GT750 Frame Weight Reduction

[water cooled]

Hi Richard,

I know that Larry Smith runs the Nitrous bike - Redline Motorsport. I think it is the fastest 2-stroke in the high 7's.

I think nearly everyone else uses some form of race gas like C-12, C-14, U4.2 or Q16. That probably covers about 90% of the racers I have seen so far. I haven't heard of anyone running methanol.

http://www.vpracingfuels.com/motorcycle ... num=208617

My guess is that most of the racers have about 120 RWHp give or take. Many of them have a bike weight of around 300-320 lbs and weigh 160-180. Leathers and helmet 10-15 lbs for a typical package weight of 470 - 515 lbs. This group of racers probably represents the bulk of the field.

If we set Bianco and Bird aside because they are in another league, the rest will usually run 9.1 - 9.9's which means an estimated RWHp of about 110 will get them to that ET at around 130 to 140 MPH

http://www.amadragbike.com/Horsepower.a ... 7124106586

The bigger guys of course weighing 200+ lbs can still run 9.5's with 120 RWHp...so except for about 4 racers, the bulk of the group are probably 120 RWHp or so...

http://www.supereliminator.com/

[tz375]

That's a lot of weight to shed from a GT. Unfortunately a set of empty GT motor cases weighs about the same as a complete H2. Everything is heavy - even the crankcases and they are not particularly stiff either.

The crank is heavy, barrels are incredibly heavy and so it goes.

Maybe if we leave the water out and fill the cooling system with helium....

If we replicate the frame in chrome moly, that would save about 20 plus pounds right there. It would probably be cheating but its only cheating if you are caught, right? Just kidding.

So nitrous and a blower it is then

[water cooled]

As it stands, my bike is 369 wet. With the front end swap nearly done and the cooling system change well underway, I estimate the GT will come in around 352 with just those two mods. The next two major items are the swing arm and tank and we might squeeze 7 lbs there. Then, cylinder head bolts and alloy bolts for the covers and an alloy handlebar (shortened) for an additional 1-2 lbs. I bet I could get the bike down to 345. That wouldn't be bad for the 2010 season. 112 RWHp with everything perfect might get very close to the 10 sec Index.

Maybe an additional 2 lbs. out of the frame bracing, radiator lugs, a switch to alloy foot pages (or no pegs)...a 520 chain conversion, lighter wheelie bars...

I agree, 112 RW will be hard... roughly 129 BHP...

BTW...I looked at the ET's going back in time. It seems that the slower bikes are usually winning the ET bracket race. The H2's might be lighter but the GT is pretty bullet proof. Im not trying to go faster than them, just get closer to my subclass Index of 10 sec./ consistently.

[Tom Garcia]

What would the HP offset be for a pint of Fleet Enema?

(Hey....I'm in the 200+ lb category...I would need all the help I can get!)

[water cooled]

It depends on when the enema worked...if it was before you left the pits a small offset applies...but if its during your run, no offset applies.

[two-stroke-brit]

have you tried either drilling through the front and rear axles and the swingarm bolt or replace with titainium also hollowed thro.
every little helps eh.
mark