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Its generally accepted that there's a 15% HP loss due to the driveline on an automobile. i,e. If you divide the dyno result by .85, that gives a good approximation of HP at the crank.

Does anyone know what % is used for cycle dynos? There probably is a slight difference between chain, belt and shaft drives.
 

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Official BTK Forum Pot Stirrer
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don't know what the bike conversion is...sorry
 

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Sorry, I can't help either......But I just have to say.......Man, you've got one heckuva toy box there Petegtsv10!!! By the way, does that supportive spouse of yours have any sisters? :mrgreen:
 

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petegtsv10 said:
Its generally accepted that there's a 15% HP loss due to the driveline on an automobile. i,e. If you divide the dyno result by .85, that gives a good approximation of HP at the crank.

Does anyone know what % is used for cycle dynos? There probably is a slight difference between chain, belt and shaft drives.
Based on what I've seen claimed as crank HP versus what I've seen published as dyno results on a few bikes it seems like the delta is about 10%, 6-7HP on most of our bikes. If you think a 3500lb 250HP car loses 37HP through the drivetrain and a 650lb 65HP loses 6-7 it seems about right but far from gospel or scientific.
 

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RIP Deron Harden :-(
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seems to me like flynsouth is pretty close. from numbers that i have seen, 10% would work. i imagine it might fluctuate a little depending on the final drive of the bike. a shaft drive would most likely eat more power than a chain or belt.
 

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BRlawman:
No sisters, but 2 reasonably good-looking brothers!
 

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These data apply to 1600 Mean Streak which was gathered from the information already discussed in this forum:

Published info from Kawasaki Service Manual: (Assumed to be at the crankshaft):
HP = 72
Torque = 92.2

Dyno results of stock bike:
HP = 62.38
Torque = 79.15

Calculation : 13.4 % Loss in Hp from the crankshaft to real wheel
14.2 % Loss in torque

After a new intake, pipe and TFI:
HP = 72.93
Torque = 93.12

Bottom line: New intake system, exhaust pipe and FI controller brings the published stock crankshaft data to the real wheel.
 
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