Cycle News - Archive Issues - 1970's

• months or so, and it keeps on sparkin ' without fail. The point block collapsed on our testee the first" day. The previously hot ·s e t · u p was to immediately aim the points at the - trashcan and replace them with Bosch components. It probably is still a good idea if your stock ones don't make it. 95% of them are just fine. Like eggs. That's about it as far as chronic problems with a 400 CZ. The low chrome content steel 4140 frame doesn't break. The still air box is well positioned. The brakes. which have been encased in conical magnesium hubs longer than most people knew what the words meant. are the lrest on a motocross bike. Everybody who rode it praised them no matter wha t thei r particular preference in brands. It's uncanny how fast you can go into corners. waiting past the point of prudence to gel on the grabbers and then slow down smoothly, very quickly with perfect control. Combine it with the wheel-lifti ng acceleration coming out and you start to understand how 10 win on this machine. The brakes work well even wet and gritty. The hubs are' laced to shouldered Akronts that, in turn, carry a 2.75 X 21 Barum on the front and a 4.25 of the same make on the rear. That rear Barum is an excellent tire for any application. The 2.75 really is too narrow for the h ard or s a n d -s ur Face d tracks encountered in the Southwest U.S. It slides out. The 3.00-3.20 Barum is a perfect replacement. The 2.75 is the mud tire and you guys who get to race in that stuff, hang on to it. They grip incredibly well and the rear tire has that nifty reinforced sidewall. The works bikes use exactly the same rubber as the production types. CZ chain. If it isn't the best, it's so close most racers will never know. Steel on bronze is the answer and it lasts and' lasts and ... well. almost everybody who can who races seriously uses it if it will fit their bike. Yours is included with the package. These subtle details of the CZ are what made the devotees of the cult in the first place. What are the faithful going to find in this model 400? They're going to find changes. The package is basically the '72 works frame, '72 works pipe with an inefficient silencer built in which destroys the original design of the pipe [intended for no-noise-limit GPs of a few years back), the same engine, and the '73 works seat. The frame is 'na rro we d at the cradle and holds the engine about an inch lower and %·inch farther forward. Thc swing-arm is barely longer with the el funko chain adjusters reversed from their previous direction, but the swingarm doesn't seem to Ilex and the swingarm bolt which used to loosen up has locktab washers on both sides. But the tab broke on oneofours and the swingarm bolt got loose. Oh, well ... The steering head angle is moved out just a taste to accommodate the longer travel forks, moved forward engine weight. and the innate geometric desires of a Czech engineer in the racing department two years ago. The result is that the new 400 handles quicker ... and slower. sort of. There seems to be more time elapsing from event to event but you just know and timing confirms that you are getting on and off that berm quicker and making turns that you didn't think you could with the old frame: at least not feel so good about it. "Old frame 400" riders didn't like the new bike at first. At last, they couldn't think of using anything else. The notorious CZ good handling is still there but it's different. Partially. because the bike's lighter (an honest 241 dripping wet race-ready pounds) everything happens so much easier. Combined with the vast available amount of throttle you can swing the rear end around a turn with the front end planted where you want it. It also slides well enough to deligh t a stone half-miler, But that's not usually the fastest way around a motocross track, you hot-doggers, The CZ 400 may be the easiest in the Jawa·CZ line to ride. It will always give you a second chance if you screw up. If you screw up again. Forks are stiff setting down but impart good control. The CZ makes you feel like Falta coming over a jump. New fork seals didn't leak at all and the forks retain the turneddown weight·saving feature of 73,/, models. well. you had your chance. The power is always there. Novices will find it easy to deal with, Experts will win on it at less cost than anything else in the class. But where were we in the classic CZ ritual? About up to the Carburetion Change Caper, if we remember right. Based on past experience, the best l\likuni set-up for Yurpeen bikes was the one developed by Valerian's Two-Cycle City conveniently located (for me) in W. Los Angeles. California. Based on present experience, it still is. The carbs are modified. a couple of manifolds machined and fitted to make it look like a works installation, and an envelope of Durable, dependable, you normally need only two more tools: a screwdriver and an adjustable wrench. But you're better off buying yours from a good competition dealer these days - just in case. Don't throw these new shocks away! They work pretty darn well unt it they are used up completely. You won't have to buy new ones for a while. Acceleration out of turns when you keep it on the pipe is very impressive. The 400 gets nearly all its power to the ground. jet, is presented to the buyer with the carb kit. It works right the first lime. Jerry Jardine. who even Jawa defers 10 in rna tiers of CZ-l\Iikuni mating. suggested first trying the 34mm size, the same intake diameter as the stocker it turns out. (The Jikov measures neither 32mm as was the case nor 36mm as recently promised in the spec sheet. ) It was a real naming pain 10 st art the 400 i f you overflooded the Jikov. Unfortunately, you knew you'd overflooded it if gas ran out. Tickle it til just before the gas runs oUI. Until you practice that a while. always unload from the truck at the top of a big hill. The 34 l\likuni allowed us C. t resters to bring oUI the throaty roar of the CZ with one deft kick, no matter who was watching. It also completely eliminated Installed Valerian's Mikuni carb kit made the CZ easier to live with. The 38mm size also made it one quick motocrosser. Looks clean, huh? Pipe will get flattened in a leftside lowside on a hard-baked track. Drill the shift lever to avoid buying a new layshaft if you bounce on that side. 4.25 Barum is fine rubber. the pipey surge on to the powerband encountered with the Jikov. On the other hand. you had to pay attention "10 whether or nOI you wer really in the powerband. The 34mm size increased tractability. made it a snap to start but the CZ wasn't appreciably faster and seemed to actually lose at high RPl\1 what was gained at low RPl\1. The lOP of third and fourth wasn"t as high. "Well." offered Jerry. "We also have a :l6mm and 38mm 1\likuni carb kit for the 400." Eyes widening. trying 10 appear off-hand about it, we muttered. "Can you put on the 38?" They could and they did and quite frankly. that whopping Mikuni turned out to be where it's at for this machine. The fuel intake nozzle was bigger than the Jikov's letting more pre-mix now 10 the float bowl. it still started second or third kick cold. and all the top end promised by the more cantankerous Jikov was realized. and then some. Man, this was a faaassst motocross machine. There was. unfortunately, no longer any good excuse for not being first into the first turn. Still 110 pipey-ness, still smooth, but it hauled and that carb was the only performance mod. For between $70 and $75 we'd subject our CZ to the same thing. It's a carb kit that works on this bike. The experts who rode it. whether or not they loved the handling. all thought it was plenty fast enough for them. The novices (that's most of us) liked the power surge from smooth-stow l o s moo t h - fa s t t0 s moo t homigodamighty. Like we said. an easy bike to ride. . We still believe in the Mikuni match-up part of the CZ cult ritual, like you re-read certain parts in good books (or look at certain pictures again, heh, heh.] And alt this goodness. all this no-nonsense racer comes to you at the increasingly attractive price of $1395 suggested retail, Models without the alloy tank are even less most places. That allows you to go racing right off if you're lucky and get one with a Filtron. Oops. almost forgot. You still have to throwaway the grips. That's $2. Still better than throwing away the frame like some others we won't mention for fear of reprisal. Everything else about a CZ works in a way that only a racing factory relatively unconcerned about easy marketing and advertising appeal can make it work. Handlebars are the most copied in the world. Seat to peg 1<> rider relationship is the best for the most riders. You can ride it sloppy and have fun or you can ride it rigorously and win. It is the kind of dirt racing machine that we must keep coming into this country or else the really good ones by which we measure a standard of excellence will dwindle. Even though il is still a CZ the old cult will inevitably die because of the differences. There will be a new cult made up of new CZ riders and of those who have never owned one. • Czech Specifications Frame .....Single downtlbe full cradle 4140 chrome moly steel Wheelbase Seat height (w1150 lb. rider) Handlebar width Ground clearance .. . 55%,/;6" 31" 33%" " 6+:. . . Forks: CZ with travel 7" 3~" Rear dampers: MX special w/travel " Spring rate 65 Ibslin. _ Engine displacement Bore x stroke Fuel tank capacity Clutch ." Transmission Final drive " .383cc " . .82mm x 72mm 2.1 U.S. gallons Dry metal multi disc left side selector 1·N·2·3-4 12.14 or 15tc/s sprocket; 52T rear sprocket Air filtration sometimes paper. sometimes Filtron Carburetion ...Jlkov 29-series. 34mm diameter Recommendedfuel .. 20:1 premixof90 octane . - !J'ls and CastroI 50 wt. Standard spark plug. Recessedtip PAL S14-15 Wheels: tires . . " "Conical Magnesium hlbs-w/ shouldered Akront alloy rims; 2.75 x 21 Barum MX front,4.25 x 18 Barum MX rear Warranty Sometimes 30 days Wet weight, ready to race Wesight distribution : Frontlrear Max. Horsepower 241 Ibs. 1101131 (claimed a cis sprocket 42 + 1 Max. torque (claimed) No claim

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