Originally posted by patelladragger
i'm for sure you're right they are all made by novarossi. But they are different. I'm not a builder so i can't tell what is different about them - but something is because they run different. I have an rs12 turbo, it's more a top-end motor that needs to rev. My rb x12 3 port has the same specs but is much more punchy off the bottom. I had a mugen mt12 - it had the most punch of the bottom of any of them - but they're all novas. Maybe the timing is different - I dunno - maybe the experts around here can tell you.
I cannot say that the other novas are any less or more reliable than the RB, because I have not ran the dog out of them like I have these RB.
Engine life is mostly dictated by the % castor oil and the engine temp. My guess is that you're probably running them within the optimum operating parameters which should give you longer life out of the engines.
If you take a look at the crankcase, the crankshaft and the piston / piston sleeve of the 3 or more Nova motors, you'll notice that they are exactly the same. What is probably different (no expert here) could be the carburator. I was told that Novarossi carbs are slightly different than NovaMega.
Anybody can confirm this?
The MT-12 being a long rod type of engine, has the characteristic of being very good at bottom end. Short rod type motors like the RS-12 and RB X12 tend to give better top end.
That's the general rule but with mods and timing changes, you can make any motor do anything
On a stock unmodified motor, playing around with the low end needles (front and the rear brass screw) will give you very different characteristics altogether and will determine how strong your low and mid. I would think that is why your RB gives different kind of characteristics than the RS-12.