Cz 250 Trials
CZ 250 TRIALS
CYCLE WORLD ROAD TEST
IN A PREAMBLE to a test of an honest-to-goodness observed trials machine last month we commented on the increasing availability of over-the-counter machinery for this burgeoning sport. As further evidence in support of this observation we present this month the CZ 250cc Trials. Throughout most of their history, CZ have been primarily concerned with building motorcycles for the European market, and with the exception of their worldbeating motocross machines they have striven to build low-cost, long-lived sporting machinery that double capably as to-and-from work transportation. The CZ Trials indicates that while they may be following that tack, they are no longer content with iust Euronean sales.
The CZ Trials is a multi-purpose motorcycle and appears at first to be a long way from being a true trials mount. Actually, the bike is deceptively trials worthy, and in one area - tractable bottom-end torque - the CZ is outstanding. The engine is based on the proven 470 series CZ sports model and it has been tailored for its new chores with a wide-ratio gearbox and an exhaust system that places the effective torque range at very low rpm. The unit-construction two-cycle single boasts nothing remarkable in its design. Ports are piston controlled. The connecting rod big end is fitted with roller bearings, while the small end uses a bushing. Three ball bearings, with two on the drive side, support the crankshaft. The transmission mainshaft is also supported by ball bearings, and the layshaft and starter/gear selector shaft employ bushings. The action of the five-plate clutch is positive and can be adjusted externally without removing a cover or plug. This feature encourages proper adjustment to be maintained and should go a long way to increase clutch life. Like all CZ-Jawa production machines, the Trials is equipped with the damnable "Slick-shift." This "helper" feature is not too bad on a roadster, but is definitely out of place on a motorcycle that, because of its intended use, will see a lot of deft manual clutch work. The result with this device is an uncomfortable delay when the clutch is feathered. However, the entire business can be done away with by any competent CZ mechanic.
The starter/gear selector is an interesting piece of engineering, and when one becomes accustomed to it — which is almost immediately — it's no bother at all. In fact, it's refreshing to be deprived of the opportunity of criticizing the location or design of a starter, either while in use or when stowed. For the trialsman this arrangement takes on even greater significance because he will be dealing with one less projection.
The torque-improving exhaust system, with clean large-radius bends in the pipe, is tucked well into the bike. The chamber is wide, flat, and with the retro-fitted exhaust pipe, pleasantly quiet. To those who have ridden observed trials, the benefit of an exhaust system that is quiet while the engine is "tractoring" is clear; few things are as fatiguing or will destroy concentration quicker than a loud exhaust note. We had occasion to ride the CZ without the exhaust extension and were greatly surprised at the difference. Not only is the exhaust quieter with the pipe, but low-end power is improved and the top end is much crisper. While we're on the subject of retro-fits, we would like to mention that CZ have "whomped" up a new air cleaner cannister that makes a considerable im provement in the engine's breathing. The previous item was restrictive and caused the bike to run rich most of the time., We view these two modifications as further evidence that CZ is after a portion of the American market. These are the type of changes that usually require a model-year of feedback before they appear on a production bike.
The single-loop CZ frame is quite rigid. Brackets and gussets are fabricated rather than forged and are made from rather heavy gauge material. The long swing arms are made from stout rectangular section tubing that re quires no reinforcing. They have been thoughtfully shaped to accommodate a wide section tire while remaining nar row enough at the forward end to fit within the relatively narrow rear frame section. The CZ Trials incorporates an innovation that has been common to Czechoslovakian motorcycles for some time; automatic lubrication of the swing-arm bushings. In its present form, the system com prises a nylon manifold and line leading from the rear of the primary case to the swing-arm pivot shaft. It's a sur prise to us that this simple, clean, efficient system is not more widely used. Fenders, tank and seat base are made of heavy gauge steel. For most applications, these com ponents are fine, but for the serious trialsman they are unnecessarily heavy. It will be a simple matter to replace the fenders with alloy numbers, and the standard seat will readily give way to a smaller saddle.
On paper, the CZ brakes appear to be more than ade quate. The front brake is indeed a respectable stopper, but the rear brake leaves something to be desired. It offers a soft pedal response, most probably because it is cableoperated, and pedal travel is restricted by the footpeg stub. The braking potential is there, all right, but it's going to take some careful adjusting to make the rear brake perform well. The rear wheel is mounted on three ball bearings with two of them on the drive side. It's rea sonably certain that, with proper lubrication and main tenance, these should last the life of the motorcycle. The rims are laced with heavy gauge spokes in the 36-hole. Continental pattern. Potential strength of the wheel assemblies is further enhanced by the hub design, which eliminates the need for a bent spoke head. The 1/2 x 5/16inch final drive chain is CZ's own, and has an excellent reputation in European motocross circles for being essentially light and staying together.
The electrics on the CZ are good. Both high and low headlight beams are strong, and the somewhat small taillight stoplight is reasonably bright. The horn is hearty and retains much of this at speed because of its location. One of the most striking features of the CZ is the labeled and color-coded circuit board inside the headlight nacelle. Forget the labeling and just match the colors.
Water and crud-proofing of the CZ is excellent. The mid-frame apron keeps all manner of things out of the air cleaner and battery well, in addition to stopping rearwheel-propelled mud and dirt away from the engine and rider. In addition, the homely little "mini-skirt" attached to the seat affords the rider with an increased measure of protection from bits of airborne ground.
Bars and controls are very close to being perfect for the average size rider. The bars are suitably flat for trials work, but just a tad short for most tastes. The throttle has a welcome slowness to it, and the clutch and front brake levers have almost the right angle for the standing position. Unfortunately, the lever mounts are brazed to the bars, and if the rider wishes to use his favorite set of "bends" or alter the control angle, he will be faced with the purchase of a set of new levers. The footpegs on the CZ are particularly endearing; the mounting faces are fluted and correspond to fluted faces on the peg stubs. Because the pegs are offset and two inches from center it's possible to alter peg height and fore-and-aft attitude by about four inches, in addition to several adjustments between horizontal and vertical.
The seat, which we panned for observed trials, is firm and comfortable for touring or trail riding. It will accommodate two adults in moderate comfort and further consideration is given to a passenger with a set of rear footrests, and, back to the trials rider again, these can be quickly removed without leaving unsightly holes. Speaking of things that are easily removed, the headlight nacelle, which carries most of the delicate electrics (light switch, circuit board, and voltage regulator), comes off with little effort and the stay-behind mounting ears can be folded inward or used as a number plate mount. This operation involves the removal of the speedometer cable from the drive socket, and while some may prefer to devise a threaded blockoff plug when the speedo is not being used, a simple electrical tape cover will suffice to keep the socket clean.
The finish on the CZ Trials is very good. Engine cases show a bit of as-cast skin, but the as-cast finish is quite good. Chrome, while sparse, is well done. Upholstery detailing is competent, in spite of the "old-world" pebbled material used. The CZ really shines — literally — in the paint department. The fenders are finished in white and the tank is enameled in a "no-apologies" orange that is one of the most handsome and distinctive colors to be seen on a production bike.
As an all-around motorcycle, the CZ Trials handles well, and as a trials mount it is quite good. It is a way away from being perfect, however. First, it is a bit heavy, and despite conjecture regarding what could be done with it, it must be remembered that the bike in question is the available item. Second, steering lock is not sufficient. This can be improved upon by removing the stop lugs in the lower fork bridge and "relieving" the tank to accommodate the fork legs. And third, the front suspension, while possessing a decent amount of travel, is a bit short on damping. This is particularly evident at speed on rough ground. Oddly enough, stability suffers little. An increase in the viscosity of the fork oil might slow down rebound.
Acceleration and top-end performance of the CZ are hardly sparkling, but this is an attribute rarely found in, and of dubious value, to a trials bike. Within its scope, however, the CZ Trials powerplant is just about without peer. The test bike has been repeatedly subjected to rock gardens, loose shale banks, hard off-camber hillsides, moss-covered muddy stream banks and hard-rutted dried clay. To each of these tricky surfaces it brings an almost universal solution; confident, patient power that soon has the rider looking for rather than avoiding the adverse.
CZ 250 TRIALS
SPECIFICATIONS
$595
PERFORMANCE
