Flat Track History
What a lot of people don't know is, Erv did two
distinctly different engines for those flat trackers.
One was a conventional 3 fire per revolution, 120 degrees apart, as in H2R.
The other was a "tringle", with all 3 cylinders firing at the same time.
Jeff Bratton, in San Jose, Erv's home town, did all of Erv's crankshafts.
It was common to see Suzuki T20's and other 180 degree twin's crankshafts
rephased to fire both cylinders at the same time, once per revolution.
The tringle took 4 people pushing both forward...and downward, to get it started, in second gear only. Even backed up against compression, if tried in 1st gear, it'd just lock the rear wheel up and skid it as far as you cared to keep on pushing it.
Erv's triples used a conventional magneto CDI from an
H2R. The tringles used a special Krober with one fire, capable of running three
boxes and coils. It was very unreilable. Erv also had some Suzuki ignitions he
got when he worked for them after Kawasaki, that I think were single fire 3
cylinder stuff.
I've seen a lot of Suzuki T20 (X6 Hustler) twingle flat trackers. At one time,
that was the ONLY bike to do that to for small displacement flat tracing. They
used to run really stout.
There never were compression releases on those H series flat trackers, that is
why it was so hard to start the tringles.
Nixon had a problem one year with a damaged right thumb, he couldn't hold the
throttle to turn it on, so Erv wired the throttle wide open and added an easier
to use kill button. Gary would kill the ignition to back it into a corner, then,
let 'er rip. Kenny had Kel wire a second kill button for killing only the left
outside cylinder on his TZ700 tracker. This let Kenny make the bike into a 3
cylinder going into a turn, then, lit the 4th cylinder up for the straightaways.
The Yamaha TZ700/750's fire as an 180 degree offset pair of twingles, outside
cylinders fire together, then the centers, 180 degrees later, as their own
twingle.