First generation Ultra had some issues with its powerful engine. Some riders noticed the engines oil level rising, though no oil had been added. This happened since unspent fuel was being blown past the pistons into the crankcases, thinning out the lubricant. Kawasaki R&D dep. had never experienced such an issue and they related these symptoms to: a) prolonged low speed operation can contribute to that, b) fouled spark plugs, or c) loose belt tension can also contribute to the problem. Though Kawasaki had never focused or mentioned anything about the pistons or rings and the overall sealing. Ultra 260X is equipped with new pistons that feature redesigned crown and ring lands. These ones raise the compression ratio from 7,8:1(250X to 8,4:1 (260X) and the tighter tolerances make sure that no unspent fuel will pass through to find its way to the crankcases. The picture features the two different pistons with the 260X marked on the right.
