Beeber: BMW R100GS Restomod

BMW R100GS Custom
Photo: Handbuilt Show / Revival Cycles

As Seen at Handbuilt: Urban GS Airhead from Chuck Pryor…  

The BMW R100GS was the successor to the original Gelände/Straße (German: Terrain/Street) model, the R80GS, which is widely considered the progenitor of the modern ADV bike. The R100GS incorporated improvements gleaned from the GS’s success in the world’s most grueling race, the Paris-Dakar Rally. The 980cc Bavarian beast delivered in spades.

“You learn to expect adventure, because the R100GS instills an Indiana Jones mentality in anyone who rides it. The bike begs you to go exploring, get lost, and sometimes even get in trouble…” –Cycle World, 1988

BMW R100GS Custom

Indeed, the big GS has encouraged generations of riders to blast down roads a machine of such size would seem to have little business tackling, getting owners into trouble…and out again, more often than not. Few bike have earned such a globetrotting reputation as the airhead GS, and BMW themselves have gone as far as to offer the R nineT Urban GS Bumble Bee, a nod to the iconic yellow and black ’88 GS Bumble Bee.


R NineT Urban GS Bumble Bee

Enter our new friend Chuck Pryor, a veteran motorcyclist who’s ridden in every state of the US over his 30+ years on two wheels.  Half a decade ago, he got into airheads, and now he owns a small stable of them in prime running condition.

BMW R100GS Custom

When Chuck saw BMW’s modern take on the Bumble Bee — the bike that led him to airheads in the first place — he had an idea.

“When I saw one of those in my local dealership I thought how cool it would be to build an ‘Urban GS’ but using an original Bumble Bee.”

BMW R100GS Custom

That would lead to “Beeber,” the resto-modded ’89 R100GS you see here — a bike he bought with just over 50,000 original miles. The engine is now running a Siebenrock Big Bore Kit with dual-plugged heads and a Dual Spark Wedgetail ignition, breathing through new Bing carbs and a Siebenrock exhaust with Arrow silencer. Siebenrock claims 85 hp from the kit, and Chuck says his butt dyno agrees!

BMW R100GS Custom

With the rest of the modifications, Chuck tried to use as many BMW OEM parts as possible, and nearly everything on the bike has been upgraded or replaced. The subframe was shortened and looped and the triple trees, fork tubes, wheel hubs, gauges, and more have all been replaced with new or NOS parts. The front caliper is from an R1100, and Chuck actually had a gunsmith do the Cerakote on the engine.

BMW R100GS Custom

Dustin Maybin at Maybins Concepts laid down the paint while one of his guys TIG-welded the exhaust midpipe, and the legendary Nathan Mende at Georgia’s Boxerworks was kind enough to let Chuck use a lift, some special tools, and generally pester him with questions.

BMW R100GS Custom

This is one of the cleanest R100GS examples we’ve ever seen, and it looked amazing at the 2024 Handbuilt Show.

BMW R100GS Custom
Photo: Kody Melton at Handbuilt Show 2024

Even more important is how it rides:

“It’s a BLAST to ride. For me it’s the most comfortable riding position on any of my Airheads…looks fantastic, sounds fantastic, and runs fantastic.” -Chuck

BMW R100GS Custom

Below you’ll find our entire uncut interview with Chuck, and photos credits go to David Dobson (@daviddobsonphoto) except where noted. It sounds like Chuck might be putting this bike up for sale soon, so give him a follow (@chuckpryor) if you might be interested.

BMW R100GS: Owner Interview

• Please tell us a bit about yourself, your history with motorcycles, and your workshop.

Been riding motorcycles for over 30 years including every state in the US… first street bike I bought was a 79 Honda CX500 back in the early 80’s… from there went on to ride V-Twins until 2012 where I bought my first new BMW (K1600GTL). Since then most bikes in my garage are BMWs. I really started getting into airheads about 5 years ago when I saw a friend with an ’88 GS Bumble Bee.

BMW R100GS Custom

Current lineup includes…

  • 1958 R60 (29K org miles)
  • 1983 R100 Standard (4300 org miles)
  • 1983 R100RT (11,000 org miles)
  • 1987 R80 (3500 org miles)
  • 1989 GS (bike we are discussing) had 50K org miles now with 350 after build
  • 2016 R1200RT (3600 org miles)
  • 2017 R1200GSA I bought new now with 67,000 miles
  • 2022 HD Road King I bought new now with 9K miles
  • Two low-mile Airheads I bought from Org owners and other from 2nd owner who had it the past 25 years. They are all riders but kept in pristine running and looking condition.
• What’s the make, model, and year of the donor bike?

1989 R100GS. The bike had 50K original miles on it and was well used.

BMW R100GS Custom

• Why was this bike built?

This is a personal bike…

BMW R100GS Custom

• What was the design concept and what influenced the build?

The build was inspired by the 2021 R nineT Urban GS Bumble Bee. When I saw one of those in my local dealership I thought how cool it would be to build an “Urban GS” but using an original Bumble Bee. I prefer the 88-89 styling of GS Airheads and searched for the donor bike. It came from Zac at Max BMW and was a running bike. It needed love but was running.

BMW R100GS Custom

• What custom work was done to the bike?

I worked REALLY hard to keep the bike as OEM based as I could while still making it custom. For example, ALL of the wiring is OEM, all of the NEW parts are OEM, and even though it’s “custom” with a few simple parts (most of which I have) it can be returned to stock. The subframe had already been shortened when I bought it but fabricated the “loop” on the rear subframe to hold the license plate.

BMW R100GS Custom

While sourcing parts though I found a NEW OLD STOCK subframe and secured it just to potentially return it as it came off the assemble line. I replaced literally EVERYTHING on this bike with NEW OEM parts. The upper/lower triple tree, the fork tubes, wheel hubs, carbs (yes, even new Bing carbs).

BMW R100GS Custom

The engine got a Siebenrock Big Bore Kit which REALLY wakes these R100 motors up. I dual plugged the heads and installed the Dual Spark Wedgetail ignition.

Literally every electronic components is new as well. Even the speedometer, volt meter, and tach are NOS OEM parts that I was able to source.


• Does the bike have a nickname?

Yes, Beeber.

BMW R100GS Custom

• Any idea of horsepower, weight, and/or performance numbers?

I’ve not had this bike on a dyno but Siebenrock claims up to 85HP on the R100. Based on the “butt dyno” I’d say the claims are valid. The cam really starts to light up at 5K RPM and keeps going from there.

BMW R100GS Custom

• Can you tell us what it’s like to ride this bike?

It’s a BLAST to ride. For me it’s the most comfortable riding position on any of my Airheads…looks fantastic, sounds fantastic, and runs fantastic.

BMW R100GS Custom

• Was there anything done during this build that you are particularly proud of?

Of all the things the way the exhaust turned out. The header and Y-Pipe are from Siebenrock but when I mocked up the muffler it just didn’t look right for the build so I started searching. I came across some “Arrow” products and found one that I though could work…ironically, it just happened to be made for a 2021 R nineT Urban GS!! It seemed like fate…

BMW R100GS Custom

I thought it may sound too obnoxious but I took a chance and as it turns out it sounds FANTASTIC and not too loud at all. I think it really sets off the profile of the bike.

• Is there anyone you’d like to thank?

Yes, I could not have done this build without the help of some key folks. Dustin Maybin, at Maybins Concepts. He did the paint (second bike I’ve had him paint) and he’s just FANTASTIC. One of his guys Bobby did the stainless TIG welding on the exhaust mid-pipe and it’s amazing. Dustin is an uber talented fabricator/machinist and the bike would not be what it is without him.

Also need to thank Nathan at Boxerworks in Georgia. He let me pick his brain, use some special tools, a lift, and generally pester him during the build. And have to thank from friend Lee Dickinson for some electronic guidance and tuning help.

Full Gallery

Follow the Builder

Instagram: @chuckpryor
Photo Credit: David Dobson (@daviddobsonphoto)

One Comment

  1. steveofthenw

    Problem with that bike is that it’s just too nice. It would hurt my heart to take it off road and beat the tar out of it like a proper ADV. That thing is beautiful.

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