Old motorcycle info needed

[motor-officer]

I am looking for the following info on some old motorcycles. I have tried the internet and some reference books but have gotten conflicting or no answers. If you can help or steer me towards a person(s) or other reference(s) it would be greatly appreciated. I need the following info as published/supplied by Harley-Davidson and Indian:

A. Stock horsepower.
B. Stock weight.
C. Top speed.

I need the info for the following motorcycles:

1. 1935 H-D 74 cubic inch side-valve (flathead) motorcycle.
2. 1935 H-D 80 cubic inch side-valve (flathead) motorcycle.
3. 1936 H-D 61 cubic inch overhead-valve (knucklehead) motorcycle.
4. 1936 H-D 74 cubic inch overhead valve (knucklehead) motorcycle.
5. 1935 Indian Chief 74 cubic inch side-valve (flathead) motorcycle.
6. 1947 Indian Chief 74 cubic inch side-valve (flathead) motorcycle.
7. 1953 Indian Chief 80 cubic inch side-valve (flathead) motorcycle.

[Rubone]

#4 on your list is easy:
A=0, B=0, C=0. 74 cubic inch knuckleheads do not exist until '41.
The info you are asking for is not something that was published back when those bikes were built. Neither H-D or Indian published such figures and the advertising of the day skirted such issues. Mine is better than yours was the ad campaign of the day and no one wanted to be overweight by ten pounds or down 5 horsepower. Such things as dyno tests did not exist, in fact even the factories did not use them! Horsepower was usually an educated guess at best! Some Export copies of sales literature list such things since many countries required as that info for import purposes. Military specifications also usually contain that info, at least pertaining to weight. No one dared touch the top speed issue and if you find it mentioned it will be biased heavily. You could take ten examples of each of those and be hard pressed to get a consistent number.
May I ask why are you looking for this info? It doesn't show up because it wasn't important then, or now!
Robbie

[exeric]

Great reply Robbie. It should also be noted that in the early days, horsepower numbers were based on a different standard that reflected a low number so taxes would be lower.

[pisten-bully]

In the Indian Riders Instruction Book (which you can download from this site) there is a horsepower number for all the models covered in the book, likely for registration purposes? But the number is listed as "Rated Horsepower N.A.C.C.".... so what is that? It's not a very big number!

[Rod]

A little book called 100 Harleys by Tod Rafferty says the '36 EL (knuck) has 40 horsepower, weighs 565 pounds and has a top speed of 95mph. Price is listed at $380. I can't find any mention of where Tod got his numbers.

[Blupacer]

Jerry Hatfields book Inside Harley-Davidson has some factory dino charts on a 1938 EL, a little over 42 HP,
See page 152
Steve

[Chris Haynes]

Jerry Hatfields book Inside Harley-Davidson has some factory dino charts on a 1938 EL, a little over 42 HP,
See page 152
Steve

Here is that dyno on December 14, 1938.

[Steve Slocombe]

Jerry Hatfield shows a lot of early 1930s dyno information in 'Inside Harley-Davidson'. The 36 bhp dyno curve for the new 'TNT' Big Twin flathead motor is also shown in the 1934 Harley sales brochure.

[pisten-bully]

In the Indian Riders Instruction Book (which you can download from this site) there is a horsepower number for all the models covered in the book, likely for registration purposes? But the number is listed as "Rated Horsepower N.A.C.C.".... so what is that? It's not a very big number!

Still wondering.... anybody know what N.A.C.C. refers to? For a Chief motor the Indian Riders Instruction Book lists 8.45 as the "rated horsepower".

Just curious!

[Rubone]

N.A.C.C. refers to the National Automotive Chamber of Commerce and was used for licensing purposes. It did not take into account the stroke of an engine and was merely based on a simple formula which was multiplied for more cylinders. It had no relevance to actual "Brake " horsepower.
The dyno Chris pictured was used for development purposes and is a water brake system. It was not used to check actual output of production machines as was done much later when random samples were put on a dyno and tested. One reason claimed H-P figures were not listed was the large variation between different machines performance. If you publish H-P and top speed figures you are opening yourself up for lots of criticism from customers. Things such as assembly tolerance variations, state of tune, elevation, humidity, etc, all affected a bikes performance level. All things the factories had no control over. They were very cautious with certain information!
Robbie