No clutch discs to replace so it can stay sealed for a long, long time. Not a lot of power. Same improvements available like for the 4 cylinder versions. Clutch version camshaft advanced a little to replace the little cam it comes with. Power depends on ring seal. You can resleeve the block for larger pistons and more compression. Easy upgrade is using the oversizes from Honda for the 450A. Clutch carbs are bigger if my memory is correct. Cylinder head can't be improved much. One thing that Honda improved when they went to the 450A version was using an external oil line to add oiling to a couple of areas of the camshaft to reduce wear. If you're doing a lot of miles, I recommend an external oil cooler. I'm a fan of the mineral based oils in it. Front springs are weak, especially for 2 up riding. You can get a few different rear shocks, but nothing affordable and significantly better that I've tried. Have fun with it.
