Am going to have my sleeve replated as I have found some vertical scoring caused by either a cold seizure or debris in base. The piston skirt also has scoring so it will be replaced as well. This would obviously be an opportune time for an oversize kit such as the 420. Does anyone out there run one? ( my bike is a '99 400 )I was also wondering how it would affect reving ability and what jetting changes would be needed. I read here that the 400 revs easier than the 426. Is this so?