What clutch to use on a 116 smoker?

Birky. High initial cost, low long term cost. Paid 300 for used, fresh rebuilt unit, now going on 3rd season without failure or rebuild. Uses standard cr125 clutch plates I believe. Have also used 4disc tomar, good clutch also, but rebuilds are costly.
whatever clutch you decide on make sure it will handle a good bit of hp so if you decide to upgrade to a 125cc or bigger you won't have to buy another clutch, just trying to save you some money farther down the road...
Birky or an axle clutch. Higher initial investment but cheaper in the long run and even if rebuilts are not cheap you will spend more re building other clutches more often IMO.
IMHO - Tomar TD-43 or SMC axle clutch re-worked by Pudge Engineering or Horstman Big Sprint All run with j/s. Value/Dependability/all 3 appropriately tuned will handle Big HP and/or Heavy Loads w/o compromise.
We got ours from John Hilton used. Since 2009 we have put 2 sets of clutch disc, new seals and tungsten weights in it and have never had any issues with it. I would highly recommend it for the higher HP engines.