Which speedo drive gear teeth for 1949EL

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thsmith
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Which speedo drive gear teeth for 1949EL

#1

Post by thsmith » Sun Apr 10, 2005 6:36 pm

I just bought a rebuilt 1948-52 speedo for my 49, the odometer is reading half the milage than I am actually traveling. The speedo drive gear I have has 13 teeth, is this correct ? If I change speedo drive gears do I have to do anything with the trans speedo drive gear ?

Thanks,

Tracy

P.S. the mph appears to read about half but at high speeds starts to jump around.



VT

#2

Post by VT » Mon Apr 11, 2005 12:06 am

Good question. The speedo you rebuilt is probably a 2:1 ratio for '36-67 Big Twin transmissions. (1:1 ratio speedo ratio's are for '68-73 servi-car) The drive unit assembly (VT 36-0810) for '36-61 Big Twins (67130-36) has 11 teeth. The drive unit assembly for '62-67 (67130-61) has 13 teeth. I think... that having the 13 tooth drive will make it read half the speed you're traveling. Mine does too.
Just wondering, does your speedo have a m.i.p drive cable stem or f.i.p. ? Male pipe is aftermarket. A female connection is OEM.
Last edited by VT on Mon Apr 11, 2005 3:48 pm, edited 1 time in total.

thsmith
Posts: 111
Joined: Mon Nov 15, 2004 7:59 pm
Location: Plano, TX
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#3

Post by thsmith » Mon Apr 11, 2005 1:52 pm

VT,

The cable is male. It looks like Palmers book once again is the best source of information. Not sure what the deal is with my tranny but the drive is like you said for a 60s and according to Palmer the drive gear in the tranny may not be right either. The only way I will know for sure is pull the tranny and pull the top and count the teeth. May have to change that gear as well.

Not sure what would happen if tranny gear was for a 60s and put the 11 tooth drive in it.

I guess that is my next project.

Thanks,

Tracy

VT

#4

Post by VT » Mon Apr 11, 2005 3:40 pm

yep, Palmers is an oasis of information. He refers to OEM speedo's and their cable hook-ups on page 442. He says that "'36 to 61 transmissions use a 11 tooth drive unit and a 7 tooth drive gear staked onto the countershaft cluster inside the transmission". And, that "All '36-61 speedo cables have male fittings on the (speedo-end) of the cable (OEM speedo's of those years would then have a female connection on the back of the speedo) and a female connection on the cable at the trans. end as usual". My guess is, that if you count your trans. countershaft cluster you will find a 7 tooth gear and that changing out your 13 tooth drive unit to an 11 tooth will make your speedo work right. But, I will call a higher authority and find out, and order an 11 tooth drive unit from him and post the results when my re-pop speedo Pan is back on the road.
A point of reference for re-pop speedo's (which are all male connections on the back) and replica builders, is that the ONLY cable that will work with a re-pop speedo is the female x female. That cable is not listed as "the one you need" in the V-Twin catalog. It's part number is (VT 36-0621) and you won't find it in the "Vintage" section. It's listed towards the front of the catalog in the "modern" section as a '62-80 FL black vinyl speedo-cable and it has a 5/8ths female connection on the speedo end of the cable, for the male re-pop speedo's. Do not order the 36-0620, it is for the OEM female speedo's.

thsmith
Posts: 111
Joined: Mon Nov 15, 2004 7:59 pm
Location: Plano, TX
Contact:

#5

Post by thsmith » Wed Apr 13, 2005 5:07 pm

I assume the countershaft speedo drive gear can be changed. Any done this ? I think my tranny is a 1963 with Jockey shift top but the speedo drive gear is probably wrong. For now I want to just change the drive and drive gear so my new speedo work properly. I will try to find the right tranny case later.

Thanks,

Tracy

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