A Google search will bring up several photos. I'd post a few more, but I've run out of available time today after reviewing and updating the following
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short history document which was originally written in about 2004/2005:
Ed
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The Hodaka Bullfrog
A short History
To be accurate, it must be noted the Bullfrog observed trials motorcycles were not the result of an “OFFICIAL” development project at PABATCO. They were created out of the interests and passions of several of the enthusiasts who worked at PABATCO. Of course there WAS critical PABATCO/Hodaka support on some items. There were two classes of PABATCO/Hodaka support for the Bullfrogs:
Knowing (Official)
&
Un-knowing (un-official)
. . . we’ll leave it at that, OK?
During the late ‘60’s and early ‘70’s Observed Trials was a popular and growing aspect of motorcycle sport. Traditional 4-stroke “thumpers” had already fallen from favor for trials competition. In fact the first generation of “purpose-built” trials two-strokes from Cotton and Greeves were starting to be replaced by second generation machines from Bultaco, Montesa and OSSA. As might be expected, several British developers kept “pushing the envelope”, trying to find the optimum balance of light weight, precision handling and power. Several makers concentrated on 125cc engines to cut weight and machine size to a minimum (Saracen, Dalesman, Wassel, etc.)
The Saracen 125 was an excellent example of the strengths – and weaknesses – of the “smaller & lighter is better” concept using off-the-shelf components. The Saracen had a single front down tube frame custom designed to use REH hubs and forks and a Sachs engine. It was light and pretty effective, but the suspension was just “so, so” and the engine certainly wasn’t optimized for observed trials. Sachs apparently wasn’t interested in building a low production 125cc trials engine with some extra flywheel weight – and warranty considerations probably prevented the Saracen folks from adding extra flywheel weight. Even with those problems, a Saracen was ridden to 9th place in the 1971 Scottish Six Days Trial. (I have subsequently learned that the Saracen was produced as a British woods riding enduro machine and “play” MX bike and the trials bike was the same machine with a different exhaust and no lights. Steering geometry was not optimized for Observed Trials.)
Harry Taylor built the first PABATCO/Hodaka “works” trials machine sometime prior to 1971. In the fall of 1971 Leon Wilbanks rode Harry’s machine in the Canadian National Trials as a member of the Pacific Northwest Trials Association (PNTA) Club Team. Other members of the team were Ed Chesnut and Mick Oliver, both mounted on Saracen 125’s. The all 125 team won the team competition that year. Wanting to build a “one off” and impressed with handling of the Saracen frames, Leon brain-stormed the creation of the Bullfrog featured in the February 1973 issue of Cycle World (see copy of article – Note that the project would not have been possible without Curt Alexander’s skills). Sometime in 1972, Leon finished the first Bullfrog. In a way, it was a skunk-works prototype. Leon worked every angle, gathering parts from any source which would result in a “primo” machine. Saracen frame, Akront alloy rims, snowmobile disc brakes front and rear, Cotton tank and a “project” Hodaka trials engine. (A more complete description is available in the attached article.)
The success of the “grandpappy Bullfrog” gave several of the rest of us at PABATCO a severe case of the, “I gotta have one of those!” willies. A low budget, sweat intensive plan came together. 4 of us would purchase the materials needed to build 5 Bullfrog frames with dual down tubes and Hodaka engine mounts (Chuck Swanson, Jim Gentry, Ed Chesnut and Weil Muxlow – “Mux” did technical illustrations for PABATCO from time to time). Curt Alexander would cut, bend, jig and weld the 5 frames – and keep one when he got through. These were the “production” Bullfrogs, but there was no PABATCO involvement on these units – well, other than the time we managed to sneak to get the frames done (remember the “un-knowing” support?). Of these frames, only Curt’s and Ed’s ended up on wheels. (Subsequent to this write up, Chuck got his going with a 100cc Fuji engine.) Curt’s bike was numbered 001 on the steering head and Ed’s was not numbered.
(NOTE: In 2003, Eric Smith brought a “Bullfrog” frame to Hodaka Days for inspection by Ed Chesnut. There is no doubt that Eric has Curt’s machine – and Eric has since reassembled the machine to riding condition.)
Over the years Ed’s machine has received some changes, the rear fender originally installed was mis-placed and whatever was available was used to replace it. (The original rear fender has since been found.) In addition, the interior of the airbox and the connection between the airbox and carburetor was re-worked in 2003. (Note that Ed’s Bullfrog was assembled while Ed was making the transition from photographer/writer to endurance rider and Service Dept. whiz kid AND on the “after beer budget” of a 24 year old single male – as a result some things REALLY needed re-work!) Other than replacing the throttle cable with a NOS replacement and a set of NOS Doherty grips, the machine is EXACTLY the same machine it was in 1973. In the fall of 1973 Ed and his Bullfrog were members of the Pacific Northwest Trials Association (PNTA) club team which won the team competition at the Canadian National Trials (with Leon Wilbanks and Mick Oliver).
Possible future improvements/modifications/experiments:
- New alloy fenders (completed, Winter/Spring 2004)
- Build and install skid plate (completed, Fall 2003)
- Completely new airbox/side panel system (completed, Winter/Spring 2004)
- Custom painted Bultaco Pursang fuel tank OR . . .
- Finish up the under-seat fuel tank system originally started in 1973 OR . . .
- Find, obtain and install a Cotton tank (completed, Winter/Spring 2004)
- Bushing for front end of rear brake stay
- Wombat (iron cylinder)-reeded OR . . .
- Wombat (03) Alumiferric cylinder-reeded
- Super Combat close ratio transmission
- Radial competition trials tires (installed in 2003 – WOW!)
Modifications planned for Spring 2005 include:
- Replace Yamaha(?) triple clamps (how did those get on there?) with stock Hodaka clamps to reduce trail and make steering more neutral
- Install adapters or replace shocks-changing from 12 7/8” to 14 ½” shocks to reduce rake and trail to make steering more neutral - these two changes will bring the front end geometry VERY close to a modern Montesa – testing has already shown the mods will improve steering (completed Jan. 2005-major improvement to steering)
- Relocate foot pegs (relocation required after installation of taller shocks to keep rider/machine center of gravity from being too high) – (completed)
- Detailed lightening work on shock bolts, skid plate mounts, etc. to reduce weight.
- Other???? – possibly a new exhaust system with 1.5” dia. header to improve low RPM performance (I already have the “U” bends to build it).
BULLFROG SPECIFICATIONS
Ed’s machine
Engine: Model 94 Wombat with reed valved Model 95 Combat Wombat “Alumiferric” cylinder & head. 24mm Mikuni carburetor. Standard flywheel magneto/point ignition. Custom flywheel weight added to magneto side (3.4 pounds) – uses flywheel puller threads for attachment. Stock Wombat transmission. Wombat clutch also has extra weight (approx. 2 pounds). Final drive sprockets 12 or 13/64 (5.33:1 or 4.92:1) – 12 is preferred – but due to the lack of chain adjustment, a 13 tooth is in use.
Frame: Custom designed Bullfrog. Mild steel, dual front down-tube. (Saracen 125 Trials bike provided guidance for steering geometry, wheelbase, etc.)
(Knowledge gained in 2004 suggests that the Saracen steering geometry was much like the Sammy Miller inspired early 70’s Bultaco Sherpa T with lots of trail.)
Wheelbase: 51.75”
Weight (lbs-no fuel – digital scale): F/R/Total 74.4/92.2/166.6
- with 1 gallon of fuel (before 2004 rebuild) 77.4/94.6/172
- w/ 1 gal. fuel AFTER 2004 rebuild 77.4/94.8/172.2
Wheels/brakes: Stock Hodaka with extended brake actuation arms, light alloy rims.
Forks: Modified Wombat – no topping springs, full length main springs – 6.125” travel. Resonator tuning tips.
Rear Shocks: Girling 12 7/8” eye-to-eye/4” travel @ axle. Shock mount adapters raised the rear end as though 14 ½” shocks had been installed – completed in Jan. 2005.
Rake: 28 degrees (original) – will change to 25.5 degrees in 2005 (completed)
Trail: 4.9” - will change to 3.5” in 2005 (completed – and MUCH better!)
Other: 1.75” diameter header pipe, Sammy Miller alloy muffler, Sammy Miller(?) chain tensioner, Renthal handle bars, Gaylen Springer nylon throttle cable, Doherty grips, Modified Hodaka Ace 90 front fender mount, hand hammered aluminum seat base, hand formed chain guard, accessory steel case protector, sheet ABS airbox assy. with oiled foam filter (fiber-glass and aluminum air box has replaced the heavy ABS unit), 1.5 gallon plastic fuel tank (plastic tank has been replaced by a Cotton tank).
A NOTE REGARDING THE ORIGINAL BULLFROG
Leon gave the original Bullfrog to Paul Stannard of Strictly Hodaka to assure that it had a home which would value and respect its history. Paul is restoring the bike to operating condition (Completed. The 175cc Bullfrog was on display @ Hodaka Days 2004.)
Victor