Dominator 88 speedo drive set up

.. that some drives have a simple cylindrical spacer and as you say a boss fitting the spindle. As long as there is a spacer to stop the side of the gearbox caving in, and trapping the gearbox so it doesn't spin it should be OK. TBH just holding the gearbox in place by friction isn't brilliant design, and if it does spin the results can be catastrophic (winding the speedo cable round the gearbox and pulling the bars onto full lock).

I have recently rebuilt a couple of Dommy speedo drives.Its important that the top hat spacer is a close fit to the axle and that the drive main  alloy body  is not belled from being accidentally crushed  as it will foul the alloy hub cover and get dragged round as Ian says.. The1/16"CSK alloy rivets that hold the assembly are harder than the drive body so carefull to not wander off if you intend to drill and dissasemble.I had to use a big vice ,sockets and spacers to crush the bodies back into shape,alloy does not take kindly to this treatment ! so its at your own risk. The gears must not have wear flats or they can jam up.  The gearing must be the correct Ratio for the speedo. The swinging arm fork end must be at a true  90 degrees to the axle  when snug to the drive or bending forces can distort the drive body. Pattern drives are a gamble, Won't fit or last ??. You may like me buy a selection of rough drives and build a good one from selected bits ,or better to pay out for a good one.

Just looked on E-bay Loads of pattern Indian made stuff and New  Emgo copies ,for big money, shame they left out 3 of the 4 rivets !,  Would not last a mile  till the gears jam up. Emgo brake shoes help your bike go faster downhill I found.

Then avoid ebay and go to A Gagg in Nottingham. 

You will pay more, but you can at least talk to them about what you need and buy with confidence. 

One of the 'good' shops.

http://www.gaggs.co.uk

George. 

Hi Nigel, Gaggs,yes, The prices look good to me.    When you tighten the axle nut the drive will be very tightly clamped (it needs to be)   but its important that the  axle spacer /top hat detail all seat properly or the drive will get crushed and distorted ,easily done after you have been struggling with a puncture on a dark wet night.

I would just like to add that if you have the cover plate the grommets are a must and if not the sprocket sleeve nuts should be lock wired because if one comes loose and wraps the speedo cable around the spindle whilst you are riding then you will almost certainly wish that it hadn't. 

Unless things have changed of late, the Gaggs clocks are still very expensive refurbished items. Not new!

I spent over £550 with Gaggs buying the complete clocks, cables and drive box kit for my 650 twin. The speedo needed 4 repairs in its first year of use. The rev counter gearbox leaked oil from its cable end and worse still from the alloy plug in its gear end. This was held in place by a  solitary split pin which allowed it move and then half drain my oil tank.

For years I have  stripped my speedo gearboxes ,washed out and re-greased.Never did find a grease gun head to fit my Wanner gun.     Someone must know the secret  , would be nice to be able to grease the KS and brake spindles too.

I seem to remember last time I bought a speedo gearbox (from RGM a long time ago)  I had to open out the hole to fit the top hat washer.

Also...those hardened screws for the cover...I drilled new holes adjacent to the old and used Stainless self tappers from a yacht chandler. The cover is now rotated about 3mm, but it still allows the sleeve nuts to be easily reached. In the cover the original holes are of course still used so no change is visible.

I have found a photo of the Gaggs rev counter drive, This shows the dodgy points. You can even make out the wobby end bung held by the split pin. Gaggs were very good and repaired the speedo free each time but blamed the damage on the drive cable........which they had supplied!!!

Because I was running-in my rebored barrels, it was months before I twigged the speedo was not able to read above 50mph. The second repair was due to the clock face comming loose and destroying the pointer and stop/rest pin. When the clock was returned it waved between 50 and 70mph while cruising at 60. Illegal,  hence a third repair required which lasted all of 800 miles. I headed for Mr Pople after that.

Meanwhile I had purchased  an old clock off eBay which worked fine but was not as shinny as the rev counter.