First Crankshafts and Test Rides
My first offset crankshaft Triumph was completed and on the road in the summer of 1999. This is a custom bike with a Yamaha RZ500 front end, Honda 750 front wheel, Nikasil 750cc barrels, a belt drive, many custom titanium and aluminum parts to reduce weight, a custom fiberglass seat and a 1999 Suzuki Katana tail light which has to be the most sexy tail light shape ever made.
The custom exhaust system and so-called muffler was made by Hindle back at a time when they would do custom one-off work. A Tony Hayward belt drive helps make the bike as smooth as possible along with a balanced clutch. Note how the Trophy-style pipes go inside the frame making the motorcycle narrower. Honda GL1000 instruments are used with the front wheel speedo drive and the tachometer was the same 2:1 ratio as a stock Triumph tachometer.
1970 Triumph Trophy with 750cc Nikasil barrels and single carb
With flangeless alloy wheels and other modifications this bike weighs less than 320 pounds dry. The fairing is from a 1981 Yamaha Seca 550; I removed the bubbles on each side where the horns normally site. The bike handles like a light 250 but with the fairing can cruise at an average of 140 klics (90 mph) until you run low on gas. That’s a trip on the 401 highway from Toronto to Belleville on a small 2-1/2 galloon Triumph tank.
This bike is loud reminding me of the sound of open exhaust V8 engines at the long-gone Pinecrest Speedway in suburban Toronto I named the bike Pinecrest after that infamous place.
I have run this bike, as built, for 20 years. Over those years of regular riding I have only lost one bolt (a head steady mount) and cracked the fiberglass seat (two-up riding on a café-style seat).
The first ride was a shock. I could hear the bike but it wound up quickly like a Japanese four and was as smooth. This was only on a local street so it took patience, and a long break-in period, before I got on the highway. The bike remained as smooth as an air-head BMW until about 4500 rpm. At that point vibration sets in but still less, at that speed, then a typical British twin. I was to later learn that the 66% balance factor I used was more suitable for riding below 4500 rpm. It’s still a great bike but could be better.
BSA & Triumph flywheel options
This first crank was an important learning experience both on how to build and in the best balance factor to use. I used the stock flywheel and quickly learned it was easier to machine my own. This saved my huge amounts of money with welding and balancing. Originally I made cranks using two separate cranks that were sawn, machined then and welded together.
I later learned how to saw a single crank apart and use a spacer for oil galleries and weld it all together. The welded crank was then machined to slip on a new flywheel, a ring that is 5/8” wide and 6” in diameter to fit the crank the same way a stock crankshaft was fit except that it is welded in place rather than bolted in place.
The performance was also notable.
After carefully breaking the engine in, over 1500 kilometres, I took the bike to the June 1999 CVMG Annual Rally. On the road run I found I was keeping up with, and accelerating as fast as Norton Commando 850s with this first bike. With the second bike, a Triumph 650, with the lighter machined flywheel, I found it could accelerate at the same rate as the 750 but this bike was smoother right up to red line with its 50% balance factor. This bike has the same Megacycle camshaft profile as the 750 but uses the stock chain primary drive.
I built the first ignition system for the 750 using two Boyer-Bransden ignition systems with a modified stator using 4 pickups. Each pair of pick-ups is connect to a single coil and one spark plug. With two ignition system ‘black boxes’ a fully charged battery is mandatory. I converted this to a single pickup system with a modified rotor but still think the dual ignition system is better in spite of it being harder to start. Both bikes now run TriSpark ignition systems which provide a stronger spark and the bikes are easier to start even if the battery charge is low.