Your options are
(1) Get a thinner tire
(2) Get a thinner chain. I use this really strong BMX chain, it gives me more room for the rear tire, it won't break and it won't get twisted after extended use, also, it seems to go through my engine sprocket with less drag than the bulky 415. --->
https://www.bike24.com/p272230.html
Also here--->
https://www.starbike.com/en/wippermann-connex-chain-1r8-complete-nickel-plated-112-links/
(3) Remount engine at a different angle.
(4) Get some kind of sprocket adapter that will move the rear sprocket away from the hub.