Over the course of a year’s racing a 600 will ‘go off’ – due to the nature of the high revs run they tend to wear piston rings and lose compression as a result. Top end horsepower is affected, but much more is lost in the mid-range and your punch out of corners really suffers. And as we all know, the speed you get out of the turns dictates how fast you’re travelling at the end of the straight…
Even though covering a relatively low mileage it’s been in for a complete engine refresh; we’ve measured up all the internals, tidied the valves and valve seats, re-shelled the crank and fitted new piston rings. It was making 112bhp at the back wheel – it’s now putting out a much-more-like-it 125bhp.
Adrian also complained about a gearbox fault; this turned out not to be anything to do with the ‘box, more a hair-trigger quickshifter set-up which he was catching with his foot.
Note that the older Cordona quickshifters are adjustable for torsion, so you can set the amount of pressure needed. The newer versions use an electronic strain gauge that measures the amount of force at the gear lever, and is equally adjustable.
This ZX-6R is refreshed and ready to race; 125bhp at the rear wheel
