Desert Rattler: 70s-Style Two-Stroke Scrambler from Utopeia Moto…
Back in 1960, Harley-Davidson bought a controlling interest in Italian firm Aermacchi, a former aircraft manufacturer that turned to producing motorcycles after World War II. The Italian connection would yield a range of smaller-displacement bikes to rival the lightweight machines coming out of Japan.
By the late 60s, H-D wanted a small-bore two-stroke trailbike (“desert rat”) to compete with the likes of Kawasaki, Yamaha, and even Hodaka, who’d begun selling 10,000 bikes a year. They had Aermacchi sleeve down the Rapido 125cc to create the Harley-Davidson Baja 100, then enlisted some of the fastest SoCal desert racers to campaign the bike, including Bruce Ogilvie and the Roeseler boys.
“As you would expect, Baja 100s were soon dominating the trailbike class and selling like hot cakes.” –MXA
A Baja 100 not only placed first in class at the 1971 Baja 1000, but took home 8 of the top 10 positions! Still, the Baja was never a great seller, as a massive influx of Japanese off-roaders proved cheaper and better straight out of the box. Over the years, Harley has tried several times to reenter the dirt / scrambler / adventure bike market, most recently with the Pan American ADV bike.
In light of that, our friend Chris Tope of Utopeia Moto — known for incredible, highly-detailed two-stroke scrambler builds like his Wassell Mudlark “Ice Pick” or Hodaka Ace 100 — decided to build his first-ever custom Harley, a ’73 Baja 100 that would answer the question What If?
“My design concept was to make what I would think would be the original HD Pan America of its time (in the 70’s)… The color scheme I chose is what I would’ve wanted if Harley asked me how the Baja Harley should look.”
As with any Utopeia Moto build, the detail work on this machine is simply unreal. Starting with the frame, Chris detabbed the stock tubing, cleaned and reinforced the factory welds, and fabricated a rear luggage rack before having everything powder-coated a gorgeous Prismatic Whiskey Bronze.
That dark bronze hue matches one of the stripes on the fuel tank, which has a sandy look but remains smooth to the touch and even bears the subtle mirage of an oasis in the striping — with paintwork courtesy of one of the best in the business, Kacey Elkins of Krossover Customs. The colors themselves remind of an early Toyota 4×4 truck, which is no coincidence:
“The tank still pays homage to the original Aermacchi Harley-Davidson Baja 100 but with a Utopeia Moto Company twist — a Baja (Boho) 70’s Toyota style.” -Chris
The engine has been rebuilt with a rare Harley-Davidson 125cc hop-up kit, and other period rarities include the chrome Webco racing bars and dual spark plug holder for swapping out fouled plugs on the trail — always a risk on a vintage two-stroke.
Chris is known for using unexpected materials in his builds, and “The Mojavian” is no exception. The one-off front number plate is made from Jerusalem olivewood, inlaid with the number 5 in copper epoxy resin. The same material is also used for the luggage rack slats.
The grips are made from a material we’d never even heard of: Australian Banksia pods — a type of fire-resistant pine cone from southeast Australia!
Of course, the bike wouldn’t be complete without a hobo coin or two — something of a Utopeia Moto trademark. The CNC bar ends — courtesy of the late, great Chuck Atkinson of Speed of Cheese Racing — are inlaid with a pair of 1877 copper pennies hand-engraved with tribal skulls.
The steering head bears a 1921 Liberty dollar engraved with a rattlesnake coiled through the bared teeth of a human skull — perfect for this desert-inspired scrambler!
And did we mention the valve stem caps? Yes, those are real rattlesnake rattles!
Dane Utech of Chicago’s Plzbeseated stitched up the brown suede saddle, as well as a surprise in the same material…
“There is, I’m coining this, a ‘Tool Taco,’ underneath the luggage rack to hold spare tools, parts, and extra piston rings.” -Chris
The bike is running a Dellorto carb, high-performance ignition, and a cold-rolled expansion chamber from Jemco Exhaust Systems. Combined with the 125cc hop-up kit, this 198-lb two-stroker is loud, proud, and double handfuls of raucous fun.
“If the motor doesn’t knock you off, the exhaust will either burn the shit out of you or blow out your ear drums.” -Chris
Chris has transformed this 51-year-old Baja 100 from desert rat to desert rattler. The fabrication, unexpected materials, and thoughtful dedication to (unique) details are what you might expect to see in a 70s-inspired Panhead or Shovelhead chopper build, but the small-bore Aermacchi Harleys have rarely received this kind of attention. In our eyes, that makes “The Mojavian” all the more cool — the perfect custom crossover of new-wave scrambler and old-school Harley-Davidson.
If you want to see The Mojavian in the real, it will be on display this weekend at Fuel Cleveland, happening at Hale Farm & Village in Bath, Ohio. This is one of the friendliest and most fun shows of the year. So if you’re within striking distance, do yourself a favor and check out this scintillating desert rattler — just watch for this ear-busting bite of that exhaust!
Below is our full-length interview with Chris, along with a complete build sheet. Photography credits go to Chris himself for the outdoor shots and our man Kody Melton for the indoor shots from the 2024 Handbuilt Show, where “The Mojavian” first broke cover.
“The Mojavian” Baja 100: Builder Interview
• Please tell us a bit about yourself, your history with motorcycles, and your workshop.
Although I would love to say bike building is my full time job, it is a hobby that has grown into a passion. I am a full time Biologist and Compliance Monitor working with energy companies all over the US. Due to the nature of my job, I move every year or so.
I built my first motorcycle (Yamaha QT50) when I was 15 years old. From then on I was hooked on bringing motorcycles back from the dead and adding my twist. I have lived in 12 states in the last 19 years. I have never had any formal motorcycle training; I just owned and rode motorcycles when I was younger and slowly started building. I completed my first custom build, the CB450 Bomber while on a project in California and I am currently in West Virginia building bikes.
• What’s the make, model, and year of the donor bike?
1973 Aermacchi Harley-Davidson Baja 100, “The Mojavian.”
• Why was this bike built?
It was a commission from Michael Blackwell, who was referred to me by a buddy of mine. Blackwell pretty much told me you have “carte blanche” on this build. So I told him I’ve been wanting to build a Harley Baja 100 for many years and if he’s alright with it, then that’s the bike.
As you know from my past builds, I’m a sucker for two-stroke motors. I’ve also never built a custom Harley-Davidson (one that had my style), only just repaired them… This project was going to be a blast.
• What was the design concept and what influenced the build?
My design concept was to make what I would think would be the original HD Pan America of its time (in the 70’s). I wanted to do some retro natural colors and incorporate a desert feel. That’s why the tank still pays homage to the original Aermacchi Harley-Davidson Baja 100 but with a Utopeia Moto Company twist — a Baja (Boho) 70’s Toyota style.
The color scheme I chose is what I would’ve wanted if Harley asked me how the Baja Harley should look. The tank also has a sand texture that is smooth to the touch. Also check out the hidden desert Mirage in the side striping.
• What custom work was done to the bike?
Every nook and cranny have been either modified or fabricated (see Bike Specs). I have three custom hobo coins on the build. Two are 1877 pennies that have been hobo-engraved as a tribal skull.
Also, there’s a 1921 Liberty Dollar that have been hobo-engraved as a rattlesnake coiled around a skull due to this bike being built as a desert style.
I have also incorporated custom valve stems that have rattlesnake rattles.
The bike has a unique retro Webco racing handlebar with Joker Machine levers.
I modified the chassis by de-tabbing the frame, re-enforcing the welds, cleaning up the existing welding, and fabricating a custom built-in luggage rack inlaid with Jerusalem Olivewood. I powder-coated the frame a beautiful Prismatic Whiskey Bronze color to match one of the fuel tank stripes.
The bike also features a rare and original Harley-Davidson 125cc hop-up kit instead of the original 100cc. It also has multiple holes milled out of the motor head to add surface area for cooling and reduce weight.
The motor covers have been fully polished. I also attached to the frame a very rare Webco (matching frame colored) dual spark plug holder for that quick change while out racing in the desert.
The grips are piece of art alone, made from Australian Banksia pods inlaid with copper, and the bars ends housing an 1877 Hobo Skull copper penny.
I made a custom one-off racing plate made from Jerusalem Olivewood and inlaid with a copper epoxy resin.
The seat has been fully modified starting with slimming out the seat pan to follow the contours of the fuel tank width. The seat has memory foam for the cushion and wrapped in a beautiful brown suede leather. 
There is also a custom, I’m coining this, “Tool Taco,” underneath the luggage rack to hold spare tools, parts, and extra piston rings.
There’s a one-off cold-rolled steel expansion chamber exhaust for blowing out your and nearby spectators ear drums.
The wheels were powder-coated black with polished spokes and wrapped in knobby oversized Maxxis tires. The swingarm was extended by 1” to compensate for the large tires. I milled out holes on the rear sprocket for weight reduction and looks.
• Does the bike have a nickname?
The Mojavian due to its design influences from the Mojave Desert.
• Can you tell us what it’s like to ride this bike?
The bike rides like a dream. The 125cc HD hop-up kit brings unimaginable power to this lightweight 198-pound two-stroke. If the motor doesn’t knock you off, the exhaust will either burn the shit out of you or blow out your ear drums.
• Was there anything done during this build that you are particularly proud of?
I am very proud of all the one-off never to be done again custom parts: olivewood race plate, banksia pod grips, olivewood luggage rack, and amazing custom tank.
Full Build Sheet
Owner: Michael Blackwell
Build Time: 5 Months 12 days
Shop: Utopeia Moto Company Garage
Fabrication: Chris Tope
Assembly: Chris Tope
Base model: 1973 Aermacchi Harley-Davidson Baja 100
Engine size: 125 cc Piston-port 2 Stroke, restored by Chris. The bike had a 125cc hop-up kit by Harley-Davidson, which is very rare.
Carburetor: Dell’Orto
Air Filter: Modified K&N Pod
Transmission: OEM, HD 5 speed multi-plate
Exhaust: Custom handmade expansion chamber exhaust from Cold rolled steel by Jemco Exhaust Systems
Ignition: High Performance
Fuel Tank: OEM, custom painted by Krossover Customs
Frame: Custom-modified frame. De-tabbed, fabricated a built-in luggage rack incorporating custom Jerusalem Olivewood. Fabricated powder-coated swingarm that has been extended 1″,
Frame Paint: Whiskey Bronze powder-coated
Wheels: Powder-coated wheels, 21″ Front, 18″ Rear. New Buchanan spokes.
Tires: Maxxis Front and Rear
Front fork: Restored Ceriani 30mm
Shock: Custom dual shock setup by Hagon Shocks
Front Brake: Drum
Rear Brake: Drum
Rear Sprocket: Dual Modified, Fully Polished
Handlebars: Custom Webco chrome handlebars
Handgrips: Banksia Pod (Australian pine cone) inlaid with copper by Greg Madrigal, and Mark Atkinson’s CNC sleeves, CNC bar ends inlaid with 1877 copper hobo pennies
Hand Controls: Custom Joker Machine levers
Race Plate: Custom Jerusalem olivewood inlaid with number 5 copper epoxy resin
Taillight: Beware
Transmission: 5 speed
Footpegs: OEM
Blinkers: N/A
Seat: Fabricated seat pan slimmed out to follow the lines of the gas tank.
Upholstery: Brown suede leather seat and custom brown suede leather “tool taco,” stitched up by Dane Utech at Plzbeseated
Painter: Kacey Elkins at Krossover Customs
Bike Photos: Chris Tope
More Photos
Follow the Builder
Chris Tope, Utopeia Moto Company (I put the Tope in Utopia…)
Email is preferred: [email protected]
Instagram: @utopeia_moto_company
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Sweet!
Inspired build. I started riding in the early ‘70s, remember the H-D/Aermacchi’s well. A 350cc Sprint would be great fun, too. Especially love the “Tool Taco”, last bike from this period I owned had a horseshoe-shaped leather Malcolm Smith tool bag zip-tied to the frame loop behind the seat.
In 1972 I was at a desert race in Lucerne Valley, CA when a desert racing friend of mine introduced me to a young kid. My friend said he was gonna be a star and had just signed a contract with Harley which was a big deal. That young kid was sitting on a black Baja 100 that he was going to race in the Trail Bike class. His name was Larry Rosselor and he did indeed become a very big off road racing on two wheels and on four!
THAT BIKE WAS A PIECE OF JUNK WHEN NEW AND IT’S STILL A PIECE OF JUNK.
I was waiting for that!
Whilst these forums certainly exist for people to express opinions, their real value is based upon contributions. When readers/subscribers can provide detail, persuasive argument, historical facts, comparative discussion etc, then we have truly contributed, and the forum benefits and flourishes. It then becomes a place we routinely like to ‘attend’, such as an art gallery. I am therefore curious to know why it is, and continues to remain, ‘a piece of junk’.
Bellissima ho avuto il modello sst ed era uno spettacolo, questa è ancora più bella naturalmente! Moto divertentissima!
Good to see that you are using Aussie fire proof parts. LOL
The seat looks terrible. Why so flat for desert bike? Imagine how uncomfortable it would be after a 2 hr ride even on the street let alone the desert.