850 MK3 speedo drive/gearbox

Hi,

I've done a good search on speedo drives on this forum but still have some questions.

I purchased a speedo drive from Andover Norton, not sure what brand these are?, it only lasted 96 miles. The cylindrical gear has a lot of back & forth movement, approx. 6-8mm. My original Smiths has about 1mm movement but the gears are shot!

Also the drive hole for the cable is rounded on the inside, I purchased a new speedo cable from AN at the same time as the speedo drive so both were new. When I place the square shank from the cable in the drive it just spins around in place & does not move the gears.

I presume I'm suffering from re-pop poor quality?

It seems a bit hit & miss, some still have their original drives for 30+ years with no problems and fair play to them.

Some purchase re-pop and have no issues and people like myself, seem?, to be unlucky & get a poor quality re-pop?

Does anybody know of a 'good' reproduction speedo drive which will last at least longer than 96miles! The part number for the MK3 is: 06.5540
Is Emgo the only game in town when it comes to re-pop drives or are there other brands/better quality?

As always thanks in advance for any help/advice.

click said:

Hi,

I've done a good search on speedo drives on this forum but still have some questions.

I purchased a speedo drive from Andover Norton, not sure what brand these are?, it only lasted 96 miles. The cylindrical gear has a lot of back & forth movement, approx. 6-8mm. My original Smiths has about 1mm movement but the gears are shot!

Also the drive hole for the cable is rounded on the inside, I purchased a new speedo cable from AN at the same time as the speedo drive so both were new. When I place the square shank from the cable in the drive it just spins around in place & does not move the gears.

I presume I'm suffering from re-pop poor quality?

It seems a bit hit & miss, some still have their original drives for 30+ years with no problems and fair play to them.

Some purchase re-pop and have no issues and people like myself, seem?, to be unlucky & get a poor quality re-pop?

Does anybody know of a 'good' reproduction speedo drive which will last at least longer than 96miles! The part number for the MK3 is: 06.5540
Is Emgo the only game in town when it comes to re-pop drives or are there other brands/better quality?

As always thanks in advance for any help/advice.

Click to expand...

Click,
Search member PeterJoe for what he does with the speedo drive. I had one done for me and could not be happier. I think it is good for life! I will also see if I have any pictures.
Mike

The new speedo cables available have a 3mm square, whereas the originals had a 1/8" square. Marry that to the speedo drive that has the internal 'square' formed by four 'flats' squashed into the driven spindle, these aren't long enough so eventually the 'flats' round off the 'square' cable and you are left with a speedo drive that has very haphazard operation and a speedo needle flicking all over the dial. I repaired the drive on my Mk3 by making a new internal square for the driven spindle and a new bush at the cable fixing end. Also the little grease nipple is useless, it has a spring loaded ball that effectively blocks it. I remove the nipple and then pump grease in, then refit the nipple.

YING: Thanks for the replies. I'll check out the info. from PeterJoe, sounds interesting.

dobba99: The fact I got the new drive + the cable from AN you would hope both would match! (I know this is a presumption rather than a fact)
The bottom line from my point of view is I have less than 100miles on this new drive & it's now not working and it looks like there is massive wear on the movement of the geared spindle and the hole for the cable has rounded off internally so the cable can't drive it!
You could be right about the internal cable size, I'll see if I can measure this later. I have no way of measuring the internal part of the driven geared spindle in the drive + it has been rounded off!

As always with a lot of classic 'stuff' something simple turns into a more complicated series of factors which all must be considered before a solution is found!

Minor update.

I got another speedo drive/gearbox from Feked, it's made by LF Harris in the UK. Good service from Feked, order processed and sent over to me really quickly. Hopefully this last's a bit longer than the one I got from AN!!
I've sent the worn speedo drive/gearbox back to AN to see what they say about the wear on the cylindrical gear , more anon.

click said:

Hi,

I've done a good search on speedo drives on this forum but still have some questions.

I purchased a speedo drive from Andover Norton, not sure what brand these are?, it only lasted 96 miles. The cylindrical gear has a lot of back & forth movement, approx. 6-8mm. My original Smiths has about 1mm movement but the gears are shot!

Also the drive hole for the cable is rounded on the inside, I purchased a new speedo cable from AN at the same time as the speedo drive so both were new. When I place the square shank from the cable in the drive it just spins around in place & does not move the gears.

I presume I'm suffering from re-pop poor quality?

It seems a bit hit & miss, some still have their original drives for 30+ years with no problems and fair play to them.

Some purchase re-pop and have no issues and people like myself, seem?, to be unlucky & get a poor quality re-pop?

Does anybody know of a 'good' reproduction speedo drive which will last at least longer than 96miles! The part number for the MK3 is: 06.5540
Is Emgo the only game in town when it comes to re-pop drives or are there other brands/better quality?

As always thanks in advance for any help/advice.

Click to expand...

I don't know where AN gets them.

Several years ago there was a batch of them made that the manufacturer forgot the step of squaring the drive part. I got several different ones (Triumph/BSA/Norton Pre-MK3) from Wassell in a single order and they sat on the shelf for a long time. I was installing one last year on a Trident when I found the problem. All the ones for Triumph had the problem, none of the BSA, and one of the Norton. They are from EMGO but I doubt that EMGO makes them.

The originals were not hard to get apart - the current ones are very hard so I've not fixed them.

You can bet that sellers still have bad ones and don't even know. So, if you buy a new one from anyone, check that the drive is square! They should be completely square, not "kinda" square!

Also in that batch, all the ones for Norton had flash around the window where the gears meet. If that breaks off and gets in the gears they will jam. I ended up throwing the one where I found that away as I could not get it to run smoothly after a lot of trying. Today, I inspect them all and if there is flash carefully remove it without losing the bits.

If it weren't for those problems, the quality seems equal to the originals and the metal doesn't deform as easily on a Norton as the originals.