Originally Posted by teammpp
The MT12 was the Novarossi based Mugen longstroke. They followed it up with the MR12 shortstroke.
Sorry, but that's not correct.
The MT12 was a long ROD engine, not a long stroke.
It has the same stroke than the MR12, RS12 S and the N12LS.
If you take the cooling head off a MT12, you'll see that the entire sleeve sits on top of the crankcase and not flush. The rod is longer the same amount.
The only long stroke engines from NR are the RR12L3 (5) and the N12LL3 (5) and now the Plus 12-3
Long stroke means, that the stroke is longer than the bore