GT750 Drag Bike

[water cooled]

Dave D.

I contacted MSD and they confirm that the total loss system requires approx. 1 amp per 1000 rpms. My max RPMs are no higher than 9300 through the traps and capped by the MSD rev limiter at 10,000 rpm. So at 1A per 1000 rpm, the requirement to run the MSD is 9.3A or 10A up against the limiter. Im not sure what your particular ignition setup demands.

The 4S 4000 mAH has a constant discharge of 25C and burst discharge of 35C for 15 seconds. So, 4.0A x 25 = 100A and 140A burst. That should be more than enough.

MSD says that if the battery falls short on its ability to discharge sufficient amps at higher RPM, the ignition system starts to lose functions including weaker spark or its ability to keep timing especially if a retard curve is programed in. I found several other suppliers of the batteries, some that offer 5000mAh with 40C rates. The whole idea here is to save weight without giving up anything through the ignition system.

The battery manufacturers say that the rate of discharge figure is the critical number for what we are doing.

[tz375]

Kevin/Dave D
I need to talk to you when I get back the US about classes and modifications etc and the way I'm eating, HH classification is close....

I'm thinking EE/S or FF/S after I check piston size in this motor, or GG/S with the RZ350.

First night in Paris and scooter rider crashes in front of us - cut off by a car - some things are the same the world over. He was OK.

[water cooled]

R,

FF/S is standard bore GT and 738cc. The Index for FF/S is 14.5 which should be easy to beat and claim a National Record.

EE/S is first OS 70.5mm pistons or 749.5cc and the Index is 13.60 sec. EE/S/HH is 13.90. HH is defined as 200 lbs rider with all gear on. Helmet, gloves boots and leathers. I think a tuned GT could beat the 13.90 as well but it would be close.

[water cooled]

Here are a couple of snip-its from this weekend at Thompsons Dragway. Smokin' Joe invited me to come up and run the GT750 at his home track and the weather was perfect. The air was cold and sun shining. After swapping out a bad battery and tweaking the tire pressure and wheelie bars for the right combination, the day produced a new PR for the Buffalo along with a new 60 ft best.

Here are a couple pics and a short video...

[tz375]

Congrats - great way to round out the season. It also sets a baseline to work on through 2012.

[Suzukidave]

Kevin .. your big smile says it all

[water cooled]

I was pretty happy...down to my last two passes of the year and I had not gone any faster yet this year compared to last. It was a small improvement but a PR non-the-less.

That ZX-12R sure came on strong. Smokin Joe knew I was on a good run.... as we both passed the finish line, Joe looks over at me and gives me the thumbs up.....at 140 MPH.

[water cooled]

Went back out to Thompson's Dragway today. By 11am, the snow from yesterday melted and they opened the track for business. Here are some time slips on the 3rd and 4th pass of the day: Smokin' Joe, one of the top racers in S/E, took the Suzuki GT for a couple trips down the track....here are the time slips (bike is # 4312)
We captured all four passes on video and we will post them tomorrow...I hope. Smokin Joe produced some great ETs, knocking on the 9 sec door with this Buffalo.

[Herman T]

Congratulations on the excellent times on your bike!! It sure was a good feeling to hear about them. I guess this means that next year there will be a new, leaner and meaner Hatchet riding the bike as I am sure you will be going on a crash diet to get yourself slimmed down. All kidding aside (I hope), I'm thinking that with you riding you should be able to get into the 10.30's as the bike sits now. It would be neat if you got that 9 running against me next year. How cool would it be if you got your 9 and I got into the 11's for the first time on the same run.

[water cooled]

Thanks Gary....I have it on my calendar to make a pass with you at the first 2012 S/E event. Dual GT750 passes.....wonder if that has ever happened...

Here is a video my son Bryan made this morning from the footage taken yesterday at Thompson's Dragway:

http://www.youtube.com/watch?v=SwrVbtnyweY

[water cooled]

...modification to eliminate the stock radiator....weight reduction of 11 lbs which includes the weight of the water.



Pressure protection moved to the top of the cylinder. Connection with -8AN to prevent water line from blowing off during testing. Routed from the top of the bypass to the inlet suction side of pump. Basically, a closed loop. An overflow bottle will be added to accept about 5 oz of expanded water which is manually returned assuming temperatures rise close to 200F. Concerns about the flow rate through the cylinder at high rpms and ability to remove heat. Using a Daytona digital temp to monitor water temps up near the top of the cylinder.

[Suzukidave]

Thats a nice clean setup and saves a bunch of weight too

[Suzukidave]

Kevin , what did you use to thread into the head as that has been a huge problem as to find a banjo bolt that will thread into the head .. its like a metric pipe thread ?

[water cooled]

Hi Dave,

I used a RedHorse aluminum elbow fitting with 3/8th NPT for the cylinder head and -8 AN fitting for the hose end. Although the cylinder thread is metric, Joe measured that for me to confirm that its very close to 3/8th NPT....I researched the heck out of the threads....metric, british, straight, taper....you name it. The solution was to either drill out the threads and go larger or use the 3/8 NPT.

[Suzukidave]

Thanx for that tip Kevin .. something i didnt even think about .