Board index Flathead Power-Technical Questions, Answers, and Suggestions Indians Sport Scout Info needed

Sport Scout Info needed

Post Sat Dec 01, 2007 8:22 am

Posts: 16
Whilst I await my new pinion shafts for my bobber project, I was wondering if anyone could tell me the following standard Indian setup?
I am after the standard factory sizes of the following diamensions for the 45 Sport Scout.
-Valves, both inlet and exhaust, what size diameter where they?
-Inlet/exhaust port sizes into and out of the barrels, ie the internal diameter.
-Size of the inlet manifold nuts, ie what size thread do they screw to?
-And finally out of interest, the internal diameter of the throttle side of the Linkert 1-1/4 carb (downstream end).
I would like to know this info as it would give me something to hang my hat on so to speak as I continue to nut out what direction to go with my stroked 741 Bobber project.

Happy Riding,
IR :?:

Post Sun Dec 02, 2007 5:05 pm

Posts: 3160
Location: Central Illinois, USA

The valves were 1 3/4" and the internal bore of the carburetor is 1 3/8" (excluding the venturi of course.)

I haven't a SS cylinder handy to measure the inlet nipples (Nearly everything was 24 tpi.), but the I.D. of the cast manifolds can vary widely.


Post Mon Dec 03, 2007 4:38 pm

Posts: 16
Thanks a bunch Cotten,

This info is great as it gives me some idea just how much smaller everything was on the 741. I am not proposing to make this thing into an all out beast, but it does give me some sensible sizes to aim at where and if needs be.

I reakon I can easily push the 741 inlet manifold from its present 13/16th (approx) out to around 1.1 inches, but it will require a custom inlet manifold and a bit of thought for the way it is attached to the threaded nipple on the barrel. (Probably the easiest way will be to make up a threaded packer to take a larger manifold nut).

I have to nut out if I am going to retain the M741 Linkert or go for a bigger one. At the moment I am looking at keeping it and installing a 'Thirty Fifty/841 HDA', 13/16 venturi. One advantage with the limitations of the 741 barrels is that stroking them, smaller carbs are not all bad news as piston speeds are not increased and there is a longer time for the induction and exhaust strokes.
This is the reason why I am keen to find out the nominal internal size of the SS inlet manifold, so I can make a more informed decision in this area, so if anyone out there can measure an old barrel they may have lying around, it would be very much appreciated.
As I say, I am still at the stage where I have yet to take a deep breath before I decide in which direction I will move with all this stuff. I know that keeping it all 741 standard is the safe way to go, but thats not in my nature, especially as I used to have a little single seat race car...I just gotta fiddle!
Thanks again to all that have and continue to answer my many questions.

IR :lol:

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