Topic: Stock 79 CB650 Exhaust note

[Pinhead]

After a ride last night (about 95 miles) I got home and figured I'd play around with the video recorder on my cellphone. I recorded the exhaust note/throttle response of my bike. I'm running an open air cleaner (stock filter), 102.5 main jets, and everything else is stock. The mufflers still have the Honda PN stamp on them.

Since this is my first real bike, I don't know if the throttle should be more responsive, or if the exhaust should be louder/quieter/lower, etc. Any comments from my fellow SOHC4 owners??

[DammitDan]

My 650 has about the same throttle response time.  Not super quick, but not slow either.

And I can't tell from the video cause the sound on it is pretty bad.  But I do remember the stock exhaust on my bike was pretty quiet.  The MAC 4-1 fixed that.

[Pinhead]

Did the MAC 4-1 force you to re-jet? Did it help/hurt power any? I'm honestly considering some slip-ons for the stock headers (or maybe have someone weld some decent collectors for my 4-2's).

I need to get a decent digital recorder so I can make the vid sound a little better... I think it sounds pretty good.

[cb650]

you guys remember the 79/80  had diff carbs than the 81/82.  So  jets are diff to begine with.





                                         Terry

[DammitDan]

No I didn't have to re-jet.

And I can't tell much of a difference in performance.  It's just looks for me.

[c_kyle]

My '79 650 has stock jets (to my knowledge), air filter, exhaust, original cables, etc.  The sound quality was pretty bad, but I think mine has a little quicker throttle response than that.  On the road, it takes off when I roll the throttle.  The exhaust note seems about the same; but it's hard to tell.

[c_kyle]

You're lucky, though; at least you have a good right side-cover!

[Ibsen]

I think Mac claims that you shouldn't have to re jet.

This is how my 80 sounds with a stock air filter (the lid is still on the filter box) and drilled mufflers.
LINK

 I forgot the check the main jet sizes when I had the carbs off though.
But the bike runs good. I rode it yesterday and it pulled strongly to 110mph, and I'm sure I could have have kept on for 10mhp more but the rider gave in before the bike.

[Pinhead]

I wasn't cranking it to WOT. That was only about 1/3 to 1/2 throttle. I know my accelerator pump jets are plugged, so I basically have no accelerator pump. That would incrase my throttle response. Going down the road, however, runs like a striped-assed ape. I have yet to find it's "top speed" because past 100 mph the thought of getting a ticket (or becoming an asphalt smear) bring me back to my senses.

I want to get mufflers that aren't necessarily louder, but deeper. Maybe straight-through glass-packs would work. There's a video somewhere on the forum that demonstrates straight headers; I love the sound, but it's too loud. If it were a bit quieter with the same sound, that'd be perfect. Any suggestions?