Since the 185s is essentially the same frame as the 200 series and the 200m has 25x12x9..I'd say there should be clearance under there for at least 25".
Of course you'd need to change rims too..if you change the hubs to a set of say 200x hubs you are on a standard 4/110 bolt pattern.
You could probably steal a set of rims and tires from a buddies Honda quad to test fit and trial ride. Then decide if you like what you feel.
Not a lot of choice on the 8" stock rims so not a lot of options to experiment with!
Current toys..
1986 Honda 350X..trail bomb!
1985 Honda 250SX..my main mudder
1985 Honda 250ES..Back in Black Trike
Current non-trike toys:
1990 Honda TRX300FW
1995 Seadoo GTX
1998 Polaris Indy Lite 340(Nearly new looking)
1998 Polaris Touring 500
1998 Club Car (electric)