Motor interchange between years?

[dwnnout]

I just got a 2012 rt sm5 with only 2k miles on it. (Sold to me as a none runner) It has a spun rod... Looking to get another motor but I am not sure about what is years are interchangeable?? Any help would be appreciated.

[Peter Aawen]

Anything up to 2013 from an RT should work, altho basically any V-twin should fit; but if I was doing it I'd try to get the motor AND the ECU too, especially if it was a motor from anything but an RT, altho the 2013 RT's did get more low rev torque than the earlier tunes...

But please note well, the RSS's & ST's had slightly relaxed Nanny conditions when compared to any of the RT's, cos the RT's have a higher CoG & are a little heavier, so the Nanny for the RT's was set just a little less relaxed, & that might make a little difference in the limits of performance & braking...

Over to you.

[Chupaca]

have you looked into repairing the engine..? Nice opportunity to beef it up..

[Peter Aawen]

I've heard that they sell re-build & upgrade kits for the 'same motor, better tune' Aprilias, and it's not as tho Rotax motors aren't used in all sorts of machines & vehicles that rely on ultimate reliability.... that 're-build rather than re-place' might just be worth a look?

[billybovine]

Look for a RT SM engine from 2010 to 2013, RS or ST 2013 to 2016. They are all the same engine series. RS engines 2008 to 2012 are significantly different and would be a big job to make compatible.

Nanny programing does not reside in the ecm but in the vcm and would not change with an engine swap. So is not a concern.

[Freddy]

Look for a RT SM engine from 2010 to 2013, RS or ST 2013 to 2016. They are all the same engine series. RS engines 2008 to 2012 are significantly different and would be a big job to make compatible.

Nanny programing does not reside in the ecm but in the vcm and would not change with an engine swap. So is not a concern.

Just curious BB, what/how 'significantly different' is the early RS engine?

[billybovine]

Just curious BB, what/how 'significantly different' is the early RS engine?

The bottom end is the same. The differences starts at the heads. The RS has a larger combustion chamber volume. So lower compression ratio. The cams are different as well. Resulting in a higher peak horsepower. The big difference for doing an engine swap is the throttle body. The RS has a mechanical throttle connected directly to the throttle grip. RT is a throttle by wire. The ECM controls the throttle. The throttle grip is just another input into the ECM.