Briggsand Stratton

Another Briggs and Stratton Bobber from… Bob.


The build sheet:

Specifications For Black Briggs Bobber
Frame—————————Probably nos aftermarket hardtail from the 60s
Wheelbase———————58 in.
Rims—————————–18 x 2.15
Tires—————————–18 x 4
Hubs—————————–Honda 350
Brakes————————–Drum
Swept Area——————–56.5 sq. in.
Brakes Loaded—————-8.8 lbs. per sq. in.
Curb Weight——————-300 lbs. / 200 lb. rider – 500lbs.
Fork—————————–Homemade
Rake—————————-25 degrees
Trail—————————–3 in.
Suspension——————–Leaf spring over leading rocker
Floorboards——————-24 in. Wide and 8 in. clearance
Lean—————————-35 degrees
Ground Clearance———–6 in.
Axle to Ground—————13 in.
Crankshaft to Ground——-11.75 in.
Handlebars——————–Lowrise buckhorns 31 in. wide with 5 in. rise on 3.5 in. dogbone risers
Grips—————————Anderson style
Engine————————-V twin ohv Briggs and Stratton
Displacement—————–34.75 cu. in. / 570 cu. cent.
Bore—————————-2.83
Stroke————————–2.76
HP——————————18 @ 3600 rpm
Torque————————-30 ft. lbs. @ 2400 rpm
Exhaust————————two into one header 1.75 in. auto
Drive Train——————–comet ind torque converter
Drive Clutch——————-44 c magnum
TQ Overall Ratio————-2.43 to 1
Final Drive———————428 chain sprockets/ 15t into 60t for 4 to 1 ratio
Speed————————–70 mph @ 3600 rpm
Frame Geometry————-Cloned from Indian 101 Scout
Steering Geometry———–Cloned from Indian 101 Scout

Update: Worlds Fastest Briggs and Stratton Custom Motorcycle! Seriously.


Updated with more pics!  Thanks again Bob!  And once again Nice Job!  I REALLY like these sorts of builds.  Very Creative.

Bob Decker sent in some pics and links to this really cool custom Briggs and Stratton powered custom but this is the only one I could get to that was big enought to use. I’ll update the post if Bob can get me some more. I love this concept. I’ve looked at the big Briggs engines and before and thought that they were plenty powerful enough for a motorcycle. 35 HP and 52 ft lb of torque ain’t bad!  Guess I was right! Thanks Bob!

Here Is the Build Sheet he sent me with it:

Frame——————————————————————Homemade designed from scratch

Wheelbase————————————————————-59.5 in.

Rims——————————————————————–18 x 2.15

Tires——————————————————————–18 x 4.5

Hubs——————————————————————-Honda 350

Brakes—————————————————————–Drum

Swept Area———————————————————–56.5 sq. in.

Brakes Loaded——————————————————-10 lb. per sq. in.

Curb Weight———————————————————-368 lb./200 lb. rider – 568 lb.

Weight Distribution—————————————————Front – 169 lb. / 46%

Raer – 199 lb. / 54%

Fork——————————————————————-Homemade

Rake——————————————————————-26 degrees

Trail——————————————————————-33.3 in.

Suspension———————————————————–Leaf spring over leading rocker

Front rocker lift ratio————————————————2.6

Floorboards———————————————————-24 in. wide and 8 in. clearance

Lean——————————————————————-35 degrees

Ground clearance—————————————————-5 in

Axle to ground——————————————————-13.5 in.

Crankshaft to ground———————————————–11.125 in.

Handlebars———————————————————–Lowrise buckhorns 31 in. wide with 5 in. rise on 3.5 in. dogbone risers

Grips——————————————————————Ivory from a dead woolly mammoth

Engine—————————————————————-V twin ohv Briggs and Stratton

Commencer———————————————————–Electric

Displacement———————————————————-60.6 cu. in. / 993 cu. cm.

Bore——————————————————————-3.36

Stroke—————————————————————-3.42

HP———————————————————————35@3600rpm

Torque—————————————————————-52.2 ft. lb. @2400 rpm

Exhaust—————————————————————Dual

Drive Train————————————————————Comet torque converter

Driver Clutch———————————————————-94c duster

Overdrive————————————————————–128%

TQ Overall ratio——————————————————-3.49 to 1

Highest gear———————————————————–2.8 to 1

Low gear—————————————————————9.8 to 1

Final drive————————————————————–50 pitch sprockets / 15t into 54t for 3.6 to 1 ratio

Speed——————————————————————106.39@3730 rpm