Honda CB 919 exhaust

I want to replace the exhaust system on my Honda CB919, which is a 2003
califonia model. I was looking at yoshimura, but it says their systems
cannot be used on california models.
Why? can I do it anyways ?

 

I would wonder about passing smog inspection with those pipes.
If you have someone who runs a smog inspection station, you could try
the pipes and if they don't do it, you can go back to stock.

 

Your stock exhaust system will have a warning engraved right onto the
muffler that says don't change the muffler. And any aftermarket exhaust
manufacturer will usually say that its exhaust systems are for "off
road use only", as if their customers weren't going to ride their
street motorcycles on the street with the new louder exhaust system.

You can do anything you want to, but just save the old system so you
can reinstall it to get the inevitable citation cleared off. One guy I
used to ride with liked aftermarket exhaust systems, but he didn't have
a way to get his stock exhaust sytem home after
he had a shop install a Kerker pipe. So he left his stock system at the
$tealer$hip.

After the inevitable noise ticket, he went back to the shop and asked
them to reinstall his stock system. But where was it? Somebody at the
$tealer$hip had taken it, so he had to buy a whole new system!

A new original equipment exhaust system is incredibly expensive! Just
the header on my Yamaha is $700.00...

Your state's laws probably prohibit altering the exhaust system to make
more noise or air pollution. And, your engine has been carefully
adjusted to run at its best with the stock system. Can you say "mid
range flat spot"? A 4-into-1 exhaust system will have a bad interaction
with the camshaft timing during the valve overlap period and try to
shove air *backwards* through the carburetors. So, from 5K to 7K the
engine may fall flat on its face if you install a 4-into-1 pipe.

Does that model have fuel injection or carburetors? The EPA has
mandated that the idle fuel/air mixture be very lean to reduce
pollution while the engine is idling in traffic. So the manufacturer
sets the carburetor idle screws very lean and plugs the holes so the
owner can't see the screws.

Knowledgeable enthusiasts have been drilling out the plugs concealing
the idle mixture screws for decades now. Then they just turn the idle
mixture screw counterclockwise about 1/4 or 1/2 a turn to get better
response as they just open the throttle. Maybe they install a pilot jet
that's one size larger. The motorcycle probably wouldn't pass a smog
test, but the owner can easily turn the screws back to the original
position. Reinstalling the correct jets requires carburetor
disassembly.

The aftermarket performance industry in America is a *billion dollar
per year market*. Enthusiasts are going to buy aftermarket exhaust
systems for the style and the idea that their machine is "customized"
to reflect their own personal taste, whether the modification actually
enhances performance or not.

Aftermarket systems are often ridiculously expen$ive, like I was
reading where one guy installed a $1600 titanium system on his Suzuki
that already had 150 horsepower at the rear wheel. He didn't add power,
he made the motorbike lighter and added some
"style", as he perceived it. But, to make the exhaust system lighter,
Yoshimura built the exhaust system to eliminate Suzuki's
computer-controlled exhaust throttling system (SET) which helps the
engine overcome the typical midrange flat spot.

Twenty years ago, you *could* get an extra ten horsepower out of an
aftermarket system. My GSXR-750 really benefitted from being
"uncorked".

But the motorcycle manufacturers have come a long way since then.
Sometimes an expen$ive aftermarket system only adds 1 or 2 horsepower,
or none at all. Re-mapping the fuel injection system does a lot more
for the power.

The main thing is the reduced weight. If the stock pipe has a mid-range
enhancing exhaust throttling valve like Yamaha's ExUP or Suzuki's SET
or a catalytic converter to reduce emissions, an aftermarket pipe
without those items will be lighter.

 

The 1200 Bandit does as well, but then that is also an old-tech engine.

 

Damn, I think you better move from the" left" coast. Here in NY I have
a set of Two Brothers cans on mine, no problem.