Balanced or unbalanced headrers?

Don't overlook the obvious:

TWO MORE places for exhaust leaks to occur.

I read that the headers for black caps and pea shooters are also differrent, black cap headers make pea shooters point out apparently.

The ballanced headers should be used with standard Blackcaps because of the higher back pressure. Well that's what I've been told, never used either for long.

Cash

What about the size of the header pipes. Is it an improvement to go to 1 1/2" rather than 1 3/8"

I have already decided to use that sytem on my bike, with some 1 1/2" peashooters.

Nigel

I don't see how 1/8" is going to make any kind of noticable difference

Not saying 1 1/2 is better or not than 1 3/8 but it's about 20% more surface , that should make a difference.

The interesting thing is bigger isn't always better. I don't see it making a lot of difference on a street bike so go with what you enjoy.

Leo Goff says the larger diameter pipes help . He likes the Viking inch and 5/8 's . I couldn't afford those so we're going with a set of 1.5 's I got for a pretty good price .

Ron

I think a "balanced" exhaust should be done quite a bit differently than what was done on the Norton and Triumph of the time. Just putting a pipe between the two exhausts probably had no effect at all, it looks totaly wrong to me and a flow bench would most likely prove it. The only thing it did was probably drop a couple of db which was all they needed to pass stricter noise standards. Cheap and easy, governement happy, bean counters happy, no drop in power so no complaints from the users.

I think a balanced exhaust would most likely look like what Dustall did back then, two into one into two. Look at what Jim Comstock did on his FI bike, he has headers going to a large collector under the bike and the collector exhausts to two big mufflers, THAT looks right.

Jean

In the early 70's Dunstall offered a similar system for Commandos and Triumph , but with a flexible balance tube . He claimed an optimistic extra 5HP at 5500rpm .
Looks like the bike in the pic. had his decibel silencers .
Note the reduction in diameter below the balance pipe :

Price was a hole 11£ .
(sorry for the low quality . my sun confiscated my scanner )

The last few lines of the ad say "This balanced system is not as efficient as the Power... " so even they admit this system is not very good and Paul Dustall was always very optimistic in his power claims.

Jean

jean ,
it's not an ad but a pic out of his catalogue .
The complete sentence is :
"...not as efficient as the Power system on page two but the improvement is still quite marked and worthwhile ."
He refers to his Dr Blair 2-1-2 sytem , for wich he claimed a 10 HP gain : 70 HP (!) at 7000 rpm .
For his balance tube system he does not claim an increase in peak HP , but 5 at 5500 rpm , which implies a substancial increase in torque .
both claims seem pretty wild ...