From the day I bought 531, the speedo has never worked. Having got the air issue sorted, and a new half exhaust fitted, now was the time to cure the speedo as well. Checked the head, that was fine, so took the drive out of the gearbox- problem obvious. Where there should have been teeth, there was a toothless grin. Worn out teeth, with two teeth missing completely.

Thought getting a new one would be a doddle, seemingly not. Tried J&S components- no. Tried Imperial- no. Tried Lional Moss- sold the last one a fortnight ago. J&S said try Ensign, they had some made. So tried Ensign, but theirs were for the fitting of tachos and have a different end fitting.

So! Has anyone got an origional speedo shaft they will sell me? They are about 8 inches long, with a slot cut into the top. At the bottom is a gear which engages in the gearbox. (The RML refurbs apparantly have a different system with a sender on the rear propshaft).

My bus number (if any): RM531

I may be completely wrong here, but I think that there are three different types depending on what ratio diff is fitted.
STD ratio needs a 14t Gear
Mid ratio needs a 12t Gear
High ratio needs a 10t Gear

Rob

Well, there you go. Didn't know that! Mine has the rotting stumps of 14 teeth.

My bus number (if any): RM531

Rob, I think the 4:08-1 ratio needs a drive with 11 teeth. Andrew Morgan is investigating having some made. Paul.

Also the tyre size fitted will have a bearing on it as well (In the service manual there is a full page chart relating to speedo cog teeth and tyre size and diff ratio part D22, section 9)

Part I have found so far has 13 teeth on the drive shaft (which with 900x 20 tyres is for 5.17 : 1 diff (monocontrol) or 1000x 20 tyres is for 5.17 to 5.22 : 1 diff (monocontrol), part number D1/25944 7 inch long.

Mark

Interestingly the axle ratios start at 4.14:1 and go to 6.80:1 and the drive shaft options have 11 to 18 teeth in increments of 1

My bus number (if any): RM1414 (sort of)