The CB1100 Community Forum

Do I get to say Helmholtz resonator again? Cause I like to say Helmholtz resonator!

Not Helmholtz but Helmut holds

(09-18-2020, 05:07 AM)The ferret_imp Wrote: [ -> ]https://en.wikipedia.org/wiki/Tuned_exhaust

Thanks ferret. I also read the link to exhaust scavenging. This part "The purpose of a 4-2-1 exhaust system is to increase scavenging by merging the exhaust paths of specific pairs of cylinders," makes me think that the "2" part of the equation is merging cylinders differently from what I was envisioning. Also, the information about primary tube lengths and diameters is fascinating--making me realize that there's a heck of a lot of engineering involved in designing an exhaust system, and that drilling holes, removing stuff, swapping parts, etc. could have a huge negative effect on engine performance if you don't know exactly what you're doing.

Yea that's why I trust the engineers and dont make many changes to modern Japanese motorcycle that aren't strictly for aesthetics.

If the 4into1 system is more efficient , how come dragsters just have straight out pipes ?

Because dragsters are all about raw power, not efficiency.

With belt-driven blowers and Nitromethane, the only purpose for exhaust pipes is to get the still-burning gas out and away as quickly and safely as possible.

(09-20-2020, 11:28 AM)mrichi_imp Wrote: [ -> ]If the 4into1 system is more efficient , how come dragsters just have straight out pipes ?

I took the exhaust system off my '81 CB750F just to see what would happen. It was so loud, it sounded like a helicopter.

(09-22-2020, 03:03 AM)Paris_imp Wrote: [ -> ]

(09-20-2020, 11:28 AM)mrichi_imp Wrote: [ -> ]If the 4into1 system is more efficient , how come dragsters just have straight out pipes ?

I took the exhaust system off my '81 CB750F just to see what would happen. It was so loud, it sounded like a helicopter.

BLOP BLOP BLOP BLOP BLOP BLOP BLOP BLOP BLOP BLOP BLOP BLOP BLOP BLOP BLOP BLOP BLOP BLOP BLOP BLOP BLOP BLOP BLOP BLOP BLOP BLOP BLOP BLOP BLOP BLOP BLOP BLOP BLOP BLOP BLOP BLOP BLOP BLOP BLOP BLOP BLOP BLOP BLOP BLOP BLOP BLOP BLOP BLOP BLOP BLOP BLOP BLOP BLOP BLOP BLOP BLOP BLOP BLOP BLOP BLOP BLOP BLOP BLOP BLOP BLOP

It does not sound as if the bike runs well , it missed two BLOBS !