Originally posted by: thebigshow
Big Dog = Someone who ACTUALLY races there OWN bike.......if randall piloted all of "chit talkers" bikes , would that make them "big dogs" too???? hmmmmm , somthing to think about...

Originally posted by: DSNUT
Where the weight is located certainly makes a difference. Internal rotational and reciprocating mass are the biggest help pound for pound. External rotational mass is next. Then unsprung weight like the dead weight of tires, swingarm, a-arms, axles, anything found on the bottom side of the suspension. lastly is sprung dead weight.

Unfortunately suggesting that my rational is flawed because I am not addressing exactly where the weight is located is like pulling into a culdesack..........it doesn't go anywhere.

Here are the two results of attempting a 3.7 with a stock bore DS650: Either you do a 3.7 or you don't. There is no other result that can come from the attempt.

How do we get there? Large adjustments like light weight rigid chassis, built race motor, NOS. Smaller adjustments like 520 conversion, lightened flywheel, gearing, number of paddles, . Even smaller adjustments like tire pressure, chain tension, healthy breakfast and a good nights sleep, etc.

If the large adjustment technology is not even close, all the smaller adjustments in the world will not get the job done.......i.e. worrying about if we are cutting deadweight or reciprocating mass[img]i/expressions/face-icon-small-wink.gif[/img]

First lets look at the Large adjustments......right now the most RWHP that has been broadcast to the sand drag world seen from a stock bore DS on NOS is about 103 hp.......that I know of anyway............that has a suitable drag racing curve that is 95+ for a duration of 2k rpm or more.

The lightest wet chassis that we have heard of for the DS650 is 265 lbs.............unless someone has something to share about a lighter one[img]i/expressions/face-icon-small-smile.gif[/img]

We have precident, which is the best way to predict future results, of a 105 hp bike that weighs 265 running on a slow track that was costing everyone i talked to about 2 tenths compared to a dirt/sand track running a 4.16. Correct for the 2 tenths and you have a possible 3.96 on a bike that is ounces from having the least unsprung weight, reciprocating weight, internal and external rotational mass and dead weight possible with current technology and investment. That is with 730cc torque so that will most likely cost the stock bore a few hundreths........which could conceivably put us at the 4.0 for a stockbore with current technology and investment.

We have a 280 lb bike with 116 hp with all the same weight technology, except dead weight which is 15 lbs higher and the same drag racing horsepower curve with about 10 more RWHP and a fair amount more RWTQ that ran a 3.96...........the torque was of arguable benefit because a smaller percentage of the overall torque and horsepower were getting to the ground.

Both of these examples are excellent precident to consider because they are of same engine configuration and within a few hp and torque numbers and are within a few lbs with similar technology and power curve and similar NOS shot as the stockbore setup in question..........unlike trying to draw a 4 cylinder heavyweight bike into the discussion that would only muddy the waters.

Now, lets look at the 3.7 number. Since no bike of similar technology or configuration has ever turned a 3.7, we have to look elsewhere for precident that will give us useful information. Sandbomber's Twisted Sister as i recall can duplicate 3.7 runs with a bonzai run of 3.6. Obviously it is a 2 stroke so it has a different rev speed, power delivery and torque curve than a single cylinder 4 stroke. That being said, it can still give us useful information as to the large adjustment requirements as listed above. Power, weight, etc. This gives us a little glimpse of what it will take but it doesn't account for some unknown variables until we pioneer that far with our DS motors. Glenn will have to chime in to tell us the power and weight of his Shee that runs 3.7's.

I will grant that a 100 hp 4 stroke vs a 100 hp 2 stroke of equal weight will prove the 4 stroke faster because of torque curve and delivery. Factor that in before you make a decision on what it will take to make a single cylinder 4 stroke run a 3.7.

Bottom line, I believe it will take more hp and less weight than current technology and investment can produce to run a 3.7 with a bigbore stroker. It is even less likely that a stockbore could do this feat. The good news is it will happen someday...........but it will be awhile and it might require development of billet crank cases to allow more than 900cc's and it might take carbonfiber frames, lol (Glenn)[img]i/expressions/face-icon-small-smile.gif[/img] and it might take someone with lots of money to learn how to tune 60 to 70 hp NOS gains for a stock bore to even dream of it..............someday.

Btw, anyone who reads all this needs to spend less time on the internet and more time with their family[img]i/expressions/face-icon-small-wink.gif[/img], lol

Ron

Originally posted by: rcoop
Good information but your facts are a little off . i think you need a disclaimer that this is the most power a stock bore you know of and the lightest ds configured bike you know of. 250 lb wet chromemoly Ds is already done. Make that Ti and your are down to 230. With the current stock bore technology down there on NOS this will put you in the 3.8 on a good run. Now we can sweat the small parts for the last tenth. I'm talking on gas no need for the 40 percent mixes to make power. Keep watching you will learn something.

Originally posted by: choosetolose04
DSNUT, I do see a small hole in your speculation.....mph will most likely be a little higher than I first anticipated. Probably in the 88mph range. We ran 81mph at 4.1 at Planetsand and the 60ft times were terrible due to traction issues.