hp@rpm for 74 Chief

[Pandit]

Hello
To drive my Chief in Switzerland, I need "offical" informations about the power@rpm. Are there some written informations out there? I foud only in the Riders' instruction book the motor regristration data: Rated Horsepower N.A.C.C. (what's that?): 8.45. How much are these 8.45?
It's for a 1941 Chief.

best regards
Roland

[sirhrmechanic]

Roland:

8.45 is probably the 'taxation' horsepower, not the actual output. This would have been based on a formula from number of cylinders, bore stroke, configuration, etc. This is why continental and British cars are often referred to in "horsepower" terms such as 50 HP Napier or 40/50 Rolls-Royce.

There may be someone here who can provide a dyno sheet from a Chief. Or you might contact Kiwi Indian... they are reproducing machines and motors, etc. It is very likely that they will have some kind of a dyno chart or some kind of modern horsepower rating information that will help you. Not sure if their numbers will be considered 'official' but maybe you can weasel-word it as 'published' or something like that. I'd argue that even Indian's "official" figures back in the day were washed through the marketing department anyway... ;-) Official was probably whatever would help sell bikes.

Let us know when you find out! It's a neat question.

Cheers,

Sirhr

[fillibuster]

Roland:

8.45 is probably the 'taxation' horsepower, not the actual output. This would have been based on a formula from number of cylinders, bore stroke, configuration, etc. This is why continental and British cars are often referred to in "horsepower" terms such as 50 HP Napier or 40/50 Rolls-Royce.

There may be someone here who can provide a dyno sheet from a Chief. Or you might contact Kiwi Indian... they are reproducing machines and motors, etc. It is very likely that they will have some kind of a dyno chart or some kind of modern horsepower rating information that will help you. Not sure if their numbers will be considered 'official' but maybe you can weasel-word it as 'published' or something like that. I'd argue that even Indian's "official" figures back in the day were washed through the marketing department anyway... ;-) Official was probably whatever would help sell bikes.

Let us know when you find out! It's a neat question.

Cheers,

Sirhr

The first Indians models were identified by a horsepower characteristic, derived from the cubic inches (I think I read that), and that this went according to a standard-ish formula. Of course I've been curious about the formula. Sounds like the Swiss are interested in more modern characteristics.

I prefer the Prony brake test for horsepower.

[pisten-bully]

Roland, I saw this discussed on a different forum, some good information there but nothing "official".

http://http://www.caimag.com/forum/showthread.php?18912-Chief-1938-39-weight-and-HP

[cdf6333]

Back in the 70's at the Indian Rally in Westfield Mass, Chuck Myles brought a dyno and we "tested" all our bikes. I remember measuring 40 HP and a buddy on a stroked Sportster had the same 40, which surprised me. I had a pretty modified 80 at the time, Shunk cams, 1 3/4" SU carb, etc. Fun times. dyno162.jpg
You can't see the friggin chains holding the bike back or the fans blowing, but it was a loud event!