more directly. All is capped off with pod filters from our friends at K&N filtration.
With the fuel supply side of the engine bumped up a little bit, I dumped the stock 2 into 2 “H-box” travesty of an exhaust system and designed and built up a shorter more streamlined stainless steel 2 into 2 exhaust tipped with short 8 inch slip-on mufflers from Cone Engineering. Since these pipes were tucked in close to the frame and engine, I machined heat shields out of aluminum that harken back to the old Honda CL scrambler pipes.
With the engine buttoned up, I went about the business of modifying the frame and suspension. Up front, I fitted a modified set of 2001 Suzuki DRZ400 S Showa style forks. The forks were shortened by five inches, and Racetech springs and gold valves were installed to make the internals perform better. In the back of the bike, I went about reworking the frame to help get rid of the stance issue this frame has. To my eye the stock Honda Silverwing sits on its butt too much. I swept the tail section of the frame up 10 degrees and fabricated a new subframe to help get the bike to stand up better. I also lowered the gas tank mounts to flatten out the line that runs from the front to the rear of the bike along the tank seat and tail. The rear suspension was also upgraded using a rear shock from a CBR990rr which gives the suspension an additional 10mm in eye to eye shock length and shock stroke. That translates into a 1.5 inch rise in the tail height over stock. I fabricated a mount for the external reservoir on this shock that tucks in behind the engine and in front of the rear shock. Lastly, I installed a new Racetech spring on the rear shock.
Engine checked off, frame set up to sit and ride more aggressively, I moved on to getting the bike to stop better. Up front the modification was easy since the Suzuki forks already had a supermoto style rotor and dual piston brake caliper that are easily fitted. The front wheel is built from a DRZ hub and a vintage NOS Hallman racing/Sun aluminum 2.75 x 17 rim laced with Buchanan’s spokes with a Shinko E705 120/70/17 mounted for better handling. The rear is a bit more complex. To get a spoked wheel and the disc brake on the rear, I used the well known 1976-1978 Honda Goldwing rear hub mod. The drive side face of the hub was machined down to fit properly, and I fabricated a bracket that rides on the axle to carry one of the dual piston brake calipers that were originally used on the front of the Honda GL500 with an over/under linkage to provide support and stability under load. The rear disc was drilled and cleaned. The rear wheel is laced up with another vintage NOS Hallman racing/Sun 2.75 x 17 inch aluminum rim using Buchanan’s spokes with a Shinko E705 130/90/17 mounted up.
Finally, I set about styling the bike with a tracker style number plate up front, custom CNC tank badges to go on the CX tank and a custom aluminum rear battery cover with a modified vintage Japanese fog light as the brake light. All the tins were painted using a combination of HOK tangerine candy and apple red for the base color. The tins were then embellished with hand applied White gold leaf and burnt orange pinstripes and graphics I designed by my friend Sean Starr at Starr Studios. The bike was rewired using a complete Motogadget electronics array, LED lighting all the way around, and a custom fabricated aluminum headlight surround for the 7 inch LED headlight that sits offset, another nod to the asymmetry of the bike.
What is in a name? SO, the “supermoto” comes from the fork and 17 inch front and rear wheels. “Scrambler” comes from the basic high pipe design of the exhaust and the dual sports tires. “Stein” comes from, well, the mismatched parts all being made to work in harmony. The result is something that is part dirt bike, part urban scrambler, part street tracker, part cafe, and 100% fun.
Where we started…
Our plan was to take this bullet-proof Honda GL-500 and turn it into a “supermotoscrambler”. Come back to see more as we combine some nice bits on this build. A few of things in store are the a drz 400 front end, vintage 17inch wheels front & rear, modified rear disc brakes & custom vintage high pipe exhaust.
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