That's good example of the problem of taking a "normal" open wheeler and putting a biek engine in. LONG chain
If you look at the OMS - and all the designed ones - it's a much shorter distance from final drive on the engine/transmission to the axle.
That long chain loses you time as it whips and stretches
Mind you I'd not want to run a short wheelbase OMS on a large race circuit. Hillclimb "straights" are usually <100 yards