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Indian parts interchange ?

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Post Mon Dec 10, 2001 12:01 pm

Posts: 950
Location: Paris ::: France

I'm a complete Indian idiot and need help. I have a complete 741 barn fresh bike leaning against a wall of my garage. I never touched it because I've always been on other bikes and stuff. I may have found a complete 45" indian motor [I think the serial number starts with GVA] and think this might be the opportunity to build a real cool racer. Maybe you guys could help me out on few basic questions. Thanks!

- what's the difference between a scout, sport scout etc...?
- can the 45" motor fit into the 741 bike [without changing tranny etc...]?
- Does it use the same primary?
- Is the generator the same?
- how much is a 45" Indian motor worth?!? This is one looks like it's in really good shape. It's only missing heads.


Post Tue Dec 11, 2001 1:31 am

It's not a 45, but a GDA, which is Indian-speak for "741", = 1941 500cc (30.50") military junior scout. Full-size Scout 750cc motors are "F" code (1942 = FDB, etc.). The "good" Scout barrels won't clear the 741 frame (or any pre-1940 Scout frame). The late frame has a dog-leg in the back tube for barrel clearance, looks like the offset for electric start in 1967-* Sportster frames. 741 can make a nice racer, though - see Virtual Indian for NZ stuff.

Click here to see my Pages-O-Tech-Stuff

[This message has been edited by panic (edited 11 December 2001).]

Post Tue Dec 11, 2001 3:22 pm

Posts: 950
Location: Paris ::: France

Ok well something is not right then. The cases do say GDA [exact number is GDA25271], but the engine is close to a 735cc, definetly not a 500cc.

I noticed the intake manifold is "Y" shapped [with 35mm / 1.38" opening] unlike the one on my 741 which is "T" shapped [and smaller for 1" linkert].

Here are some more of the measurements found on the bike [rough figures]
Bore = 2.87" [73mm]
Stroke = 3.50" [89mm]
Valves [in & exh same size] = 1.75" [44mm]

Any ideas?

Post Wed Dec 12, 2001 1:27 am

Posts: 108
Location: San Diego
Eric: someone has put a 45 top end and flywheels in a 741 case. I think some old-timers ground the cylinders and heads to fit into the 741 frame.


Post Wed Dec 12, 2001 10:32 am

Posts: 950
Location: Paris ::: France

Cool, that motor seems even more interesting then! Is that standard size for valves? They look pretty big for stock valves!

Post Thu Dec 13, 2001 1:18 am

Posts: 950
Location: Paris ::: France

Is that a common upgrade? Do the cams need to be changed as well? If so, how much lift do the stock 741 cams have and how much do the 45" cams have? This will allow me to see if cams have been changed without dissassembling the engine. Thanks,

Post Thu Dec 13, 2001 2:30 am
I sent a guy some junk rods this spring and he is doing the 741 - 45" flywheel thing I'll email him on his progress and let you know Thanks FatDog

Post Thu Dec 13, 2001 7:51 am

Posts: 1002
Location: Ojo Caliente,NM,USA
The 741 used the same lower performance cam as all Sport Scouts that weren't Bonneyville. Check threw the back issues of the Virtual Indian there is a good artical on identifying cams.

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