right im currently on the home stretch on my nc24 build, today i got down to the gritty issue or rebuilding the front brake calipes and came across something the pistons in the calipers on my nc24 are 27mm and the seals i have been sent are 25.5mm and so the piston does not slide n easy and after being forced in is sticking on the pistons slightly and leaking on and off, so my questions is do i have odd pistons or have i got the wrong seals for it?? anyone have the right part number fot the 27mm pistons seals and dust seals??

cheers in advance guys

Are they genuine Honda seals?

The NC21 and NC24 both use the same caliper and it has only one size of piston / seal

Each caliper has two dust seasl that go on the outside (closest to the edge of the piston that presses the pads)
edges of each piston (2 pistons per caliper)

Part... 43109MA3006

Each caliper also has two piston seals.. these go on the inside of the caliper for each piston.

Part... 43209MA3006

Key thing when doing these calipers.. make sure the pins are clean and replace the seals for these and grease them with proper brake slider grease (orange stuff)

and use a smear of red rubber grease on the rubber seals and pistons when assembling.

The two slider seals are.

Part.. 45133MA3006 (Boot B)

and

Part.. 45132166016 (Bush Pin)

The two slider seals are imperative to be clean and new.. as they get old and if you use old grease they dont seal anymore.. this lets crap into them and the caliper cant slide as good so it either sticks on or off and you loose a lot of braking power... :-)

btw...

here is a guide I wrote up on overhauling the calipers.. (with pics)

http://www.jacksons-lair.co.uk/caliper.html

i'll try and reply when I can but i'm in Japan so bear in mind +8/9 hours..