81 Exhaust Headers Only, no pipes, no baffles. Power?

[Quinn_McLeod]

Hey guys,

So I'm running an '81 with stock headers, but with no pipes and no baffles. Just engine and headers (surprisingly, it's not THAT loud).

Am I losing power or performance? Some people say that motorcycles need "back pressure" created from the exhaust pipes or the baffles. Any truth to that?

 

[DogBunny]

It's not really back pressure, that's just an easier way to talk and think about it. What it really is is anti-reversion. Try Googling anti-reversion.
With short or no pipes you run a risk of cold air entering the engine after you shut it off and warping a valve.
Open pipes are called drag pipes for a reason, they are meant to maximize performance at wide open throttle, anything else, like the 1/8th to 1/4 throttle that 95% of street riding is done at and your performance will suffer.

 

[Quinn_McLeod]

Makes sense. I do plan on putting Harley Sportster straight pipes on to extend the headers, and then install baffles into those pipes at the end when I'm done.

 

[Quinn_McLeod]

Okay so has anyone used these mufflers? Are they any good? eBay item # 351044244622 Shorty Muffler. They seem cheap. Do they need baffles too?
I'd love some insight with these as I am looking to make an exhaust purchase this week.

 

[TwoManyXS1Bs]

Those usually have a removable baffle. Cheap, absolute minimum compliance with 'baffled muffler' laws of the '70s (if that still exists). On a budget, and if you must, they'll work. If exhaust sound is important to you, there's much better out there...

 

[gggGary]

My take; any muffler is better than none. I have an 82 with a "bit" more muffler than those tc's. They at least knock off that exhaust valve pop that sounds so cheap. Too loud for me, a set of stock pipes should be back on it today. the mufflers will be available. I don't understand "baffles in a straight pipe" thinking. Why would you want to install "worse than open exhaust" pipes?

 

[DogBunny]

I don't understand "baffles in a straight pipe" thinking. Why would you want to install "worse than open exhaust" pipes?

Because baffles in a straight pipe work and sound better than straight pipes without baffles.

 

[Quinn_McLeod]

Because baffles in a straight pipe work and sound better than straight pipes without baffles.

Agreed.
So here's my question then - Harley straight pipes (for look), but with baffles so they're not stupid loud and I can actually get some "performance" out of them - OR what other after market options are out there that are good?

Basically, with just the headers, I feel that the bike has to work really hard to keep up with the speed of traffic. Look, I KNOW it's only a 650, I'm not complaining about POWER, I'm just wanted to get more highway speed use out of it, and I think some mufflers would help. I just don't know what to get for best highway speed performance.

 

[gggGary]

These seem to work well; with foam filters in the stock boxes, BS34's mains up 3 sizes it's got a habit of overpowering the clutch at about 5500 RPM.



A bit loud for me but many would probably like the sound.

They tuck in nice and tight and don't interfere with brake or stands.