Hmmm by the power of Google I found this from another forum
"Public service announcement:
If you need to replace the sliding pin boots on your rear caliper on your Yamaha, you'll notice the parts aren't listed on the dealer's fiche. I laughed at my local Yam dealer when he said you have to replace the whole caliper body!
A quick shufty round the other manufacturer's fiches revealed a few bikes use the same Nissin caliper.
Here are the Honda part numbers for the rubber boots on the rear caliper:
45133-MA3-006 (Boot
45132-166-016 (Bush pin)
The front will be similar, Yam don't list them but the others do. I'll post up those later if anyone's interested.
Hope that helps a few of you."