Carb question

I began tearing down my '77 250CR this weekend and had an unexpected suprise. When I took the airbox cover off I found that a mouse had decided to build his home there. He chewed up everything in there...filter, plastic on the filter cage, etc. Heck, it even ate part of the airbox and inlet to the carb. I never knew mice would eat metal..no wonder his old bones fell out with the rest of the crap. Grrrr, I hate mice. Now I'm going to have to replace the airbox and carb. I got an ok airbox from Ebay but am wondering what to get to replace the carb. The original is a Bing 54 but I think a Mikuni 38mm was used in an '78 250CR. Do you all think I should change to to a Mikuni? Would a new 36mm Mikuni be a good choice or should I try and find a 38mm? Any input would be appreciated.

Marty

I love BING's and if it were mine the Bing would stay but if hell froze over and I put a Mikuni on it I would go with a 36mm. It's really what ever YOU want to do with it. Now all the 38mm Mikuni fans can chime in now.

A 36 will give better low / midrange as compared to a 38.. unless you like riding a screamer, then go for 38,
A 36 isnt bad for a 400 bike either , so there you go.