There have been may threads dealing with modifications that are meant to increase HP or lighten the ST. Most of the time it is by people who are after more get-up-and-go. Others don't seem to understand how it works or why. I decided to throw this small example together to help them understand.
The top row shows 125 HP, 700 Lbs (figuring full tank of gas), 0.179 HP per Lb of weight (HP/Weight), and a percentage difference. I simply dropped the weight in 10 Lb increments and showed what the HP to weight ratio would be and the percentage difference from the top line (base line) figures.
Once I had the percentage figures I then calculated what the corresponding HP of a 700 Lb. bike would have to be to equal that percentage change. To see this look at the bottom line. If you could drop the weight of the bike 100 Lbs you would see a 16.67% HP to weight ratio change. To see the same performance change for the same 700 Lb bike would mean you would have to produce 145.83 HP.
So when someone changes their mufflers to brand X and reduces the bikes weight by about 15 Lbs. it is equivalent to a 2%+ HP gain. This is not counting any HP change that may be a result of the change.
The inverse is also true if you add weight to the bike. The difference is seen in a lowering of the HP to weight ratio instead of an increase. This would translate into less performance.
I hope I have explained this clear enough so that you might see why some of us do what we do to our bikes.
The top row shows 125 HP, 700 Lbs (figuring full tank of gas), 0.179 HP per Lb of weight (HP/Weight), and a percentage difference. I simply dropped the weight in 10 Lb increments and showed what the HP to weight ratio would be and the percentage difference from the top line (base line) figures.
Once I had the percentage figures I then calculated what the corresponding HP of a 700 Lb. bike would have to be to equal that percentage change. To see this look at the bottom line. If you could drop the weight of the bike 100 Lbs you would see a 16.67% HP to weight ratio change. To see the same performance change for the same 700 Lb bike would mean you would have to produce 145.83 HP.
So when someone changes their mufflers to brand X and reduces the bikes weight by about 15 Lbs. it is equivalent to a 2%+ HP gain. This is not counting any HP change that may be a result of the change.
The inverse is also true if you add weight to the bike. The difference is seen in a lowering of the HP to weight ratio instead of an increase. This would translate into less performance.
I hope I have explained this clear enough so that you might see why some of us do what we do to our bikes.
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lol.
