| ZRX1200 Main Features - Engine |
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| If you didn't know any better, you'd be excused from thinking that bumping up the big ZRX's displacement to 1200 wasn't such a big deal. Just bore it out a bit, stroke it a few mil and slap on some new decals, right? Wrong! The new aluminium cylinder with its bigger bores is wider, necessitating wider cases, a longer crank, a wider head and valve cover, and a whole slew of other new components. In other words, we went to a lot of trouble to make a bigger, better ZRX. And the first time you whack open the throttle on the new bike you'll see that it was well worth the work. |
| Engine Features |
| Awesomely powerful, liquid-cooled, DOHC, In-line 16-valve Four now displaces 1,164 cm3 via an increase in bore and stroke from 76 x 58 to 79 x 59.4 mm. New, plated, all-aluminium cylinder weighs approximately 1.0 kg less than the earlier steel-liner cylinder while offering improved heat dispersion and longer wear. New cylinder head has oil return holes added between the cylinders for quicker, more efficient return of oil Cam drive sprockets moved 3 mm outboard to compensate for the wider cylinder. Engine cases, cylinder head and cylinder head cover are correspondingly wider, as well. Overall engine width increased by about 5mm. New cam timing complements the increase in displacement and contributes to increased power and torque across the rpm range. Four Keihin CVK36 carbs equipped with K-TRIC deliver sharp throttle response at all rpm. Digital electronic ignition delivers hot sparks at the ideal timing. New, double coned disc springs (diaphragm-type) in clutch housing enhance clutch action and make for smoother low-rpm operation and easier shifting of the 5-speed transmission. New, all stainless steel exhaust system (replaces earlier hot-dip aluminium-coated steel unit) reduces corrosion. Balance tubes eliminated from header pipes; muffler angle changed to be parallel to bike centreline. Engine side covers and cylinder head cover finished in bronze colour for improved appearance. |
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| New concave pistons give a highly efficient bi-convex shape to the combustion chamber. New crankshaft with inertia and balancing to suit the increase in displacement and the larger pistons. |
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