OKAY - since nobody here REALLY knows the answer i went to the SOURCE.
the difference is not the bore - not the shark groove - the novarossi turbo crank has a WIDENED INLET port -
"Aurora Tentori" <email@example.com>
To : <firstname.lastname@example.org>
Subject : Re: Could SOMEBODY at Novarossi PLEASE answer this question????
Date : Mon, 7 Apr 2003 14:18:29 +0200
as for the information about the difference between turbo and normal
shaft, please check on our web site English version, Engines, Nova line, 2,1cc
where some of our engines are displayed. If you click on the picture of
the engine, the most important parts of the engines itself are present and
comparing en engine with turbo shaft to one with normal you will see the
Furthermore shaft 15611 has a wider inlet (aspirazione maggiorata).
The way we call our engines is maybe sometimes confusing, but once you
know the logic we use to call them (see my previous e_mail), everything
should be more clear.
The may of making the setting of the carburetor is not present in the
handbook but if you give a look to our web page, you will find there an
explanation about how to do it.
If any other problem, please advise.
> -----Messaggio originale-----
> Da: Cyber Toolz [mailto:email@example.com]
> Inviato: luned́ 7 aprile 2003 5.42
> A: firstname.lastname@example.org
> Oggetto: Could SOMEBODY at Novarossi PLEASE answer this question????
> I MUST have an answer to this question; what is the exact DIFFERENCE between the two turbo cranks that
Novarossi makes for the RS12TS1 and the RS12S1TR?
>RS12TS1 is a turbo engine with turbo glowplug, turbo underhead and turbo shaft;
> - RS12S1TR is NOT a turbo engine.
> After RS12 in the part number you can find following numbers or letters everyone of them has a specific meaning:
> T/nothing Turbo or normal
> S/R Indicates the type of carburetor (Slide or rotary)
> 1/2 Type of shaft (1 stands for serpent and 2 stands for standard)
> TR Means Truck (front ball bearing with tubber shield and bigger head for a better cooling)