Exhaust back pressure concern....

[Brendan W]

One chart is not going to cover more than one specific motorcycle. What bike/engine is it for and what were the details/operating conditions? Those numbers aren't really a surprise, inlet pressure is maximum 14.7psi (in a perfect, theoretical world) so increasing it by 1psi is significant whereas exhaust pressure is much higher so increasing it by 1psi is much less significant.


Mark

Indeed. The people who did the work hung out a Loughborough University under the auspices of the Department of Transport Technology. First print was 1936.
I doubt very much it was a motorcycle. More likely a pushrod car unit.
Remember Hardy Kruger in the original Flight of the Phoenix ?

[GS1150Pilot]

Not sure how this would relate to your CB900, but I have a header of unknown origin on my GS850, and have a K&N filter insert in the stock airbox. I have not done official plug chops, but I have reduced the main jets from 125 to 120 (115 is stock). Needles have not been shimmed, pilot (mixture) screws are all in the 2.5 to 3.0 range.

Any weight reduction from the header installation has been GREATLY offset by installation of the fairing, saddlebags and trunk.
The bottom line is that I have a utilitarian classic GS that happens to sound pretty good, I don't care if it's a bit slower or faster.

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Yeah, I get you, Steve. I love the look of the stock exhaust on the CB900f-always have; and it sounds great, period. I may skim the head a bit, and if it needs an overbore, I'll likely go for the 985 kit. But I want it to look stock aside from a few details I am thinking about (possibly doing the wheels in the darker of the two tank stripe blues, a bikini fairing and light from the 1100 painted to match, etc.).

[Steve]

Yeah, I get you, Steve. I love the look of the stock exhaust on the CB900f-always have; and it sounds great, period.

Click on the link in my sig for my 850. The header looks rather stock-ish. The sound is a bit like a Honda Supersport with a factory 4-into-1 pipe.

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