Hi
On my 89 flhtp my speedo every once in a while is bouncing up and down , if I'm traveling 100 kph it will bounce down to 85 and up to 105. I pulled the speedo cable and oiled it and everything seemed fine. Sometimes it works quite fine and sometimes not. Speedo has 145000 kilometers on it.Any ideas?
I'm also looking to buy another on flea bay but I'm not sure if I need to stick to 89 or if other flh years are the same with the gear ratio. I did check bikebandit and through there chat found out they can't get the exact speedo as my bike.

 

I had some weird issues with mine, and found it was the drive unit (at the axle) tab had broken off. The nub that was left would grab most of the time, but would occasionally slip out of the hole in the brake rotor and make a squeal. I went nuts looking for the cause; thought it was a wheel bearing or something.

 

I did replace the drive last year and actually checked the tabs a couple weeks ago when it did this same thing and I pulled the cable out by reaching through the headlight pod hole and loosening the cable.

 

When it happens, does the speed indication drop for a second, then bump up for a second and then return to 100 or does it randomly bump up without a drop first? If it drops and then increases, I'm thinking that there might be binding between the cable and the outer sheath even though you've lubed it. The inner cable might tend to wind up a bit and then release if it were binding at times. Have you disconnected the cable at the axle and checked to see how much torque it takes to spin the cable? You might want to check with the forks full left, straight and full right. It seems weird that the indication would go high at times.

 

It goes down for a second then up for a second and sometimes seems normal. I did lube the cable last time I had it out and it didn't do it again until now. Maybe it would be better to try another cable first before looking for a speedo.