Honda 200X Rear Master cylinder......please help!

[gearhead5150]

I purchase a 1985 Honda 200X. I have really enjoyed working on it and bringing it back to life. My rear master cylinder was frozen so, I drilled it out and ordered a rear master cylinder kit on ebay. When it arrived, the piston is bigger and looks diffferent. I contacted the seller and actually got to speak with them on the phone. They verified that the kit i recieved is the correct one for my 1985 Honda 200X.
I had read somewhere online that there is some confusion concerning the kits for this trike.

Please help! I'm confused and bummed.

I'm attaching a photo of the two pistons side by side. of course, the dirty one is the used one :)

please help!

Gearhead5150208797

[shortline10]

I believe that new kit is for an 86/87 200x .... take the part number off the bag and check for your self with a quick eBay search