03-17-2020, 11:59 PM
Just addressing the topic of exhaust noise, when I got my CB the original owner had installed the full Yosh exhaust system. The salesman revved it in the parking lot and it popped, which he apparently thought was a cool selling point.
I told him I'd buy it if the stock exhaust came with it. Next day the stock exhaust had magically been unearthed, I bought the bike and the stock exhaust is still hanging in my shed. I disabled the PAIR and the popping on decel diminished drastically but it still did it on downhill deceleration.
As the popping is caused by unburnt fuel igniting in the exhaust, it is not a surprise that premium fuel, which burns at a slower rate, makes it worse. Or better if you like popping. It is also an indication that this engine was designed to run on regular fuel as recommended.
An interesting thing about the modification of installing the exhaust cam on the intake side is the noise on downhill decel changed to a muted burble. So the fuel mix is being burned more efficiently. I suspect it is because it doesn't get as much fuel to begin with, because of the difference in cam profile, as also indicated by the reduction in hp on the dyno.
SO, the snarl went away and the popping went away, the things that were supposed to be desirable traits by the design team and the used bike salesman. I suspect some of both may come back when I get my finished product in place. I am waiting for the cam man to receive my cam so I can find out what he thinks. Also waiting to hear from Guhl on my computer. So I have bike parts spread all over the country in the midst of a global shutdown. Fingers crossed.
As a side note on exhaust noise, Google Mini Cooper exhaust burble, the forums are funny as heck (to me).
Ben
I told him I'd buy it if the stock exhaust came with it. Next day the stock exhaust had magically been unearthed, I bought the bike and the stock exhaust is still hanging in my shed. I disabled the PAIR and the popping on decel diminished drastically but it still did it on downhill deceleration.
As the popping is caused by unburnt fuel igniting in the exhaust, it is not a surprise that premium fuel, which burns at a slower rate, makes it worse. Or better if you like popping. It is also an indication that this engine was designed to run on regular fuel as recommended.
An interesting thing about the modification of installing the exhaust cam on the intake side is the noise on downhill decel changed to a muted burble. So the fuel mix is being burned more efficiently. I suspect it is because it doesn't get as much fuel to begin with, because of the difference in cam profile, as also indicated by the reduction in hp on the dyno.
SO, the snarl went away and the popping went away, the things that were supposed to be desirable traits by the design team and the used bike salesman. I suspect some of both may come back when I get my finished product in place. I am waiting for the cam man to receive my cam so I can find out what he thinks. Also waiting to hear from Guhl on my computer. So I have bike parts spread all over the country in the midst of a global shutdown. Fingers crossed.
As a side note on exhaust noise, Google Mini Cooper exhaust burble, the forums are funny as heck (to me).
Ben