Topic: Question for the experts about aftermarket exhaust

[Stev-o]

Question for you experts:

Can an aftermarket exhaust alone increase hp?  I have a nice Kerker on my K6 but really see no improvement [according to my butt dyno!]

And BTW - cleaning out my storage, I have two CB750 exhausts for sale...

  http://forums.sohc4.net/index.php/topic,187562.0.html

[shameful plug]

[turboguzzi]

smart ass answer: define "increase".... 0.1 hp or 10 hp?
that said, the hp increase will be meaningful if coupled with other mods, just by itself, might do very little, good chance to loose low and mid range..
BUT, and its a big BUT, an aftermarket exh can bring big weight reductions, good for acceleration, handling, braking.
the livelier sound is a plus or a minus, depend son you, were you live, your neighbours...

[scottly]

Reply #167 on the exhaust thread that's stickied on the main forum has a dyno shoot-out. As far as weight savings, I recall a stock K7 exhaust with the mounting hardware and finned clamps weighed about 45 pounds, compared to the Winning exhaust at about 14 pounds.

[754]

Most of the dyno or 1/4 mile comparisons  showed gains.
 And yeah the weight thing is a big plus...

[PeWe]

I did not feel much extra when my K6 got a brand new RC 4-1 1980.
Stock engine with stock filter.
Many years later I understood that I should have raised the needles one step from K6 middle setting.
After that increase main jet to 110-115.
I increased main jet only and might have missed the middle range power.
But 4-1 gives generally not extra at middle range, right?
More at higher revs.

Off with 4-4, on with 4-1 made bike lighter and therefore quicker.

[754]

Yes , my bike ran pretty good with Hooker 4 into1. Ran it a while , with maybe 115 jets.. then one day i put 120ms in man did that ever help..

[TwoTired]

Can an aftermarket exhaust alone increase hp? 

Yes, at or near redline with a corresponding jet change.

Cheers,

[newday777]

Yes , my bike ran pretty good with Hooker 4 into1. Ran it a while , with maybe 115 jets.. then one day i put 120ms in man did that ever help..

My 75 that I bought from a friend's estate 4 years ago still has the Hooker on it that I sold to the original owner in 1976. A bit dented on the bottom pipes from bottoming out on speed bumps..... I had it barking the other night...

[754]

 Do you still have the Invader wheels ....a member on here was looking for a set a while back

[newday777]

Do you still have the Invader wheels ....a member on here was looking for a set a while back

Yes still running them....but have toyed with selling them for the right price.....

[754]

I sent a PM with info..