Speedo sluggish on Hydra glide

[pete baildon]

G'day and hope you can shed some light on the small dilema I have with the speedo on the 56.It will only go up to 25 and no further no matter how fast I go.I have removed the speedo and cable,tested the speedo with my cordless drill attached and it went from 0 to 120 and everywhere inbetween smoothly when I changed the drill rpm's,so I'm guessing the unit is fine.Next I tested the speedo cable in its installed position and it was easy to turn so I'm thinking the problem is in the drive in the gearbox,of which I have no idea how to access,inspect or test.Any enlightenment appreciated or perhaps something overlooked?The box is stock unmodified 4 speed.Since joining the forum I have been doing some homework on oil recommendations and there seems to be many differing opinions so I would like some advice as to what other forum members think about correct or better oils for engine,primary and 4 speed in my 56 which is stock,unmodified(except s&s carb)Most oils available here in Australia or online.Your thoughts and advice on this contentious issue will be appreciated,PB

 

[NEWHD74FAN]

Common problem with speedometer cable drive is the cable is a square wire end, with tightly wound spring body, the length of the internal cable inside the coax connector sheath...and typically break at the ends, or the gear reduction/square drive loses a tooth. Only thing to do is mechanical disassembly of that gear drive mech in the tranny case, or that cable...for broken part inspection. Costs nothing to disassemble, just be careful and methodical, so you do not misplace parts. As for replacement, the key is the length of the inner cable (have to be really accurate so both ends engage drive ends and diameter to ensure freerunning well lubricated cable substitute.

 

[glider]

My bet is in the speedo head. If there is too much play internally it will not operate correctly and doesn't register right. Picture a gyro spinning and then take that same gyro and enlarge the pivot points so it doesn't spin smoothly but wobbles around. I tried to explain the as best I could

 

[Breeze3at]

Hi Pete; Unless I'm really thinking wrong, the speedometer drive on your '56 is off of the front wheel, not the transmission. There should be 2 cables going to the front wheel, a brake cable, and speedo cable. If so, undo the speedo
cable and see if it's broken. You said you could turn the cable in the sheath. If you did this at the speedo end (tank), the inner cable is probably broken, there's no clutch action in the speedo drive. If the cable is not broken, look at the end of it, it should be square, if it's rounded off, it will slip. If the cable is good, your problem is in the drive gear. It's a simple gear with tabs that fit into the wheel, probably still available for your year. Post back with your findings.

For oil in your bike, I'd go with a straight 50 or 60. I use Spectro 50 in my Shovehead.

 

[pete baildon]

Thanks for all the possibilities guys,this is where I'm up to...Speedo is driven from gearbox,so I removed the unit and cable and visually looked fine,reinstalled speedo and cable,connected cordless drill to gearbox end of cable and speedo worked smoothly and went above 25mph in fact it sit anywhere smoothly depending on the drill rpm. the inner drive cable with the square ends had some end play but the speedo still worked fine whether i had the inner cable pushed right in or out,the end play in the cable is about a quarter inch and had no effect on speedo performance,so I'm still thinking its in the gearbox...Before I go there I'm going to jack the bike and run it with the speedo end of the drive disconnected and I''ll do an inspection of whats happening there with the bike running.Sounds a bit primative but it may shed some light...Thanks for the gyro description Glider,I got your meaning.Found a dealer for Spectro Oils in Australia and have a box of 50 and 60 on the way.Supposed to use SAE60 in the gearbox,could I use the engine oil or should it be specifically gear oil? Thanks again for the advise,till next time....PB

 

[glider]

Stick with the gear oil in the trans and save the engine oil for the engine.

Thanks for the update.

 

[Breeze3at]

Hi Pete; Unless I'm really thinking wrong, the speedometer drive on your '56 is off of the front wheel, not the transmission.

Well, I wasn't thinking wrong, I just plain didn't know that speedo drives were in the transmission from the late '30's to early 60's. Now I do.

 

[Jonas]

Well, I wasn't thinking wrong, I just plain didn't know that speedo drives were in the transmission from the late '30's to early 60's. Now I do.

My 1981 FLH has the speedo gear in the transmission. (It is not used though).

I wonder how hard it would be to change the Hydra Glide Speedo to be driven from the front wheel. It could been done pretty cheap as long as the ratio was the same for the speedo head. Would just need a cable, drive spacer for front wheel. Both for less then 50 or 60 dollars on ebay. Otherwise you will have to remove and dissasemble the transmission. Hours of labor.