Exhaust Questions

[polyneux]

So here's my issue.

I got my 1980 CB650C in January of last year...been riding it, it works

I got it with 4 foam filters on it, not the box...and a 4-1 huge megaphone exhaust.....with no baffle.

I took it in stride cause it was a good deal...but now my ears are starting to hurt and I'm sure I"m overloading the engine in neighborhoods worrying about sound.

My first question is this...for a temporary fix is there a universal baffle that I could put in the thing to shut it up?

Here's more....I would like to go back to the stock 4-4. I've read that using the more open emgo type filters sometimes jetting, I have no idea if the carbs I have are jetted or not. If I get the 4-4 do I have to go back to the stock box immediately? If I have to do so and do so, and the carbs are jetted will I run into a problem. Should I be worried about individual carb tuning etc? I have never been into the carbs.


The engine runs without a hitch though. Idles around 950-1k and doesn't have any response issues that I can tell.

[cb650]

You can get a universal type to fit most 4-1 systems. Would be the cheapest. Jetting who knows. Put a muff on and try it. If it runns like shit go with a smaller jet.

[gojoego]

So you want to get rid of that 4 - 1 exhaust? I would defiantly be interested in it since mine is rusted through. Pics?

[quote="polyneux"]
Here's more....I would like to go back to the stock 4-4. I've read that using the more open emgo type filters sometimes jetting, I have no idea if the carbs I have are jetted or not. If I get the 4-4 do I have to go back to the stock box immediately? If I have to do so and do so, and the carbs are jetted will I run into a problem. Should I be worried about individual carb tuning etc? I have never been into the carbs.

[cgswss10]

Frankly I would run a plug chop asap to see where the engine is. One hint would be when you close the throdle and coast down, do you get backfiring? Doing a plug chop and letting us see your plugs would give us a better idea. If I had your bike I would fab a cap for the end with a "pressure tube" going back into the muffler. This would make the bike much quieter, but still give you the great sound (at lower level) I'm guessing you don't have tools or experience to do. You might look and see if you can get a supertrapp can you could replace the megaphone with.

What will happen to your jetting we have no way of knowing. Most likely the bike will run rich and you will find it will stop pulling and a lower RPM- like you won't be able to go past 6500 or something. Its a crap shoot because pods do crazy things to the tuning. you just have to make the exhaust change and see where you are.

It would be a good thing to do because open megaphones don't make people like motorcycles.

[The_Paragon]

I got a MAC 4-1 and thought it would be cool to run it open megaphone..

Yeah.. that lasted once around the block before I was annoyed.. I've since then cut 1/2 the baffle out.. Gives it a really neat tone, and its not loud.

[old gringo]

As for the "Loud Pipes Save Lives" crowd (mostly on big twins, you know who), I call Bulls**t. It's more about "Hey, look at me, ain't I cool?"
Glad you want to quiet it down. Your ears, and those of your neighbors will thank you