Just my opinion... I think it would work fine. The 90 isn't a huge monster of a motor or nothing. A basic little muffler would be fine. I have seen more than a few of the 110's now with a small tractor muffler on them from the local Runnings Fleet & Farm store, they sound good and run fine with them. So anything is possible with some fabrication.
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1984 Honda ATC200ES "Big Red"
1982 ATC200E "Hondie"
1988 TRX300FW "Project Quad" Still in progress....