MZ/MuZ Riders

I thought it was about time I carried out the "de rigeur" Tzr wheel transplant. Managed to obtain these late Tzr250 (3xv) wheels, 3" x 17" front and 3.5" x 17" rear.



I had a measure up and a dummy fit which showed I needed a 17mm front spindle which was duly acquired. This allowed me to see the mod required to fit the left side Skorpion fork slider. This is basically a step up from 17mm to 25mm at the left of the spindle to allow clamping in the left leg.

Acquired a spindle and machined up a press fit aluminium sleeve which I retained with Loctite for good measure. Again, I was interested how great the weight saving might be.

Std 20mm Skorpion spindle


Modified (Yamaha) 17mm spindle


So a handy saving of 0.373Kg right there alone.

I'll update my progress as I go, but I'm waiting for fork seals at the moment.

Mark.

I got the Tzr wheel spindle and speed drive gearbox fitted, but the wheel was offset approx. 12mm to the right with the std Tzr speedo drive gearbox.
I wanted to maintain a cable driven speedo so decided to machine the drive gearbox to see how much this would help matters. I decided once again to weigh the thing before I started, more out of curiosity than any hope of losing much weight.

Std Tzr 250 drive gearbox


I machined approx. 6mm from both the gearbox body and the main internal driving gear in the lathe, recutting the slots with a hand held grinder.

Modified (narrower) Tzr 250 drive gearbox



So another 40 grammes lost to swarf or just over 22%. Quite satisfying but not enough to centre the Tzr wheel, I still needed to move the wheel to the left.

There was only one thing for it and that was to machine the lower left fork leg (slider). I had number of bites at this, machining a little at a time and rechecking until I was able to fit the wheel perfectly centrally between the fork centres.

Modified Skorpion left lower fork slider


I media blasted both sliders and got to thinking that perhaps a little more mass might be shaved from the sliders. As they are 100% aluminium this was unlikely, but I was able to loose another 65 grammes shared between both. What really surprised me was just how eccentric (throughout its length) the right leg outside diameter was to the machined bore. I machined just over 1.3mm from the o.d. of the leg before calling it a day and it still hadn't cleaned up the complete circumference.

Skorpion fork sliders lightly 'cleaned up' in the lathe


Progress has somewhat stalled for the moment whilst I wait for upper fork bushes and seals to arrive before the rebuild can commence. At least it should be straightforward with no more component modification required.

Mark.

Forks painted, rebuilt with new seals and bushes, and fitted up together with the centralized wheel with fully functional mechanically driven speedo .





Mark.

Awesome mod Mike, keep us (me) informed with the rear wheel mod.

Very nice indeed, though I have already junked the fragile mechanical speedometer in favour of a GPS version and in preparation for a wheel change (I don't drive through many tunnels).