The Quickest GT750 of All Time

[water cooled]

For the past several years, I have been trying to track down the "Quickest" Suzuki GT750 dragbike of all time. As a result, I have corresponded with some great 2-stroke riders and tuners.

Last year, Vic Force responded to a post I put up on Dragbike.com and Bill Baxter helped me get in touch with him. A few months ago, Vic put me in touch with Rob Miller and Dick Fortino who built what I believe to be the quickest normally aspirated GT750 dragbike in history. It has been great to exchange information back and forth with these men and my pleasure to get a glimpse into their accomplishments.

Their GT750 evolved over the few years that they developed it. I tried to post pictures in the order of development. The last few pictures show the single piece billet squish head that was machined by Vic. Dick did the porting and pipes throughout the development. Rob Miller was behind the use of Lectron carbs, tuning them and piloting the bike.

This team went on to win the 1977 National Championship in Competition Eliminator setting the National ET Record somewhere in the 9.40's at just under 140 MPH.

All Time Best Performance:
Best ET: 9.38 sec
Best MPH: 143

Their accomplishments are still incredible!

[H2RICK]

Thanks for the "ride" down memory lane, water cooled. Those guys certainly did some fine work on a very much underrated drag bike engine.
BTW, it's interesting to see that one of their sponsors was Sifton, who was a big aftermarket camshaft supplier to many of the top HD drag bike teams. It's ironic to see that decal on a stroker.

[tz375]

Amazing stuff Kevin. All so period - Lectrons, that small fairing etc, but the pipes are so short and fat - not at all period and that billet head a decade or three before they were copied?

Any idea how much HP it takes to do those times/trap speed and when will you pass those numbers and enter the records as fastest and quickest GT? No pressure now.

[Suzukidave]

It looks like they did what we had been talking about with the cooling system .. they just ran the water straight from the head outlet down to the intake without any radiator .

[water cooled]

Richard, I dont know if I will ever get near those times...thats pretty quick! I would estimate a total rider/bike weight of 480 including leathers and helmet would need about 130 RWHP to hit those numbers.

Dave, I had a discussion with them about the radiator. He said it was one of the first things to go. Removed the pump too. Just let it circulate naturally. Im going to attempt something similar but will keep the pump. I want to circulate through the Bypass hose. Its shorter and smaller diameter. I may need to slow the pump down as the rpms will be high and Im not sure if the passage in the lower case back to the sump can handle that flow rate.

[Suzukidave]

Maybe its time to look back at the electric water pump idea , you could gut out all the gearing to the stock pump and it would save ya at least a couple of HP not running the stock pump .

[tz375]

That explains the flat plate side cover on the left side - no gears in there. IIRC Bill Calcutt ran his without water. It only has to run for say 10 seconds on the line plus nominally 10 seconds of a run. Should be OK with no pump and just thermal circulation. I would try it sans radiator but using the main hose the way they did but leave the pump in.

If the temps stay reasonable, drop the water pump, quill shaft and gear train. That crank gear is a pretty heavy set up. There's 2 pounds right there. But you would need a plug to blank off the pump passages - or leave the pump in and remove the drive train and impeller.

Do we know anything about the two different right crank end covers? Is one a starter nut and the other a simple cover ? is there something else going on there?

[jaybob]

Look at those spindly front forks. Must be from a 185 LOL!!

[greasemonkey]

Maybe its time to look back at the electric water pump idea , you could gut out all the gearing to the stock pump and it would save ya at least a couple of HP not running the stock pump .

we use electric waterpumps from mobil-homes for years on the scooters we run. together with an inline cooler like this

but we only run 6~7 sec each run.

[water cooled]

Where does that in-line cooler come from. I looked at a similar one but it wasn't that nice. I only see a temperature rise of 28F on any given pass with the stock set up (that includes a burnout).

You're either running 1/8 mile....or you are very, very quick!

[greasemonkey]

it's 150 meters, we normaly run scooter with about 25hp (70cc) weight is about 100kg (driver inc.)
the cooler is made by HEBO that's a manufacturer from spain made for scooters its 20cm long hose dia. is 17mm.
7sec 2-stroke on a 1/8 would be a dream I fear