GT750 Drag Bike

[tz375]

Kevin,
Congrats on the results so far. That's a heck of an improvement. Is there 0.5 to be picked up with starting technique?

That explains the worried looks on those H2 riders.
Good luck

[water cooled]

Hi Richard,

I dont think I can pick up much more than 2 tenth with a good launch but thats just a guess. The air quality is moving around during the day so jetting is a little tougher for everyone. With Qualifications over, we have to Dial In and just try to hit our number. Hopefully its cool, crisp air today too. Those new chambers look pretty sweet. I received more compliments on them than anything else....and they sure made this GT pick her head up. Its a different machine now.

Kevin

[tz375]

2010-11 upgrade program:

Slipper clutch
Light thin wall chrome moly copy of the stock frame (cheating is allowed right?)
Carbon tank cover over a small aluminum fuel cell

...

[water cooled]

Richard,

Definitely on the right track...need to lighten up everything possible. The rule for the "Modified" subclass says the bike must use stock engine cradle. I dont know if that means just the stock frame tubing from the rear motor mount to upper front motor mount of if it means the entire stock frame without the swing arm and struts. But I need to dump about 50-65 lbs off the bike which will not be easy. Im now within .5 sec of the Index for the modified subclass so it might be well worth staying in that class to see if I can capture that before moving on to "Altered" (and a much lower Index).

More importantly, we had a new racer this weekend. Joe Johnson came from Wisconsin to race his GT750 in the "Stock" subclass. He's already made the most important decision....to show up ready to race. Super Eliminator had the largest entry list this weekend and our group continues to grow. S/E is now managed and operated by the S/E racers so with 22 entries this weekend and all of the registration fees going back to the racers the payout for 1st was over $1k and runnerup over $500. There were also payouts for Semi Finalists. Because its based upon a bracket race (Dial In your own Time) everyone has a chance to win.

[tz375]

Kevin, Would it be worth your while top do a couple of test and tunes to get consistency with this new combo and get it dialed in before the next round of changes, or have you pretty much got it nailed? I can't imagine what it's like to race with so little practice time when it all comes down to the start.

50- 60 pounds is a big change, but that frame is really heavy. It would be quite easy to replace the back end with thin wall Cro-Mo and to take a pound or two out of the top tubes etc, but 50 is a lot of pounds.

Hollow Ti axles would help I suppose and T1 fasteners all around would make a difference. Aluminum fasteners on side covers all take off ounces which add up to pounds.

Wheel bearing spacers should be cross drilled Aluminum, if they aren't already. Aluminum billet triple camps with Ti bolts would drop some more. Hey, this beats the heck out of spending my money....

[water cooled]

I was thinking more like dumping the springs and oil out of the front forks, PMFR triple clamp, dumping the conventional 12V 4 amp battery, radiator, most of the water, molly swingarm that holds air for shifting, 520 chain conversion, stuff like that. The weight is in there, just need to chisel it out.

BTW, its not easy to launch without practice....its like threading a needle thats on the other side of the room and you have to throw the thread like a dart with one eye closed...yeah, thats about it! However, about 20 other guys are really, really good at this.

50# is probably optimistic but its a target.

[Barry S.]

Are you required to have 2 brakes? Loosing one would be a lot of easy weight to remove.

[water cooled]

Hey Barry S. yes....you have to have front and rear. I still have the stock front caliper which is not really the way to go but couldnt get the Grimeca to fit with that rotor and a spoked wheel. I agree the frame is very heavy. There is plenty I can do to get some weight out using the stock cradle. That will be this winters project I suspect. I do have a much lighter frame but it pushes me into a different subclass. Need to iron a few things out still before I switch over.

[tz375]

Kevin,

That front disk has to go. Get one from say a CBR600F2/3. They are much lighter and there must be lighter calipers. It will need to be a single sided to clear the spokes or a GP Brembo - they work - don't ask me how I know and the answer is No it's not for sale.

PMFR triple clamp? I just googled that. Oohh. That's nice (and light). Tasty.

Try a LiPo battery http://www.fullspectrumpower.com/products_pulse.html" onclick="window.open(this.href);return false;" onclick="window.open(this.href);return false;" onclick="window.open(this.href);return false;

And that kickstarter shaft is super heavy. Drill it more from the inside and then drill out the outer side - try not to break through though. Did I ever ship you that light water pump drive gear or is it still gathering dust around here? What is on the left end of that crank? Hint. "Not much" is the correct answer.The tacho drive is gone yes?

Did I mention that there's p[robably 5 pounds or more of surplus metal in the water jacket in teh barrels, and there's those vestigial fins just taking up space.

And you are right, that swingarm looks a little heavy.

Radiator - overrated. And why, may I ask does that frame still have pounds of heavy cast iron engine and radiator mounts? There's an easy couple of pounds right there.

520 chain - a must.

Those new pipes look awesome BTW.

[Suzukidave]

I dont know if the Kawasaki guys said but a coat of Mop n Glow floor wax on the bare pipes will help keep them from rusting up so you dont have to paint them

[water cooled]

Dave,

I use a product that I buy from Vertex Industries called "Colonel Brassy" Dont know if you have heard of it or not. I brought it to the track and even the most seasoned veteran pipe builder came by and were impressed with this stuff. http://vertexind.com/colonel-brassy.htm

I had been using WD40 after cleaning the pipes up with the Colonel but one of the other racers also told me about the Mop-N-Glo. I haven't tried it yet but I will. Nearly all of the racers in Super Eliminator (2-stroke) have bare metal pipes so we all have some technique to keep them looking sharp. The Mop-N-Glo was a new a one that I hadn't heard before.

My new pipes are going back to Michigan for some fine-tweaking and hopefully squeeze out a few more HP. I purchased a new clutch perch from Star Racing that has a switch mounted below the lever so I can use the MSD like a 2-step and hold RPMs steady at a specific level to launch while keeping a WOT. It should help with consistency when launching (I am terrible at this) but you can't stay on the 2-step very long as you'll load up the cylinders.

It looks like most racers hit WOT on the first or second light.

[water cooled]

This is worth checking out if you like 750 2-stroke drag bikes. Most of them are Kaws, but there is a Suzuki lurking in there too...

Super Eliminator has 2 official events that are being scheduled during 2011, both at US-131 in Martin, MI but its a testament to the strength of the 2-stroke racers that come from all around the great lakes and as far as Texas and NJ that they intend to survive (and continue to expand) well into the future!

Just thought you might like to check out some pretty sweet race bike pics....hope you enjoy.

http://www.dragbike.com/dbnews/anmviewer.asp?a=6101&z=3

[tz375]

What's the plan for this winter's rebuild Kevin?

The next stage in lightening perhaps?

An extra HP or two?

Nitrous?

Are the Ohio skunk works burning the midnight oil yet?

[water cooled]

Hi Richard,

I have a plan to shed about 11-12 lbs. off the bike...(cost effectively) which will put the race ready weight at just under 379 lbs. Joe Johnson is going to help me prototype the cooling system mod that will eliminate the radiator to run all cooling through the Bypass line only. The key, is to not starve the pump at any time which is tricky since there is not much surplus water available with the radiator gone. Water will basically circulate through the block and return through the Bypass line functioning much like a stock bike with the thermostat closed...(except, I wont have a thermostat). The coolant Inlet and Outlet will be blocked off and pressure relief will be directly above where the thermostat would normally be located. I'll add a small overflow for expansion that will return water back as the motor cools after a pass. Motion Pro has some very light weight bottles for this.

The pipes will also get some work but that will wait until after February. Maybe bump up a couple HP.

I replaced the clutch perch with a lever/switch combination that will allow the MSD hole-shot feature to work. That wont make the bike go any faster, just more consistent when launching. Just cant stay on the 2-step for more than a couple seconds. I'll give it a try and see if it is effective or if causes more problems than it solves.

Im also going to switch to ATF in the transmission and see how that works with the ALTO Red Eagle plates. I have a complete (stock) clutch pack if the ALTO plates are not performing but I expect they will. The ALTO clutch pack contains one additional friction plate and one steel.

I have some work to do on the front forks but its more maintenance than anything to replace the seals. I also have a 1974 gas tank that I may cut the bottom out of and clean up to use as a shell and install a smaller aluminum tank to contain the fuel better rather than allowing it to slosh around in there. I dont think my current fuel setup has caused problems yet but Im sure its not the best approach using that big tank.

Now that the jetting is on, I may get the Power Jets installed. If nothing else, it will help a great deal when jetting changes are needed in the pits.

I hear there may be three Suzuki GT750s racing next year. We'll see if it pans out but I think it is very possible to see by June 2011. Two will probably run in the "modified" class and one in "altered"

Looks like you are making good progress on the Phatt Traka. Maybe spring time? I sure hope that you video tape the startup and first ride and post it on the Board. I still need to get those pipes out to you. I have done a terrible job making that happen since the racing season was over in September. I owe you and Dave an apology....Sorry

[tz375]

No worries mate. It's too cold to run them this week but that time will come. I'd wait until after the holiday shipping crush. I would like to test them the first warm day we get in the new year

On the cooling system I'd throw out the water pump and gears and fit a small dirt bike radiator and electric pump. It will probably not turn on until the return run, so it won't draw much power. the bypass sends water in the wrong direction. That might work in terms of cooling the heads first and then the area around the exhausts, but that hose tiny and may prove problematic.

Look at an electric pump and work out the weight difference. I wouldn't go without a radiator because I think that there's insufficient volume of water in the block and head to remove heat.

Rather than ATF, check out an aircraft trans oil. We used one classified as ZERO viscosity in our race bikes for a couple of season and it worked fine. gears are highly stressed so my preference is a M/C specific oil like Silkolene or Motul. I haven't used ATF in a race trans so I can't say it won't work.

I guess if it works for teh H2 boys then it should work in a GT