Big Dog Mastiff




Make Model.

Big Dog Mastiff




Four stroke, 45° V-Twin, OHV, 2 valves per cylinder.


1916 cc / 117 cu-in
Bore x Stroke 104.8 x 111.1 mm / 4 x 4 ⅜"
Compression Ratio 9.6:1
Cooling System Air cooled


S&S carburetor


Electronic single fire


270 cca




6 Speed

Final Drive

Frame Standard downtube,  4" Backbone



Front Suspension

Ĝ41 mm Telescopic fork

Rear Suspension

Hidden shocks

Front Brakes

Single disc PM, 4 piston caliper, differential bore

Rear Brakes

Single disc PM, 4 piston caliper

Front Tyre

MH120/70-21, Avon

Rear Tyre

250/40 -18, Avon
Wheelbase 1842 mm / 72.5 in
Ground Clearance 114 mm / 4.5 in
Seat Height 648 mm  /  25.5 in

Dry Weight

291 kg  /  641 lbs

Fuel Capacity 

17.4 L / 4.5 US gal

Oil  Capacity 

2.8 L / 3.0 US qt

When Big Dog Motorcycles CEO Sheldon Coleman and President Nick Messer unveiled the 2006 line-up of motorcycles to members of the motorcycle press recently both predicted the 2006 Mastiff would be one of the company's best selling bikes for that model year. They explained that market response dried up for the Mastiff in 2005 so the bike needed a redesign.

The 2006 Mastiff has been stretched and lowered considerably: the wheelbase is 5 inches longer; the frame has been raked an additional 2 inches, and the seat has been dropped by 1.25 inches to a low 24.25 inches. There's a one-piece stretched tank, a new feature on all the 2006 models.

Because of all this elongation going on, I wondered how comfortable I would feel riding with my arms and legs outstretched in such a deliberate U-shaped position. I've ridden these kinds of custom bikes before. I understand what company executives are trying to achieve with this new design. Their research shows that their customer base (25- to 40-year-old males) desires motorcycles with a long, low profile.

The pullback risers position the handlebars right in front of the rider. I didn't have to lean forward too much to reach them. For me to be completely comfortable though, I would have liked just a little more bend in my elbows. Same for my legs. The forward controls are close enough for me to shift gears and brake just fine, but more bend in my knees would have allowed me to move and stretch my legs while riding without taking my feet off the controls. I'm 5 feet 7 inches with boots. It's clear that these long, lean machines fit average-height to tall individuals. Big Dog executives are aware of that so an aftermarket seat is available that pushes the rider closer to the controls.

The heart of the machine is a 117 cubic inch engine supplied by S&S Cycles and assembled in the Big Dog Motorcycles factory. That's 1916cc's of power and torque. The BDM Balance Drive supplied by Baker Drivetrain was the best thing to happen to Big Dog Motorcycles a few years ago. It brings the final drive to the right side of the motorcycle allowing for better balance and rideability on these fat tire bikes.

The 6-speed transmission has been refined for 2006 making shifting a breeze and finding neutral even easier. I liked how the bike started right up when I thumbed the starter button. Earlier S&S motors could be testy. During my entire afternoon ride, the bike delivered smooth, consistent power to the pavement.

The fat tire on the rear is an Avon 250/40-18; the front is an Avon MH120/70-21. Both are wrapped around forged 12-spoke shiny aluminum wheels. Handling a motorcycle with such a big rear tire isn't as hard as you might think. I remember riding earlier models from Big Dog Motorcycles that were a chore to steer. Either I'm getting used to that big tire feeling or Big Dog is dialing in the configuration better.

With all that power and rubber underneath me, I expected some decent stopping power. The Mastiff didn't fail me. The 2-piece Brembo vented floating rotors are the kind used in racing applications so they're very strong. The calipers have four pistons and are supplied by Performance Machine.

The Mastiff, as well as all the Big Dog's, are stunning visually. The press materials included a 28-page paint booklet outlining the different paint jobs available. Five new base colors and 17 new graphic designs were added to the already long list of paint options. Dollarwise, the 2006 Mastiff is right in the middle of the price spread for all the Dogs at $28,500. Seems like a lot of money to some, but for customers already dabbling in this exotic custom bike market, they know that's a pretty fair price. You'd most likely pay a lot more for a builder to custom build a bike using the same high-end parts. Remember, Big Dog Motorcycles is a mass production manufacturer. Their price has to appeal to the "broader" audience.