2024 6 into 1 options?

[CBX-tras]

The main reason that I use the stock head pipes on my builds, correct back pressure and aesthetics.
None of the aftermarket exhaust people make them as tight to the motor.

[Jeff Bennetts]

I’m partial to the Bassani 6 into 2 into 1, it made more power than the D&D, it also has a small I.D. at the head pipes like the D&D but the Bassani has a deeper throatier sound.

IMG_0011.jpeg

IMG_3033.jpeg

The pipe on this 80 is an original Bassani which has an end cone and has a very throaty, not raspy sound.

The other is a chromed reproduction without a cone.

[SanDogDewey]

The best sounding CBX I ever heard was Ray’s (Fastspider) with a Shule pipe!

[bobcat]

Bob, as you have done a lot of research and have unique plans for an exhaust system with different ID pipes, you probably know the stock double wall tube ID ?
[/quote]



No, I haven't had the chance to pull a tube to measure it yet. I wound up in the hospital before
I got a chance to get some hands on either of my Xs and had to depend on my wife mostly to
take measurements but I know the ID is really small.

It's not just the ID to focus on but the lengths. They both work together and there's a balance
that makes the tube work best.
Most of my experience comes from working with 4cyls but applies to the 6 but the six presents
some new and complex challenges. I can hardly wait to pick up where I left off.

[512tr]

It is a lot of research, theories, myths and discussion surrounding the exhaust system.

I think the most important thing in order to find the ideal exhaust is to design a system with the ideal size, shape and length that gives the highest exhaust velocity with minimal resistance (back-pressure)….and work well throughout the whole RPM specter.

I don’t think back pressure itself is a positive thing, but by physics it goes hand in hand with velocity….so it is unavoidable.
Exhaust heat also plays a role in maintaining velocity through the system, a double wall header will maintain the exhaust heat better than a single wall and bring the exhaust out faster.
Wrapping single wall headers will help to maintain exhaust heat.

But in the end the CBX exhaust on its mighty six is a matter of look, esthetics, performance, drivability, sound, and cost.

Hope your health recovers fast so you can go back to your workshop and continue your interesting project.

[CBX-tras]

Back pressure is critical to the proper operation of the CV carbs.

Not an issue with any type of direct lift or throttle blade carbs.

[bobcat]

Bob, as you have done a lot of research and have unique plans for an exhaust system with different ID pipes, you probably know the stock double wall tube ID ?

Different ID pipes? Mine will be different (slightly) from stock but all 6 tubes will be
the same ID but different lengths in pairs. Heat? The goal is to get the heat out and away
from the chamber as much and as quickly as possible. When it comes to back pressure, study
the venturi effect and what it does to flow velocity. The narrowest point of a venturi is where
velocity is the greatest. However, the longer the narrow point is, the more it begins to inhibit flow
especially as rpms climb.*
Back pressure is beneficial depending on where and how it's used and the configuration of
the collector.

All this "research" is just an accumulation of things I've read, questions asked and the good fortune
of having known Dave Rash (D&D) for 40+ yrs although I just began to start quizzing him about exh.
sys. stuff about 4 yrs. ago when I showed him the collector I came up with. I'm sure there were
plenty of times he was quietly laughing a me.
Originally I wanted just to build a 6-1 sys. that looked the way I wanted and wouldn't hurt power.
One thing led to another and I wound up hoping to build one that worked better too since I couldn't
find an old D&D anywhere. It's turned into a near vertical learning curve with a little of my own
conjecture added. I won't know if I accomplished anything until a sys. is finished and tested on a bike.

[CBX-tras]

A retired GM, inline 6 cylinder expert told me that the best sounding exhaust would be constructed with cylinders 1 & 6, 2 & 5 and 3 & 4, each pair joined in a collector and exiting into 3 separate mufflers.
This is true for most inline 6's of any make or model. (car, truck, bike).
Is it a coincidence, that's how the CBX ignition system works?

[bobcat]

Note the stock sys. the tubes are paired by length exactly that way only not collected
into one collector. Instead they are joined (pro link models) by the crossover tube for
better low/midrange power^.
Whatever silencer (megaphone, cannister, straight pipe,etc) doesn't seem to matter
as much as the collector forward as long as the ID is no smaller than the collector exit
ID. My preference would be a single silencer.

^accompanied by 2.5 deg. advanced intake cam timing.

So many things to do that all add up.....

[512tr]

Back pressure is critical to the proper operation of the CV carbs.

Not an issue with any type of direct lift or throttle blade carbs.

Please explain back pressure vs CV carbs ?

[CBX-tras]

Not too much to explain.

If there isn't sufficient back pressure, they don't work and when you crack the throttle the motor stumbles and dies.

[bobcat]

Not too much to explain.

If there isn't sufficient back pressure, they don't work and when you crack the throttle the motor stumbles and dies.

With all due respect, it has little to do with EXH back pressure. CV (constant velocity) carbs
depend on port velocity which increases with rpm. It's port velocity that lifts the slides. Since the
throttle/cables on CV carbs open the throttle butterfly, if you crank it wide open at low rpm,
the port velocity isn't sufficient to lift the slides right away and the still closed slides act like a
choke causing an over rich stumble until the velocity catches up with the wide open butterflies.
If you open the throttle enough to build some rpm/port velocity/flow and then crank it wide open,
the bike leaps with no stumble because there's sufficient port velocity to immediately lift the
slides. (demand)
With non CV carbs where the throttle/cables directly open the slides, there is no dependency on
port flow/demand from the motor. If you crank the throttle wide open at low rpm you still will
experience a brief lean bog because, with no butterflies and the slides wide open, you're getting
all air flow until port velocity/rpm catches up enough to get the fuel to flow.*

*this is where you get into the differences in atmospheric pressure in the top of the float bowl
and the carb throat/port. Atmosphere press. in the float chamber remains constant but as the
throttle is opened, slight vacuum at idle becomes total vacuum. Which way do you think the fuel
will flow ? From the float bowl via the various jets to the carb throat/port.

Are you confused yet/still ?

Man I'm slipping. I described the "slight" and "total" vacuum just backwards but as the throttle is
opened the atmospheric press. difference between the float chamber and the carb throat becomes
more pronounced and the attempted description becomes even more confusing I wish I could
find where I read the description about this.

[Syscrush]

Does anyone have advice regarding getting one's hands on a Schüle system? I know that they've been discontinued for a long time and they were expensive even when in production, but setting aside price, what would you even do to find one?

[banjobill08]

I got mine a few years ago, but made the initial enquiry a few more years before that direct for schule, from the first contact I heard nothing back, so I just gave up, then a year later he contacted me saying he would only make them with a minimum of 8 and he put me on the list?
Then 2 years after that he contacted me again saying was I still interested, I said yes, he went through the options he had available, I went for the special version and I paid upfront.
Nearly 2 months later I took delivery of the best looking systems for the cbx and worth every penny.

[Jeff Bennetts]

Do you mind telling us what you paid for it?