1975 FX1200 custom with 4 speed. Trying to determine what the trans is so I can get a speedo drive unit for it. Just has a plate over the drive unit hole now. According to Harley it had front wheel drive unit from factory. How can I determine if it's 23 tooth, 13 tooth, etc??? Thanks

 

if its a real FX trans then it wont have the adjoining gear on the counter shaft to install a cable to it - you will have to completely disassemble the trans to install it at that point you cold make fit the speedo you already have if you know the ratio 1 to 1 / 2 to 1 or 2260

 

Bummer. I guess I need a closer look behind the cover where the drive unit goes in. Would I be able to see the teeth on the gear in the trans through that hole? I could count them to come up with the proper tooth count. The trans is frankenstiened. Has a mismatched top on it. It's a police frame with super glide motor. Trans could be anything. Im not familiar with the differences in trannys used on shovels and pans.

 

yes in the hole you could see the gear - i think 4 or 5 different combos were available all through the years 9 tooth 10 tooth 11 tooth kind of thing on the driven gear the drive gear has a 4 or 5 tooth - dont take that to the bank i am guessing as they still confuse me from time to time - you need to pick a year from to this to that and then match the 2 gears and the speedo to that set up - the later trans with the cable every speedo made is available in that ratio - and the 2 gears retro to any year 1936 to end of driven cable

 

It will be hard to determine what speedometer drive gear you have through the hole in the case. You really need to see the side of the worm gear to determine if it is the 7 tooth drive for the 23 tooth drive unit.

The last year the FX models had a tranny drive was 72. After that you will probably not find the worm gear pressed onto the counter shaft gears. To make maters worse, late model FX models had a counter shaft gear that had a cog type gear to use as an oil splasher instead of the worm drive and I believe it was machined into the part so it was not replaceable.

There are code numbers on the front of the tranny case, kick start side across from the oil pump. It will be letters and numbers. They will give you an idea of what year case.
YEAR TRANNY#'S

1962 A

1963 A and B

1964 B, C, and D

1965 C and D

1966 D,E,F, and G

1967 D and E

1968 E

1969 E and F

1970 F and G

1971 G and H

1972 H,J, and K

1973 K and L

1974 L,M,and N

1975 N,P, and R

1976 R,T,U, and V

1977 V,W,X

1978 Y,Z

1979 Double Letters

1980 Double Letters

 

Take a look at the right side of your tranny case. if it is anything close to a HD tranny this is what is there. (pic from my 75 FXE)



and on the front of the case, something like this



By '84 the cast numbers were on the bottom of the case and stamped numbers were on the backside bottom right area.

And if your tranny is set up for the front wheel speedo drive unit, you will not have a worm gear. It will look like this...




If it is set up for the tranny drive unit the worm gear will look like this set up

 

What Filth says is right.
You really should get a service AND parts manual. I have both the FL and FX parts books plus a service man. for the FL. Some FX parts are not listed in the FL and vise versa. Parts manuals also give years and models used on.
The tranny pages of both P manuals will clue ya into what goes with what.