Suzuki GT750 Phat Trakka Drag Race fun | |||||||
This bike was conceived and
built as a mild fun street bike. There was never any intention to
race it in any form whatsoever. I made the mistake of encouraging
a fellow GT750 owner in his race efforts with his full on GT750 Drag
race bike, and I was seduced into taking
it to the drag strip for a fun run in the sun. Pipes were changed
to a set of Jemcos and that was as far as changes went. The bike
was still high and wide - the polar opposite of a drag race bike.
By
2015, the forks were replaced with a spare set that were lowered a
little - maybe 3 inches and bars were changed first with drag bars which
were incredibly uncomfortable and then with a set of clubman's bars
which are marginally less uncomfortable. Still with full lights horn,
charging system etc but now fitted with CO2 cylinder in the tail and air
shift/ignition kill system that usually reduced shifting issues.
Carbs
now had SteelDragon velocity stacks which looke wicked but didn't make
much difference to ET or MPH, but looks count. Launch
was still closer to a supertanker than a rocket launch but getting there
- slowly.
Nice new Vanson
leathers in 2016 make race days more comfortable, but they don't
make the bike any faster. By 2017, another
poofteenth had been shaved off MPH was down a few with the different
transmission. Carbs now had custom made shorty bellmouths, to
try to get a few more HP at the very peak of the rev range. Forks
were shortened a little more, and shorter rear shocks were added
along with a swingarm pinched off a late model GT750B. It
looks almost like a GS750, which was in production at the same time,
but with a brake torque arm mount for the old drum brake. Before the race, the
motor was stripped and inspected and all was OK but some of the gear
dogs were worn, so the whole transmission was replaced with a
suitably modified GS750 with higher first and lower top gears. The
higher first gear was better for the 1-2 shift but made it a little
harder to launch and the lower top gear set killed top end by
3-4mph. While it was apart, the ports were cleaned up a little but
still left as a very streetable set up. Unfortunately the
CO2 high pressure regulator had decided it was hot and bothered and
didn't want to play nice. It caused a lot of missed shifts and
much frustration. That will be added to the "to do" list for 2018 For 2018, the carbs
have been replaced with a set of 72-3 model slide type carbs to see
if that improves throttle response. Stock 74 on carbs are really
amazing and are so smooth but maybe they are holding things back -
always need a new excuse. The custom DYNA Ignition has been replaced
with a fully programmable Ignitech so we'll see how that changes
things. It is small and light and easy to program. With a
little cheating, it was able to have a rev limiter, two step launch
rev control using the clutch switch, push button shifting with
programmable kill time off the horn button and programmable ignition
timing. Given that the
limiting factor is the rider those changes may not be enough to make
much of a difference, but it's always fun to explore new ideas. |
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