Make it quieter

1977 kz750b (twin)

I'm hoping to make my bike quieter if possible. I live in an urban residential area and want to start up 5am or so without the loud roar of my bike currently. 

PO cut the stock exhaust a few inches behind the crossover and installed short open mufflers. The thing is louder than I'd like for sure. 

I'm hoping to install a bend then mufflers in a more stock location as I feel my current mufflers are too low and loud. Any suggestions for the budget focused? 

 

cheapest will be probably finding a used stock exhaust locally. Cone Engineering has "quiet core" mufflers but they ain't cheap. Most aftermarket mufflers will be "cherry bomb" style that is a straight through slip on muffler, this type will not be quiet. if you want it to be quiet you will need internally baffling, not fiberglass wrapped around a perforated core.

I guess I should rephrase my budget comment, i don't mind spending a few hundred dollars for the pair. I want away from the slip on free flows and a cone would look better I think 

www.coneeng.com/pdf/motorcycle/MC-finished-Mufflers.pdf

No eBay APP ID and/or Cert ID defined in Kunena configurationI don't know anything about the Campbell mufflers linked.
Emgo & Helix Racing are a couple of other brands.
Dunstall mufflers would be another search term.

note: the dent in one of them may be for center stand clearance necessary on some models.


 

I'll bet those are obnoxious. Emgo commando type slip-ons would be a huge improvement and not too expensive. I have them on my cafe' bike.
Generally the longer the quieter.  Z1 Enterprises Mufflers

I see the muffler question has been largely answered  so I will add this: please install a front fender (or a fork brace) when you have a chance.

The stock front fenders include a very basic fork brace as part of their construction. Without the fender/brace the handling will feel a little vague and possibly wibbly-wobbly.

I once swapped a KZ400 front fender for an Airtech-type fiberglass fender and didn't enjoy the result. I suspect you have 35mm fork tubes, rather than the 33s on the 400, so the effect may not be as noticeable, but a fender is still a good idea. If you want to keep the no-fender look, then a fork brace would be helpful.

wrote:

I see the muffler question has been largely answered 

so I will add this: please install a front fender (or a fork brace) when you have a chance.

The stock front fenders include a very basic fork brace as part of their construction. Without the fender/brace the handling will feel a little vague and possibly wibbly-wobbly.

I once swapped a KZ400 front fender for an Airtech-type fiberglass fender and didn't enjoy the result. I suspect you have 35mm fork tubes, rather than the 33s on the 400, so the effect may not be as noticeable, but a fender is still a good idea. If you want to keep the no-fender look, then a fork brace would be helpful.

 

All very true!  The other advantage of having a front fender is that it keeps slop off your face if you ride through a puddle or rain.  Guess how I know.  Ed

 

No eBay APP ID and/or Cert ID defined in Kunena configurationNo eBay APP ID and/or Cert ID defined in Kunena configurationHelix Racing. 240-2500.
The Helix website should have info on them, but I'm pretty sure they have baffles that can be removed or repacked.

So I've narrowed it down to some options after taking some suggestions here. Decided to stay on the lower end after I ran the costs for the quieter core it just didn't make sense against the initial cost of the bike. 

Given these two options which would you pick if lower sound was the goal?

www.z1enterprises.com/yamaha-xs650-dunst...fler-wide-mouth.html


www.denniskirk.com/emgo/widemouth-univer...1336.prd/4401336.sku

I figure both will be better than what i have but I would like the quieter ones. And I'm confused about which would be quieter the version with repackable baffles or the non removable non straight through option. 

All things being equal I would go with the re-packable baffle. 
These are different lengths too. 

It is basically impossible to know which will be quieter on your bike without actually hearing them on your bike or an identical one. Some of it has to do with perception. An 80db sound at one pitch might sound louder than an 80db sound at another pitch to me, but not to you.

As a general rule, a longer baffle will be less noisy than a short one and a baffle with a smaller inner diameter will be less noisy than a larger diameter.

Of the two you linked, one has a chambered baffle, which is what the factory mufflers have, while the other is a straight through baffle with packing around it. I have a Holeshot system on my ZRX, which has a straight through, perforated baffle surrounded by packing. It is a fairly long muffler and baffle. It is a bit louder than stock at idle and small throttle openings, but not as much as one might imagine. Once the throttle is opened wide and the tachometer needle heads toward the red, quiet disappears, and the thing howls like a big dog.