Exhaust system impact?

[MEHall]

How important is it that the resistance in the exhaust system is correct on these CB 650 motorcycles?

[jcasey007]

Since I fitted a MAC 4:1 system instead of my open cherry bomb, the bike starts, revs and idles better than it has ever done, so I would say yes, back pressure on the CB650 is important.

why this is I cannot tell you

[MEHall]

That's ok! it's the answer i kind of wanted.



That is my bike and those muffler pipes are the kind that usually fits on a Harley Davidson.
The trouble is that my bike sneeses now and then on idle with those mufflers.

[cb650]

If you want to keep those pipes and it generaly runs good try backing out the mixture screws or one size bigger idle jet. Maybe a new air filter too

[MEHall]

Well i dont like those mufflers at all, to short and noisy and they are making the axle bolt dirty.
And those 2 mufflers are made to fit the 1200 to 1300 cc HD engine.