The Arctic Cat functions as a DFI engine at low speeds, correct? I wonder how the Orbital patents are affecting all of this?
The old aircooled open class mx's ran a lot of piston clearance and you could hear the piston knock until things warmed up. I've got an old Yamaha 400 in the shop right now and it's pretty noisy when it first fires up. I'm pretty sure piston metallurgy has improved quite a bit since those old SC500's.
It's "DFI", all the time. Though it does more than just put fuel into the combustion chamber - it's all written there.
It's a "different animal" entirely from Orbitals system.. A low pressure ( see 58PSI) system that is injected at multiple points in the rotation of the crankshaft / piston positions.
And the oil injection - oh yeh!. Into the cases, and also into the fuel rail / injectors, through to the little end, and all metered and timed. The 'right' oil ratio, at the 'right time'. Hopefully.
As I've written all along - there are so many alternative paths to 'DFI' 2ts. Orbital's, really found their "home" in 4ts - they are paid royalties / have licensing agreements with a vast array vehicle manufacturers.
Orbital's is a complicated system, that requires very high pressures. And, does not take advantage of / stay true to the "simplicity of 2 Strokes". Well suited for a 4t Car / Truck engine though.........
Get something like a Quaife Gearbox, and run a primary chain / belt, or gears, and you've a gearbox. I bet my arse that you'll see blokes doing this. It will probably be a Pom. They're crazier than Aussies, or even those Demented Kiwis. And, they still have Very Easy MOT ( rego) stds. At least whilst they can fight off the European Parliament and their legislative minions.
It's the sort of thing I expect to see in Performance Bikes magazine. They regularly feature very trick 2 strokes.
As for the piston - lets see - SC500s - round about 1974, or thereabouts. I think piston / engine tech and materials have moved on just a bit, in all the subsequent decades. I used to watch Brian Clarkson Road Race his SC500, when I was a teenager - I haunted him in his
tiny shop with the Rickman distributorship in Penrith in the 70s, then worked about 50 metres from his wreckers in the late 90s. A Gentleman and Right Royal Ratbag.
