450r rear master cylinder

[79vwrabbit]

The 88 250R I'm working on right now has a very rusted rear master cylinder. It got some serious water/dirt in there and made a mess. I'm starting to doubt that my Service Honda rebuild kit will be enough. The ones on ebay that are in my price range don't look very promising either. Does anyone happen to know if the 450R rear master would work on my 250R? (I'm sure somebody somewhere has tried this already.)