Saturday, June 6, 2009

Clusters

I mentioned the OVER works cluster I have.
In the past I have often recommended changing the XTZ shaft for that of the SZR in order to gain a longer 1st gear.
The two new engines mentioned in the last posting also have been changed. One of them has the SZR shaft and first gear, the other has an ex-MZ works racing cluster made by an east German machine shop for MZ. It differs slightly from the OVER.

Here are all four clusters:


You can see how rediculously short 1st gear is in the XTZ engine. Belgarda changed that for the SZR, leaving the rest alone. Both racing clusters are very different from stock, with extremely long 1st gears and close ratios. The OVER cluster is most extreme, being even longer in 1st and shorter in 5th. There are only about 800RPM between shifts which is perfect for racing but can be very trying in regular driving and downright exasperating in traffic. Speeds below 25MPH are only possible with a slipping clutch.
Having tested the ex-MZ cluster as well, I can say that it is only slightly better on the street. Both shift by themselves, fast and effortlessly, up and down without the clutch.
This of course has to do with the higher quality of the cluster itself, but more importantly with the small difference of speed between the two shafts. That is the reason why the SZR cluster also shifts better than the XTZ. The layshaft is driven by 1st gear, so the extremely low 1st of the XTZ makes the speed difference large. The slightly longer 1st of the SZR greatly improves the shiftability, and the extremely long 1st of the two racing clusters makes shifting nearly unconscious.

The OVER cluster is different in another way as well.

Here you can see both an SZR at the bottom and the OVER cluster at the top. You can see that the gears look different, and that 4th and 5th have coarser, stronger teeth and are considerably wider than the stock. The dogs are different as well.
The ex-MZ cluster does not use two different modules.

The OVER is no longer made and the ex-MZ was never offered as such. Reportedly, the machine shop which made them would make more if demand arose. Slipstream does offer an racing cluster. All of these, foremost the OVER, are or were very expensive. Slipstream also offers a shorter 5th gear.
More important though, for the "normal" Skorpion rider is the modification with the SZR shaft and 1st gear. This is a simple and worthwhile modification. For me a must-do.