Hello thumper enthusiasts! A few weeks ago I asked Jerry Hanna if he thought anyone would be interested in sort of an informal report/article on the MZ Skorpion Sport; I thought it might spark some interest in this line of motorcycles. My only interest in MuZ (MZ for short) is that I bought one and I think they have a great product. I would like to offer some riding impressions, mention my likes and dislikes, maintenance items, and operating costs if anyone's interested.

Six weeks ago I set out to find what I could about a bike a friend of mine had seen in one of the local shops. He said it was a '500 Single' and thought it might be a 'Matchless'. He had been looking at Ducati's and wanted one real bad. He also knew how much I liked 'thumpers'. The shop that sells Ducati's had no thumpers, but I did get a chance to ride a Triumph 'Speed Triple', what a bike!, very fast and sure to win me some speeding tickets! Next stop was the BMW shop; no 'Matchless' bikes here but in the corner was two MZ's. I'd heard of them back in the 60's. Roadracing two-strokes, I think, from East Germany. I may have seen some of their road bikes in the Canal Zone, Panama where I spent my teenage years. These bikes were dwarfed by the BMW's on the showroom floor. After some discussion with the shop owners it was decided I would return the next day for a test ride. I took home some brochures and pricing for study that evening. Upon return in the morning I was also shown some other MZ models that had been sold and taken off the showroom floor. Those bikes all had Rotax engines. The first test ride was the Rotax powered 'Silverstar 500'. With both electric and kick start you have choice not offered much anymore. To use the electric start feature you must first pull in the compression release to ease the load on the starter. After a brief warm up I was on my way. The bike pulls good and likes to be short shifted. Higher rpm's bring on the vibration and doesn't produce much power. Restriced intake and exhaust keeps the bike quite docile. The Silverstar handles and brakes good; the gages are a little unusual in appearance, the oil and neutral light share the same bulb (I think this is the case). This bike brings back some old memories of the smaller road bikes I drove in the 60's, very utilitarian. It was pointed out how easy it was to work on. The Bing carburator has an air screw and a huge idle speed adjustment screw. Access to valve adjustment is great. The engine has no internal chains and the O.H.C. is belt driven. If my commuting needs were limited to in town I would have bought this bike. Others may feel like touring on this model but I need more engine and a larger frame.

Driving the Skorpion was different. You don't sit upright on this model, instead you hug the bike with your legs and lay down on the tank. This model can become an extension of your body. I felt more secure on the Skorpion and the power is more in line with my needs. I must commute to work mostly on the freeway at speeds approching 75 mph. I don't like driving that fast in traffic but you either keep up or get off the 'superslab'. The Skorpion has no problem running at 75 and still has plenty more to give. Engine speed is around 4650 rpm and redline is at 6,750. The manual claims a top speed of 109 mph (175 km/p). Braking feels strong, there's one disk on each wheel. I have not tried locking up the wheels but the front feels most sensitive. Front suspension is not adjustable with 4.72" travel; rear has a four position preload set up with 5.12" of movement. It's set at the least amount of preload and works fine for my 215 lb. weight. I have not bottomed out the suspension (yet) despite hitting some good potholes and one large 'city tity'. Tires are Metzeler's: 110/60 ZR17 and 150/60 ZR17 ME Z1 racing tubless. Dry weight is 416 lbs. and total weight permitted is 836 lbs. The manual claims the tank will hold 5.52 gal., but I find that hard to believe. I went on to reserve while out the other day with only 162 miles on that tank of gas. Reserve is supposed to be .92 gal.. My mileage has been between 45 to 55 mpg. Part of the problem with filling the tank all the way up is these new vapor recovery systems, you can not fill the tank all the way.

Because I'm not used to riding street bikes (most of my rides have been dirt and enduro bikes), I find first gear to be a little tall. I've stalled the bike several times while taking off, but the electric start saved the day quickly each time. Kick starting big singles in a panic (lots of cars behind you) is difficult at best. I like to short shift a bike (shifting at 3000) so second gear seems tall as well. Third gear takes me to 40, forth to 55, and top gear is good if you don't drop below 45 mph this is around 3000 rpm. I have no way of varifying the accuracy of the tachometer, however, the speedo is accurate a 60 mph. Power is good between 3500 and 5000 rpm's, I never have a need for more than 5000 rev's (80 mph). Vibration is slight, but there, and it varies depending on what gear your in and how much load is on the motor. This is the smoothest single I've owned. The only problem I have is numbing in my right hand from crusing at 55 to 70 mph. A cruse control will help a lot. Letting off the throttle in any gear causes an abrupt slow down so resting my right hand isn't done. Leaning forward all the time puts a lot of pressure on your hands and forearms. My arms hurt after a hour long ride, I'll have to get used to this. The seat is small and flat with not much padding. I haven't ridden long enough to see it becomes uncomfortable. The pegs keep my legs collapsed a bit but there is no vibration until 4500 rpm's are reached and then it's not bad. The worst bike I had for vibration was my '72 B50T. It would eat tailight bulbs ever 50 miles and break the corners of the license plate; it was still a neat bike though, with lots of low end grunt (long stroke). The Skorpion engine used is the Yamaha XTZ660. It has a five valve head (S.O.H.C) with dual header pipes and dual carbs. The left carb has a manually operated slide and the right is a vacuum secondary unit. Throttle transitions are smooth, there are no flat spots. This is the first water cooled bike I've owned so working around the radiator will take some getting used to. It's in the way when you have to adjust the exhaust valves. There are two tiny fans for cooling, I haven't seen them run yet, also, there is an idiot light for overheating which I will never see. This will require a buzzer or something to be added later for an attention getter or else.... Instrument lights are very hard to see in sunlight. Speedo and tach are first rate with large white faces. Riding is a blast, once off the line it accelerates fast with no noise, no high rev's, no fuss. I will have to do something about the noise, I want this bike to sound like a thumper but I don't want to anger the neighbors in the morning when it's off to work time. I'm open for suggestions. Re-jetting the carb's will be tough do to lack of room under the seat. Because the oil tank is under the back seat the battery and air box is crammed together under the front seat. I don't see a way into the airbox for a filter change. Oil in the frame is out of the question due to frame construction (no backbone under the tank), I think this will make getting to the intake valves and top of carb's easier. Shifting the five speed is clunky but clutch is smooth and progressive. My old '78 XT500 shifted much easier and I seldom used the clutch. Shifting this bike without the clutch is hard to do. Some of this maybe in the external shift linkage (used for peg position). On the XT (while driven off road) I would run the tach up to red line slightly ease up on the throttle and pull in the next gear with no clutch, it was real slick, my R5C and RD350 were the same way. The XT could really move but it would beat you to death after three or four hours of fast trail riding. It would climb the steepest hills we could find in first, second, and possibly third gear.

I think the Skorpion will prove to be a reliable, fun to own bike. I will keep record of maintenance items for anyone who wants them and provide part numbers for anything I buy (especially crossed over Yamaha P/N's).

Hello everyone! This is a good time to write this update because I've been able to do more pleasure riding here lately. The weather has improved drastically during the last few weeks here in north central Texas. I've taken several half day trips to some of the more seanic areas west of the Dallas/Ft. Worth area. The roads are well kept and there are lots of twisties and hills to ride through. For those of you who are familar with this area, I recommend the Glen Rose and Possum Kingdom areas for good riding.

I've only accumulated 3,500 kms. on the bike since last November, but I don't care much for riding in near or below freezing weather. I performed the 600 mile servicing on the Sport back in early November. It was easy to do, and because I took my time, it required about two hours to complete. I decided to do the service myself for two reasons: Become more familiar with the bike and save myself the 400 mile round trip back to the dealer that I bought the bike from. Some of you may be interested in what was involved in the valve adjustment so I'll touch on that a little. I do not have a shop manual, but I've been told by three MuZ dealers that one will be available soon. Before I started turning wrenches I called the dealer and went over the procedure for servicing the bike. They knew I would be doing all my own work when I bought the bike from them. For the record, though, I do not recommend you do your own service. Doing so may void your warranty and damage your bike. This artical is written for pleasure reading only, it is not intended to be used as a guide for any procedure, technical or otherwise.

To adjust the valves I did the following:
1. Position bike on centerstand on level firm ground.
2. Remove seats and side covers.
3. Disconnect battery leads (for safety).
4. Make sure engine is cool. I like to do this in the morning after the bike has sat overnight.
5. Make sure fuel petcock is closed and remove fuel line. MZ uses spring clips to clamp and secure the fuel line to the barbed fuel fitting. I re-used mine, but it would maybe a good idea to replace them; they are made of light gauge material and fragile.
6. Remove gas tank. Once away from the bike you can remove the petcock trap bowl and clean out the screen.
7. Before going any furthur make sure there's no dirt on the bike that can fall into the engine. I never pull covers off a dirty engine; clean first.
8. Remove spark plug cap and plug. Take care not to damage the spark plug wire when pulling on the cap. I used pliers to gentally twist the cap first. The wire is permanently attached to the coil. If the wire goes, the coil goes!
9. Remove plastic plug from left side engine case. I used a large screw- driver, so as not to damage the plastic.
10. Remove intake and exhaust valve covers.
11. The intake valves are easy to get to, thanks to the frame design. The exhaust valves are a different story. The radiator makes for close quarters. The sticker on the chain guard gives the valve settings. I did mine while the engine was at T.D.C. on the compression stroke. I prefer to set the valves a little loose, at the high end of the tolerance. Years ago it seemed that valves always loosened between adjustments. Now, they seem to tighten themselves. I guess it's from running unleaded gas, causing additional wear to the valve face and seat. On the other hand very loose adjuster screws can dish the end of the valve stems making proper adjustment impossible. On my bike two of the three intakes valves were too loose, I'm glad I did not wait any longer to do this. I used an old Honda wrench to keep the screws from rotating when I tightened down the lock nuts. This tool has come in handy over the years. You've probibly seen them in Honda tool kits; they're about 2" long round bar stock, slightly flattened and pierced on one end, cold headed for the adjustment screw on the other. They fit into tight spaces real well. I torqued the locknuts to approximately what it took to loosen them.
12. The exhaust valves were loose but not as bad as the intakes. Getting the feeler gauge into position amounted to poking around in the dark.
13. Before screwing the covers back on I cleaned off all mating surfaces and reused the old "O" rings. I have not had any oil leakage since doing this. I was careful not to over tighten the valve covers.
14. I put a few drops of oil on the spark plug threads before insertion. Its important to get plug cap gromlet in position to help keep dirt and trash from accumulating down around the plug. This stuff could get into the engine the next time you pull the plug out for service.
15. This is probibly a good time to check for loose hardware and binding cables while the tank is still off. Check your rear brake master cylinder and engine coolant fluid levels while your at it.
16. Install gas tank (don't lose those rubber supports that fit between the tank and frame tubes) and connect gas and overflow lines to fittings.
17. Replace side covers. The side covers are a blast to put on. Reconnect the battery cables and install the seats.

I followed the owners manual closly for the oil change procedure. The only difficult part is getting at the coarse filter. It's suspended above the countershaft sprocket and held in position by the hoses attached to it. You've got to hold it real good with one wrench while you loosen the front of it with another; this is all done in a confined area. I have to admit that I didn't want to mess with part of the oil change but I did find trash in the screen. I used Mobil 1 oil to replace the factory oil. I probibly should have waited until the next oil change to use synthetic oil, relizing that the engine is still braking in. However the engine runs smooth and quiet. I've read a lot of good things about using Mobil 1 in motorcycles and I will continue to use it in the future. The oil filter is a common part and used on several other Yamaha engines (XT500-600, SR500, Virago's, etc). There should be no shortage of these at the parts counter. I paid $7.99 at the MZ dealer; one of the local Yamaha shops wanted $10.00 for the part. The Dennis Kirk catalog has three different brands ranging in price. The Fram filter for $5.50 is probibly a good buy.

I checked the rest of the bike for loose fasteners. The owner manual says to torque the header pipes as well. The coolant level was low so I topped it off with a 50/50 antifreeze mix. One annoying area is the squeaking back break. I've looked it over and cannot find any problems. I may have to de- glaze the pads by sanding them lightly. Another problem area has been the handle bar position. A fellow owner out in S.F., Ca. suggested I swap the handle bars over. This involved some light drilling (for the switch housing pins) and replacing the 5mm screws that help prevent bar rotation; longer screws are needed (around 40mm or so). If you decide to do this watch the throttle cables! they're already too short, I noticed some binding after the swap. My hands were going numb after 15 minutes of riding, now there is no problem at all. The only downside to the swap is body positioning, I cannot lay down on the tank as before. I've read a lot of controversy on whether or not to lube an O-ring chain. I'm using PJ1 Blue Label chain lube and it does'nt fly off as advertised. I'd like to hear what other riders are doing to extend their chain and sprocket life. This may cause some flak but I've been using kerosene (home heating varity) to wash off dirty parts and loosen road grit. It's safer then '87 octane solvent' and easier on the skin.

I'm going to install a used Audiovox model AA 9127 automatic paging alarm on the bike this weekend. I bought this alarm for $99.95 at Pep Boys two years ago for one of my cars. It works great and is very compact in size. It has a siren output and I'm sure there is a way to disable the ignition by using a relay circut, more on this later. The main attractions are the paging feature and the low cost. I did check the unit for current draw (before considering its use) and found it to be .008 amps while idle and .56 amps (approx.) while transmitting. Signal output lasts for less than a minute so dead battery should not be a problem. The paging requires an antenna; I'll work on a concealed unit over the next few weeks.

All in all, the Sport has been very dependable and a more powerful ride than I expected. Starting the bike (with full choke) after sitting a week, requires a lot of cranking. Thats my only complaint. It cruises great at 70 mph, which is an indicated 4,100 rpm, and offers no vibration until you hit 80 or so. I've taken the bike to 95 mph, but without a good fairing, higher speeds are not practical for me. I'm getting a steady 50 to 55 mpg and can run 200 miles before stopping for gas. I recommend the MZ to anyone looking for a moderate ride with lower maintenance cost. Your insurance will be inexpensive as well. The Skorpion is not considered to be a high performance bike.