Novarossi have been showing off their patented main bearing for their engines, which will come in the new Keep-On .12 and .21. The bearing features a narrower centre ring compared to the outer ring and this not only reduces rotating mass for better acceleration but it also reduces back flow to the carburetor by having the outer run wrap around material on the inside of the crankcase preventing the fuel from getting past. The bearing will be eventually available with ceramic or steel balls and while it is only now available in the on road engines, with more testing it may become available for the offroad engines too.
For on road engines the new Keep-On .12 3LS is a 3 port long stroke engine which comes with this new main bearing. The Keep-On .21 9XLS again has the new bearing but is an extra long stroke engine which gives more power in the bottom end. This configuration was used by Dario Balestri and Keisuke Fukuda at last year’s World Championship in Miami. The other change is that the carburetor now comes with an 8mm venturi as per EFRA’s new ruling.
For offroad there is the new Roma .25 (4cc) truggy engine, which is a compromise between the torque of a .28 and .21 engine. Designed for US style tracks which are small and require power to clear the big jumps, it has super smooth power delivery and runs cooler than the 28 and while more efficient than the larger engine, it uses more fuel than a .21 but still gets 11 or 12 minutes run time. Available in March. The Bonito and Plus4 engines stay the same but they will offer a more cost efficient bearing configuration with steel/steel bearings in place of the ceramic/steel in the current versions.
Finally, as an optional for the offroad engines, there is a new carburetor which has improved internal volume efficiency which basically means that it now uses 100% of all the fuel that enters the carb. This is thanks to new internals that include the 7mm chamber where the fuel enters, as well as a new barrel and needle. The plastic carb gives an additional 30+ seconds of runtime and also gives a better feeling for the driver.