Cz250
CZ250
Lightness Is A Relative State - Relative In This Case To A Triumph
Cycle World Road Test
IN A TIME when the entire industry is in an almost maddening state of constant change, a stodgy attitude, such as several European manufacturers are known to possess, is just about the worst detriment a corporation can have. The Europeans have had to learn that the Americans, at least, won't buy machinery on the basis of previous records if the equipment is dated or
simply not competitive. This is particularly true when the price is generally above that of the competition. CZ is one company that has taken the cry of the American consumer to heart. And the new 250 CZ is the machine that has come out of this aroused corporate awareness.
There are four major improvements over previous CZs which will undoubtedly have a marked effect on sales in the highly Japanese-conscious U.S. market. First, and most needed, is the five-speed transmission. Second is the new Jikov carburetor. Third, the Akront rims, and finally, the new 250 CZ comes with a silencer welded onto the exhaust pipe.
The transmission is what is going to sell this new CZ to those who wanted a CZ before, but found themselves hesitant, especially after taking a test ride. The old four-ratio box just couldn't keep the two-stroke Single up on the pipe. Although CZs are torquers, there is still a point in the rpm scale where they operate at a higher rate of efficiency. The new transmis sion helps keep the engine within this operating range. But four-speed CZ riders need not fret. The new gear clusters can be fitted into their four-speed cases. It is also possible to install an older four-speed unit in the new engine, although why anyone would desire to make this swap is beyond us. The transmission exchange cannot be done, however, without some minor modification of the inner cases. The gear cluster in the `74 model is 1.5mm wider than the four-speed unit. Thus, it is necessary to machine 0.75mm from the cast bosses on each case. To install an older transmission in the five-speeder's cases requires the fabrication of two 0.75mm spacers.
Both transmissions are identical in design and are operated from the left side. A shift fork guide plate atop the cases moves the forks into their proper position for each gear. This plate is used instead of the more conventional shifting drum. Once a gear is selected, a pointed detent pin slips into a hole in the left-hand guide rail, holding the shift plate in position.
There are two major advantages to this type of transmission arrangement. First, the shift plate cover can be easily removed to check the transmission, eliminating the need to split the cases to do a routine check. And also, the shift forks, shift guide plate and shift fork shaft can be replaced without having to tear the engine down.
The 32mm Jikov carburetor (2mm larger than last year’s), on the 250 CZ is as good as any you’ll find on an European motocrosser. Formerly, the Jikov was one of the first things, along with the rims and shocks (more on them later), which a new CZ owner would toss downwind. The carb would constantly flood the engine if the petcocks were not shut off before killing the engine. And, should you fall during a moto, well—forget it. You wouldn’t get it started until next week. This made the CZs crankcase drain plug imperative. But this carb is different. The Jikov now makes starting a stone-cold CZ a two-to-four-kick affair. Not like a Yamaha, but definitely 100 percent better than before. Out on the track, the Jikov carbureted smoothly, allowing the rider to use the grunty power of the bike to come out of corners.
Although CZ claims that the five-speed has the exact same porting as the previous year’s model, the new bike felt stronger than CZs we’ve ridden in the past. The fact that the machine accelerates faster can be easily attributed to the extra cog in the gearbox, but the engine just felt stronger at all rpm. This, we must conclude, is due to the carburetor’s improved operation. There is one more factor that must be considered, though.
For ’74 CZ has gone to a radially designed sunburst head. The new head has much more finning area than the squarish looking topper of old, resulting in a cooler running engine. The head cools so well, in fact, that the factory G.P. bikes are cutting away every other inch on each fin in order to save weight. This drastically reduces the head’s heat dissipating ability, yet the GP. bikes are not having any seizure or overheating problems. Unlike the transmissions, the cylinder heads are not interchangeable. The new head is fastened with six bolts, one more than in the past.
The CZ’s wide range of power is transmitted through a set of straight cut primary gears to a unique clutch. The multi-plate unit is dry! This is the only motocross machine that we know of that uses a dry clutch. The beefy unit worked flawlessly throughout our test and it will probably deliver just as well for quite a while. It really felt strong.
The single downtube/split cradle frame on the Czechoslovakian scooter is strong. It’s manufactured from mild steel; lots of it. This massiveness is where the chassis derives its strength. Unfortunately, this also increases the weight of the machine. And the CZ is not an exceptionally light machine to begin with.
Little has been done to pare weight on the 250. Everything is designed to go the distance. And if that meant more weight, then so be it. The only items that are specially manufactured from lightweight material are the magnesium brake hubs and backing plates. But even then,their size almost negates any weight savings, although the binders are superb once broken in.
Air filtration is handled by a Filtron-type element inside a very well protected still-air box. The airbox breathes from just below the seat and is protected from mud and water by a shroud in front of the lower portion of the rear fender, and extended seat upholstery material on the side and front, that act like flaps.
This year, all CZs will come equipped with Akront rims. In times previous, the purchaser of a CZ would have to stop at an accessory shop on the way home from the dealer and pick up a set of these hoops. It was almost mandatory, since the softer steel rims the bikes came with, after about six potholes, looked like Stars of David.
To get the CZ singing its throaty tune didn’t take much work. Tickling the float bowl until it overflowed, then shutting off the petcock, swinging out the kickstarter, and tromping on it twice usually did the trick. The kickstarter is unique in that it has a built-in safety latch that works much better than the spring-loaded detent balls found on so many other bikes. To release the lever it is necessary to push directly downward on the shaft and rotate the top half of the arm to the desired position.
There are only two drawbacks to the system. First, should you stall the machine in a tight corner while racing, or if you should slide out or crash, you cannot hook the lever with your foot and swing it out. You have to manually disengage the latch. Second, since the lever is on the left side of the bike, you must dismount to effectively use your heft on the starter. Hopefully, you won’t have to worry about the falling down part because, as we discovered, this new CZ is a good handler.
To begin with, let’s say what we have to say about the shock absorbers. They’re rotten. They detract seriously from the machines stability in the rough, and when the going gets really bad, they’re downright dangerous. But the fact that the shocks don’t work as well as the rest of the machine doesn’t keep people from buying CZs. A CZ purchaser knows that he had better install a set of aftermarket shocks if he expects to compete successfully. Konis seem to be the best way to go. At least that’s what we’re told by the CZ owners we’ve talked to.
Once we got accustomed to the fact that we were going to get slapped in the rump everytime we hit whoop-de-doos, it was fairly easy to compensate. But the front end was altogether different.
With precise damping and spring rates, the long-travel front forks’ plush ride almost made us forget about the way the rear > end was misbehaving. The rougher the track surface, the more you appreciate the fine fork action. Chattery washboard corners could be taken as though they were smooth. On semi-rough turns such as those, even the shocks worked well.
The 250 CZ is not a berm bike. It will hold a given line like it was on a rail, yet the true fun of owning a CZ comes from destroying berms. The low rpm pulling power lets you fly into a turn deeper than the opposition, because you are heading for the berm and he is trying to turn, then square off the turn at the apex and power away spewing a roostertail of confused dirt.
Jumps are easy as the bike flies straight and true. But landings are harsh on the rider although the bike seemed none the worse for wear. We’ve ridden machines as heavy as the CZ before, but none that landed as heavily as the CZ.
Traction was never a problem when the terrain was in proper motocross shape. Barum supplies the tires that come standard on CZ motorcycles. The skinny 2.75-21 knobby up front grips track surfaces like glue. The only reason anyone might want something wider would be to protect the rim. Protecting the rim is what the rear tire does best, along with providing excellent traction, of course. The Six-Day-type Barum jets out at a 90-degree angle to the rim’s sides. This protrusion consists of a heavy build-up of tire rubber which continues part way down the sidewall. Its purpose is to make it possible to ride on a punctured tube without damaging either tire or tube. While you may think that his is great for ISDT but has little value in motocross, then you’ve never had a sure 100-yard victory snatched from your grasp by a last-half of-the-last-lap puncture. At least if you get a flat you can ride into the pits rather than push. And imagine the advantages if you were to find your tire pffft out in the desert. A 40-mile push would get you into top shape PDQ if it didn’t kill you in the process.
We would like to mention that American Jawa, which was going through relocation pains, could not provide us with a test bike. The CZ 250 came from Warren Burrell at American Motocross in Buena Park, Calif. Warren, who prepares some of the fastest CZs on the West Coast, was a great help to us.
To get the CZ off the starting line in pronto manner, 2nd gear is most effective. Revving the bike to some unheard of limit and dropping the hammer results in useless wheelspin. Besides, the CZ doesn’t like to be revved. Powering out at about 5000 gets you into the first turn quickest. Shifting with reckless abandon will get you into the first turn last. The steam-shovel sturdy transmission loves to be manhandled, almost brutalized.
When accelerating a CZ the best procedure is to rev it to where the power feels like it is going to peak and then, with your left toe hooked under the gear shift lever, try to knock yourself silly by smacking your knee into your chin. The resulting motion will engage the next gear and away you will once again go. Shift this thing hard. Cram gears, slam them home, beat the hell out of the gearbox and it will treat you right. But try to pussyfoot a shift and you’ll find yourself kissing your crossbrace as the engine revs wildly.
The CZ is a quiet motocrosser when compared to contemporary European equivalents. The built-in silencer takes the bite out of the exhaust’s bark without cutting power. The CZ 250 has superb front forks, good tires, excellent cornering manners, fine brakes, a transmission that can best be described as a masochist’s delight, and enough power to carry you into the winner’s circle. If don’t mind paying for levers that are welded to the handlebars, making independent adjustment impossible, a heavy overall weight and shocks that will have to be replaced, then you are a CZ man. Welcome to the club. |oJ
CZ250
SPECIFICATIONS
List price . $1295
