| Author | Message | ||
     Xldevil |
The engine sprocket of my tuber was drilled out. Reduces power loss in the drivetrain and the strain on the left crankshaft bearing.   Ralph | ||
| Panic |
In theory a reduction in rotational inertia adds power (less used to accelerate the crank = more available to the wheel), but you're below the threshold of error here. I'd be very surprised if that produced any detectable change - almost no weight removed, and very close to the shaft center. No change at all in "power loss in the drivetrain". Has no effect on "bearing strain", unless it wasn't balanced after drilling - then it ruins the bearing. | ||
| Xldevil |
I'll see.Worth a try anyway,IMO. Btw.Weight reduction is 500 Gram-more than almost nothing. Ralph | ||
| Buellistic |
For every "12 POUNDS" that you can remove, you get "ONE FREE" Rolling Horse Power that does not show up on a DYNO !!! In BUELLing LaFayette | ||
| Xldevil |
And after Xmas,either way, I definitely have to remove some pounds .  | ||
| Matty |
Panic, That's 1/2 a pound off the end of the crank. It does make a noticeable difference in acceleration. I use lightened sprockets on all my race bikes. The before and after effects are pleasantly noticeable. Another item of interest are the Aluminum clutch baskets. HUGE difference in rotating mass there. I'm not using them yet, since it's a bit out of my budget, but the Bartels team loves them and they're holding up very well.  | ||
| Xldevil |
Matty 500 Gramm = 1.102 pound http://www.exrx.net/Calculators/WeightConverter.html Ralph | ||
| Matty |
That's what happens when I do math in my head... Anyone need accounting help??? I work cheap!  | ||
| Panic |
And its weight removal is rotating 1.75" (guessing) from the shaft center. This means that 500 gm has about the same effect as 20 gm off the flywheel OD (7.875" OD) - less than 1 oz. Weight off the clutch is also not that effective, but for a different reason. While the mean center of mass is larger OD the speed is reduced by the primary ratio, so the effect (compared to weight on the flywheel at the same OD) is reduced by the proportion of the square of the ratio. Primary = 1.60-1 (35/56) gives about 39% efficiency. | ||
| Panic |
Re: "For every "12 POUNDS" that you can remove, you get "ONE FREE" Rolling Horse Power that does not show up on a DYNO !!! " I've seen these comments before, but no one knows where they come from, or how the proportion was established. If it refers to simple fixed chassis weight, the proportion is, of course, meaningless since a 200 lb. trial bike and 100 lb. rider benefit much more than a 450 lb. bike + 150 rider. If it refers to rotational inertia it has even less value, since the exact location of the weight compared to the center of rotation and speed relative to vehicle speed is critical. A hollow driveshaft has almost no value - turning slowly and very small OD. BTW: rotating weight removal will not show up on a rear wheel dyno or fixed speed engine dyno but does add power. If it's a "rate of acceleration" engine dyno (600 RPM/second etc.) it will show up, and the faster the rate the more difference. | ||
| Buellistic |
Jeffery(AKA Panic): Quote: I've seen these comments before, but no one knows where they come from. or how the porportion was established. They came from the RACING days of Joe Lenord(NATIONAL NUMBER 98 and later INDY DRIVER) and Dick O'Brian at that time head of the RACING DEPARTMENT at Harly-Davidson(THE MOTOR COMPANY)... In BUELLing LaFayette | ||
| Panic |
But is that chassis weight? Makes more sense since it applies to a known weight and power. Yes, I've seen similar applied to drag cars with no basis. | ||
| Blake |
I think the 12 LB is equivalent to one HP is wrt to the typical racing machine/racer of the day and is for a drag strip scenario or similar hard all-out acceleration through the gears scenario. It would be fairly simple to calculate theoretically how much more HP it would take to accelerate a 612LB bike/rider through the quarter mile in 10 seconds versus one that weighed 600 LB. I'm hoping Panic will take on that challenge. | ||
| Blake |
I wonder how much a titanium primary chain, is doable, could reduce inertial losses. | ||
| Matty |
Blake, There are a couple outfits that have belt drive primary setups for the XL and I've wondered the same thing. Every tiny bit adds up! | ||
| Steveshakeshaft |
I'll raise you a Titanium Crank and a set of Magnesium Cases  | ||
| Blake |
Ever wonder why, when the final drive sees so much more torque (when in 1st gear) than the primary drive, the primary chain is so much stouter looking than our final drive belt? Why not just run a standard 520 chain in the primary drive? Anyone know the answer to that? | ||
| Matty |
Oh, you mean a 749R? | ||
| Rocketman |
Blake, in answer to your question. How many times have you replaced your primary drive chain  Rocket | ||
| Blake |
How often do you suppose you'd need to replace the final drive chain on your Duc if it were enclosed and bathed in oil? | ||
| Buellistic |
Should "i" ask about SHAFT DRIVE ??? In BUELLing LaFayette | ||
| Blake |
Even better, why not a small lightweight belt like that on the final drive? Could it be that... shock loading is a problem?  | ||
| Buellistic |
The XB12X and the XB Long have that BELT ... On the XB and BLAST models, would the shock have better loading if up side down ??? In BUELLing LaFayette |
