03-23-2016, 03:08 PM
Both racing motorcycle engines, and a lot of aeroplane engines (particularly non normally aspirated), run at high EGTs. Notice how your airplane engine's (that's a guess as I don't know the type) EGT rises when you lean out for cruise. Some cruising power settings are predicated on EGT. Some lean to rough and then richen the mixture a couple of turns. Leaning for climb is generally not recommended, at least below 3-5000ft. This results in a cooler EGT and CHTs than if you lean for climb. After full throttle height some manufacturers approve leaning for climb. This is a simplification but I am sure you will understand my thought process here. High stress engines with high EGTs and high CHTs but operated under standard procedures and well monitored.
Most aerobatic checklists mention M for mixture to full rich as the engine will be subject to sudden changes in operating temps and stresses. This mirrors the stresses induced in highly stressed motorcycle racing and super sport engines. But the beauty of a motorcycle engine is that you can lean for power, by EFI, and step off the bike if it falls apart. There are many reasons aeroplane engines have an inspection and maintenance cycle that would be prohibitive for a road bike. For a start, they are more highly stressed (P/W ratio is important in flying machines) and secondly you can't step off without causing some anxiety to those below
.
Racing motorcycle engines do run in the 1100 - 1300 deg range, or even higher, for their relatively short life. Standard road bikes run cooler. I would say that an engine like the CB's, relatively unstressed and purely oil/air cooled is designed to run fairly cool compared to higher stressed engines. Certainly below the 1300 mark and probably well below the 1100 mark for most of its life. I say probably cause I can't find that thermal image someone posted.
Cheers
Most aerobatic checklists mention M for mixture to full rich as the engine will be subject to sudden changes in operating temps and stresses. This mirrors the stresses induced in highly stressed motorcycle racing and super sport engines. But the beauty of a motorcycle engine is that you can lean for power, by EFI, and step off the bike if it falls apart. There are many reasons aeroplane engines have an inspection and maintenance cycle that would be prohibitive for a road bike. For a start, they are more highly stressed (P/W ratio is important in flying machines) and secondly you can't step off without causing some anxiety to those below
. Racing motorcycle engines do run in the 1100 - 1300 deg range, or even higher, for their relatively short life. Standard road bikes run cooler. I would say that an engine like the CB's, relatively unstressed and purely oil/air cooled is designed to run fairly cool compared to higher stressed engines. Certainly below the 1300 mark and probably well below the 1100 mark for most of its life. I say probably cause I can't find that thermal image someone posted.
Cheers