The 101 Association, Inc.
For the preservation and enjoyment of 1928 to 1931 Indian Scout Motocycles
"You can't wear out an Indian Scout"
 

Help with Standard Scout drive shaft pinion

  • 14 Feb 2023 6:15 AM
    Message # 13095997

    Dear enthusiasts,
    although I have been following this forum for several years, I'm only a new member of this association.
    I'm from Germany and I've been working with Indian motorcycles since the early 90's, but also with other antique motorcycles such as Norton, Triumph or BSA.
    I've been in contact with the 101 Association for a few months and maybe one of my tech tips will be included in the next newsletter.
    I have more of these, so please PM if you're interested.

    Now I have the following problem, which does not directly affect the 101 but its direct successor, the Standard Scout.

    The years of construction 31-33 are a big problem at Indian with the procurement of information and parts because only a few motorcycles were built.

    I have a 1932 Standard Scout motor with helical gears in the primary drive. However, the primary is slightly longer than the 101, so the front sprocket on the crankshaft must be larger.
    You can see on the photo that the 33 sprocket of the 101 is 5mm too small.
    The sprocket on the 101 is 62.8mm in diameter and the sprocket required should be around 73.5-74mm in diameter.
    Mathematically, with the circumference and the same pitch, I get 39 teeth.

    My question now is whether anyone has experience with this engine or old literature and whether my calculation with the 39 teeth is correct.
    A part number from old parts lists would also be helpful.

    But maybe someone has one of those sprockets lying around and would like to give it away? If yes, please write a PM.
    I also need a good shaft for the intermediate gear and the two thrust washers. This is then identical to the 101.

    Thanks in advance and drive safe
    Manny

    1 file
  • 15 Feb 2023 10:26 AM
    Reply # 13098714 on 13095997

    Manny,


    I do not have my parts books available at the moment, I'm traveling.  The gear you need was used starting in 1931 on the Chief and carried through 1933 I believe on the Std Scout and Chief.  They are not terribly common but can be found, unfortunately I don't have a tooth count for you. The idler shaft would be the same for 22-33 Chief and Scout, so not terribly hard to find.

    One beauty of all 74" Chiefs, and possibly the Standard Scout is that virtually all the internal engine shafts, rollers etc are the same as late model Chief, so easily found.

    Regarding the needed gear and idler shaft.  I believe Randy Walker makes the shaft. Kent Thompson in New Hampshire may have the gear and he carries most of Randy Walkers parts. I would contact him. Unfortunately, Kent does not have email, he is old school with phone and snail mail.  I just tried to call him but he is out.

    Here is his contact info:

    Kent Thompson

    PO Box 548

    Fitzwilliam NH 

    03447-0548 

    603-585-6933 phone


    Good Luck!

    Gene Harper

  • 16 Feb 2023 2:16 AM
    Reply # 13099781 on 13095997

    Hey Gene,

    that's useful information. Thanks a lot!

    I will try to reach Kent and maybe he has the right gear.

    If anyone has any other ideas, I'd be grateful for any tips.

    All the best

    Manny

  • 17 Feb 2023 10:20 AM
    Reply # 13101592 on 13095997

    Hi Manny, '32 parts list showing the drive pinion.



    3 files
    Last modified: 17 Feb 2023 4:17 PM | Harry Roberts
  • 19 Feb 2023 12:24 AM
    Reply # 13103192 on 13095997

    Here's pictures of the different versions of gears. Early Scout with 30-40-77 teeth count, 101 Scout and 22-31 Chief has the same gearing 33-36-84, but different shaft diameter, and later Chief and Std Scout with 39-36-84. I don't know the shaft diameter of the 39 cog gear. 

    33 cog Chief gears might have had a larger diam of the shaft taper in years pre -28, and same taper as the 101 in the same years, but I am not sure. 

    Courtesy of Ralf Spindler, shown is a Chief 33 cog gear on a Scout shaft.

    In order to fit the 39 cog gear without changing the 36 cog intermediate gear, the case is a one, two, three year special...before the chain transmission was implemented.

    I think the idea with the 39 cog is to speed up the gearbox gears in order to even up and lower the thrust impulses from the engine, and make the gears in the gearbox last longer...And also compensate for the large chain sprocket needed on the brake drum..

    7 files
    Last modified: 19 Feb 2023 1:06 AM | Carl-Erik Renquist
  • 10 May 2023 2:46 PM
    Reply # 13198479 on 13101592
    Harry Roberts wrote:

    Hi Manny, '32 parts list showing the drive pinion.



    Hi Harry, sorry for the late reply, but i had very important family stuff to sort out and couldn't take care of my motorcycles for the past few months.
    But now I've solved everything and have time again.
    Thanks for the pictures. That helped me alot.
    All the best
    Manny
  • 10 May 2023 3:05 PM
    Reply # 13198509 on 13103192
    Carl-Erik Renquist wrote:

    Here's pictures of the different versions of gears. Early Scout with 30-40-77 teeth count, 101 Scout and 22-31 Chief has the same gearing 33-36-84, but different shaft diameter, and later Chief and Std Scout with 39-36-84. I don't know the shaft diameter of the 39 cog gear. 

    33 cog Chief gears might have had a larger diam of the shaft taper in years pre -28, and same taper as the 101 in the same years, but I am not sure. 

    Courtesy of Ralf Spindler, shown is a Chief 33 cog gear on a Scout shaft.

    In order to fit the 39 cog gear without changing the 36 cog intermediate gear, the case is a one, two, three year special...before the chain transmission was implemented.

    I think the idea with the 39 cog is to speed up the gearbox gears in order to even up and lower the thrust impulses from the engine, and make the gears in the gearbox last longer...And also compensate for the large chain sprocket needed on the brake drum..

    Hi Carl-Erik,
    sorry for the late reply, but i had very important family stuff to sort out and couldn't take care of my motorcycles for the past few months.

    Thanks for all the info.
    The shaft of my crankshaft is the larger one which is used in later 101, Sport Scout and Chiefs.

    With the 39 teeth on the crankshaft the gear ratio in the primary is 2,15 which is quite the same as in after 33 models with the chain primary drive which is 2,16.
    I think it's like you said with the speed of the gears in the gearbox and the greater sprocket around the brake drum.
    And aditionally after '33 the road conditions getting better and average speeds gone up higher so the factory used a completely new overall gear ratio.

    Unfortunately I couldn't find a good original 39 teeth pinion gear but Mark from Crazy Horse Indian Australia has one of these in non usable condition as a sample and now he'll ask the guys in Australia who reproduce the scout gears he has in stock if they could do a small series of the 39 teeth version as well.

    When everything will run well I'll get a new one in the next weeks.
    I'm really looking forward to that.

    But thanks a lot to all of you guys who helped me out with pictures and the needed information!!!

    All the best
    Manny
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