Interesting;
"The FE 250 and FE 350 are powered by extremely compact DOHC units, which distinguish themselves by their free-revving nature and smooth power delivery. As their bigger brothers, they are equipped with a Keihin fuel injection system with a 42 mm throttle body and integrated temperature and altitude compensation. The injection is, of course, individually set up for each displacement and, using the mapping switch from the PURE TECH range of accessories, provides the option to adjust the motor characteristics to the rider’s individual requirements.
The engine cases for the new 450/501 engine generation are manufactured - as they are on the FE 350 - using a high-pressure die casting process, resulting in significantly reduced wall thicknesses but with the same stability. Thus, together with the weight savings on the piston, connecting rod and balancer shaft, the weight of the engine could be reduced by a whole 2 kg. Due to this significant reduction in the rotating masses, the handling advantage of the previous 70° engine layout was able to be more than compensated for, and a conventional engine layout once again used, which also provides the following additional advantages:
more compact engine allows a more compact overall layout of the bike
simplified routing of the header pipe eliminates undesired heat input onto the tank and airbox
bigger airbox capacity
reduced intake noise
lower centre of gravity of the engine and bike
An overview of further improvements to the engines:
New, robust, approx. 250 gram lighter clutch with wear-free steel cage, integrated damping for less transmission wear and a new pre-load mechanism for easiest operation thanks to a diaphragm spring (FE 350/450/501, TE 250/300).
Significant reduction in the vibrations of the 4-stroke engines due to lower oscillating masses
Optimised oil circuit with two oil pumps for the 4-stroke engines
An oil-cooled alternator with a capacity of 196 W provides a reliable power supply for the injection of the 4-stroke engines, as well as for the other electrical components.
Optimised cylinder heads, specially adapted for each displacement version, with titanium valves (FE 450/501: outlet valves made from steel)