Topic: Well I'll be ... confused

[70CB750]

I treid to muffle the sound little bit more and made a new plate.

The exhaust is very simple, just an insert with holes in it and the idea was to use a new plate with smaller holes.  See the pictures.  The black plate is the original plate and the clean one is new.

Long story short, I am back to the old plate.  She felt like somebody is choking her right around 3800.  First I thought I am out of gas or something, she just would not go to higher rpms.

And yes, it is like little Johnnie doing science in his backyard  - but I would never believe the difference it makes. 

[brooze72]

If you are restricting the exhaust more would you need to change the air/fuel mix?

[70CB750]

Frankly, I don't know.   I suppose it builds up back pressure and that's why it works fine in idle and low rpms but not for the not-even-WOT.

The sound with the plate with bigger holes is not bad, and I will stick with it now that I know the new plate does not work. 

I will do some reading, but there is just too much going on for a thorough research.

[ekpent]

Have you ever tried wrapping the baffle with fiberglass or other materials to see what happens ?

[70CB750]

I did with just straight through perforated pipe and it did not do much. 

[flybox1]

If you are restricting the exhaust more would you need to change the air/fuel mix?

Yes, you create a RICH condition when increasing back-pressure.
Just as you would create a LEAN condition when going to a (more) open exhaust

if at 3800rpm you feel less power, you might drop your needle position a notch, and see how she flies.
(sooty/wet plug chop will confirm RICH, while recreating that 'choking' condition @ 3800)

[70CB750]

Thank you, would it have some gain to it?  Like better mileage?  I might mess with it again one day if there is a good reason, the quieter sound is not that important for me and the effect was marginal at maximum.

[flybox1]

best way to quickly maximize mpg is to keep your bike in tune, tires properly inflated, and get the AF mix correct for your intake/exhaust config.

[lucky]

You will need to tell us what kind of exhaust and intake system you have to get any tuning information.