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******************ZYDECO RACING******************

******************ZYDECO RACING******************

Destroyed Gearbox
Hot Tip # 1
   Change oil frequently
especially if the bike is to be stored in an unheated space where it will go through hot and cold cycles which could cause condensation.

     Probably the most frequent cause of gearbox damage with a unit which originally functioned correctly is a worn, warped or maladjusted clutch.
    A worn clutch condition occurs over many miles as the driving and driven plates slip against each other as you engage and disengage the clutch. This is accelerated slowly over time as the clutch springs become fatigued which allows more slipping to occur.The driven(friction) plates are slowly abraded creating an acceptable amount of heat and nothing warps. At your clutch lever, the free play decreases over time requiring occasional adjustment to restore the correct free play. If all is well, with the free play adjusted, you can put the bike in gear on the center stand with the motor off and with the clutch lever pulled in you will be able to rotate the rear wheel with little or no clutch drag. These are all symptoms of a normally functioning clutch.
     In more extreme use, the same slipping and abrading occurs, but at a rate which produces excessive heat. This can be caused by racing, very spirited street riding, two up riding with lots of luggage or improper clutch use. This is why many racers use heavier clutch springs which reduce slipping during launches, high RPM downshifts and during any circumstance where the higher torque of a race motor might cause slipping.
     This warping has a very different effect at the clutch lever from normal wear. You will notice that your normal free play increases. This is caused by some of the components of your clutch warping or more accurately, coning. When clutch plates cone they become dish shaped and the surface area of contact between your driving plates(pressure plate with spring cups, intermediate plate and ring gear) and your driven plates(two friction plates) decreases dramatically and the coning accelerated due to even more slipping. There is no fixing this other than replacing the warped parts. Typically in a stock Moto Guzzi twin plate clutch this requires replacing both friction plates and the intermediate plate. The pressure plate and ring gear are thicker, heavier plates which are less prone to warping.
     The other effect of this warping or coning is that the stack height of the clutch assembly is increased. The stack height is the measured height or thickness of all the driving and driven plates. Since the ring gear is bolted to the flywheel when the stack height of the clutch is increased, all of the other plates in the assembly can only move forward including the pressure plate which increases the preload on the clutch springs. Eventually, when the coning becomes severe, this forward motion of the stack "coil binds" the clutch springs or otherwise uses up the available travel inside your flywheel and you can no longer adjust your clutch lever to give a complete disengagement. If you stop the bike in gear, you will feel it wanting to creep forward. When you clutch the bike to shift it, the clutch shaft and main shaft will not slow down to help sychronize shaft speeds with the lay shaft and you will notice cluncky shifts and slamming into gear. This damages the engagement dogs on your gears and sliding muffs. Eventually, you will have missed shifts and the bike may jump out of gear as well.next page

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