My SZR is the second oldest one recorded in the owners list in Germany, Nº.132; the first 100 units were not exported out of Italy at all. International sales began with 101.
Since getting it, I have little by little tried to refine it and remove as much weight as possible without resorting to a hacksaw and angle grinder. One of the first moves was to replace the impossibly clumsy clipons with Gilles GP Lights like I was using on all my MZs. A Brembo adjustable blake lever was fit.
New solid pegs as replacements for the utterly impossible fold-up junk were made up using third party so-called racing pegs (so-called because such pegs are not legal in actual racing) and adapters I turned from stainless. The lower one for the right side, turned down for the brake lever. The left side without, since I use a reversed shift lever, first gear up.
Prisms for a ra ing paddock stand were fit using pop rivet-nuts.
A new CNC milled chain wheel with 43t was gotten from Sieg and installed with DID 520ERT2 chain.
By and by, nearly all bolts and nuts were replaced by either aluminum or titanium from Poggipolini. Both brake lines were replaced with steel braided lines from ABM, again with aluminum banjo bolts.
The front rotor was replaced with a Brembo Racing cast iron unit, together with Carbone Lorraine C55 sintered racing pads. Of course, the rotor is bolted on with Ti bolts, the caliper bolted on and also bolted together with Ti bolts as is the rear unit as well. Thankfully, the Yamaha (made in Italy by Belgarda SPA) has Brembo calipers to begin with.
The passenger pegs and their brackets were removed, the bike registered as a single seater. Those things are actually 14mm solid steel and really heavy. I found a CNC milled quick release fuel cap by TWM that fit the OEM (from Acerbis) tank out of the box. I hate those locked gas caps, especially when the ignition key has to be used. I guess this is a leftover from the racing days; race bikes don't usually have ignition keys.
With some convincing, I was able to get Glaeser to make and offer a bubble wind screen for the SZR.
After more coaxing and convincing, I was able to get a Termignoni cup exhaust, never mounted,much less used, from Heinz Weber who had bought it with the idea in mind of reworking it for his very special 14" Skorpion side car bike. Something he thankfully never got around to. When the SZR was introduced, a cup challenge was also started in Italy for which Termignoni made these exhausts which are very well made and light. Now that they are no longer made, they are very scarce and coveted.
With that mounted, I got a high-end can from SR-Racing, made for the XT660R. The can is big but it is also very quiet even though it does not have a DB eater inside. Well thought out and executed as one is to expect from SR.
The next step was to modify the cooling system. the the thermostat housing, filler, and some hoses were gotten off eBay from a YF600.
A T-junction, and hose clamps from a local supplier and a length of garden hose as well.
Unlike the SZR, grown-up Yamahas had a car-like two-circuit cooling system with a true thermostat which is shut when cold, routing the coolant back to the engine without going through the radiator. The "new" thermostat was placed in the center, the feed hose from the water pump to the engine cut apart and spliced with that T-junction so that the coolant from the thermostat, when closed, returns directly thru that garden hose to the water pump. You can see that both the return line from the cylinder head and the garden hose are both at the bottom of the housing below the thermostat valve. Only when it is hot enough, is the coolant allowed out the top of the housing to the radiator. The thermo-feeler for the thermometer is also in this housing so the reading is that of the coolant as it returns from the cylinder head. The modification is easily done, the parts cheap and it is well worth it. The engine now reaches 80ºC. with a few minutes and holds that constant. The original setup almost never exceed 60º except on hot summer days at traffic lights. 60º is too cold. Of course it is easy to block off part of the radiator and many do this to increase the operating temperature.
I left the engine untampered with - or rather I did only those things that required removing the side covers: I fit my lightened flywheel/freewheel assembly and of course I fit that solid balancer gear before something bad happened. The engine itself has never been opened as far as I know. there is no tuning save the lightened flywheel assembly and the exhaust.
I fit a SilentHektik Motocoil with BERU PowerCable as I am wont to do with all my stuff. I normally use a BERU 12-5DU plug, a very standard plug, no precious metals no nothing. Just good.
I usually modify the plug to a semi surface discharge type, a trick I learned from Tony at Silenthektik.
Of course, I also installed the (for me) requisite Ignitech Sparker TCIP4 set to a maximum spark advance of 29º and the limiter set to 9500RPM. Since finding out about Ignitech three years ago or so, I have sold at least 100 of these boxes all over the world. they are definitely worth it.
The big advantage is being able to set the curve so that one is rid of the chain lash etc. The engine runs smoother, in particular at the bottom end, but I revv this one regularly to 8500 in the lower gears and run it at a constant 7000-7500 in 5th on the Autobahn for 100 km at a time. Despite the stock engine, this bike, reduced from nearly 190kg to 167, is fast for what it is. It takes some nerve and more than a little tuning to be able get away from me. On the back roads, I seldom get out of 3rd, rarely into 4th, never into 5th. keeping the revvs between 6500 and 8500.
After loosing a nut on the rear axle despite using a torque wrench, I decided to revert to the old-fashioned style using a cotter key to secure the slotted nut, the pin itself secured with a length of braided stainless.
This is the state of the bike I wanted to sell. It must be obvious that I cannot sell this for going el cheapo rate. I offered for less with the original exhaust as well. In neither case was there any interest, at least no one inquired although I know that SZRs a constantly sought after.
I resigned myself to retiring the MZ to the attic for the time being. THe MZ is not for sale; it is a one-off bike.
Thus reconciled, I decided it was time to go for Gilles rearsets on this one, too. As mentioned above, the left side had been fixed with a makeshift. this would not do for the Gilles, so I made new part to be welded to the frame and took the bike up to my friend's metal fabricating company. Rolf is an artist with the TIG welder. Nevertheless, he had requested I wait until he had gotten his new AC/DC welder. Since most of his work is done with stainless, he normally needs only an AC welder, of which he has several. His large "Linde" AC/DC unit did not work to his satisfaction with DC, however, and he had ordered an array of new welders to the shop to try out. Then he called me up. We lifted the bike up with the crane onto the welding table (as we had with the other bike for the new exhaust), unhooked the battery, etc, and Rolf welded the new part on so that only someone really in the know can detect it. I lucked out in finding the exact same color in a spray can and the repair was finished, like new - better than new.
Gilles supplied me with 15mm sheet 6061 and I made up the two very different mounting brackets myself, the old-fashioned way, marking out by hand with scribe and square and centerpunch, drilling the holes and tapping. Only then did I cut out the outline at the bandsaw and finish with various files. then the two plates were milled to thickness from behind, there being a 3mm difference between top and bottom mounting points and Gilles' standard thickness being 10mm at the bolting pattern. Done, the brackets went to Gilles to be anodized. the standard parts were picked from the stock list as necessary and - voilá - my AS31GT4SU rearsets were finished. I am satisfied and Gilles is, too, that they look like they had been factory made. In drawing up, I had tried to keep to the Gilles style. As nice as they are, there will be no AS31GT4SU offered by Gilles. The two very different brackets are much too expensive for such a limited market.
I can supply the drawing and the parts if someone wants to make the brackets on his own. One person, admittedly a real SZR "nut", is doing just that at the moment.
And finally, I was fed up with undependable blinker relays and ones that might work at idle but not at speed. I got myself a "m-flash" digital relay from Motogadget and am rid if those problems.