Muffler Mod?

GoldenMotor.com

hipnotic

New Member
Mar 20, 2013
30
0
0
USA
Well today my banana expansion chamber cracked near the top and my acceleration and speed increased tremendously. I also remember when I first put my motor together with the stock muffler I accidentally put the washers on first, then the muffler and then the nuts. It was fast but realized it was wrong and changed it. Just for the h3!! of it I did that again today and my motor flew. If my bike had wings I would've taken off that's how fast it was. From only going 25mph before to 40mph with insane acceleration instantly without spending a single penny but with the cost of the engine being really loud!!! Anyway my question is.. Will this mess the motor up? Is it okay to do this? I switched back to normal until I know if it's okay or not.
 
Last edited:

wheelbender6

Well-Known Member
Sep 4, 2008
4,059
221
63
TX
You said the crack in the muffler is near the top. The best place to open up the exhaust is near the bottom, so that you are assured of having some back pressure and not being too loud. I would replace your cracked exhaust, at any rate.
 

hipnotic

New Member
Mar 20, 2013
30
0
0
USA
You said the crack in the muffler is near the top. The best place to open up the exhaust is near the bottom, so that you are assured of having some back pressure and not being too loud. I would replace your cracked exhaust, at any rate.
It's replaced with the stock muffler at the moment while I get the expansion chamber that cracked replaced... I don't mind the noise.. Would opening it up at the bottom some how create the same results?? Because just putting the washers on first to create a little gap between the motor and the muffler creates a lot and I mean a lot of power! But my question was.. Will this effect the motor in a negative way?
 

2door

Moderator
Staff member
Sep 15, 2008
16,302
175
63
Littleton, Colorado
one thing you don't want to do is suck cold air back onto a hot piston
Besides the damage you'll ultimately do to your engine take a moment and think how it will effect the hobby. The noise might not bother you but try to consider everyone that has to listen to that annoying sound. Install the muffler like it was designed and take the washers out from between the flange and cylinder. It might not be as fast but your engine will last longer and you won't be attracting negative attention. Do us all a favor and quiet it down.

Tom
 

bluegoatwoods

Active Member
Jul 29, 2012
1,581
6
38
Central Illinois
I'm no authority. But I think I have heard that running a 2 stroke with no exhaust, or an opened exhaust, will damage the engine. But considering how inexpensive they are, that wouldn't worry me a whole lot.

But I think 2Doors point is even more important. It wouldn't take much annoyance from the general public to cause laws and such to be passed that would make things much harder on us. It's a risk we'll have to live with as long as gasoline is fairly cheap.

It's true that this society is overrun with Harleys with straight pipes and other noise increasing mods. And I wish they'd just run stock exhausts. But trying to force them would be a really big job. Law enforcement doesn't even try.

But they won't hesitate to slap us down if they ever feel the motivation.
 

maniac57

Old, Fat, and still faster than you
Oct 8, 2011
4,484
22
0
memphis Tn
I'm no authority. But I think I have heard that running a 2 stroke with no exhaust, or an opened exhaust, will damage the engine. But considering how inexpensive they are, that wouldn't worry me a whole lot.

But I think 2Doors point is even more important. It wouldn't take much annoyance from the general public to cause laws and such to be passed that would make things much harder on us. It's a risk we'll have to live with as long as gasoline is fairly cheap.

It's true that this society is overrun with Harleys with straight pipes and other noise increasing mods. And I wish they'd just run stock exhausts. But trying to force them would be a really big job. Law enforcement doesn't even try.

But they won't hesitate to slap us down if they ever feel the motivation.
Harleys are ridden by people with money and clout to beat the law. Nowadays, more lawyers and doctors ride harleys than bikers so the cops let them alone. A motorbicyclist is nothing but an annoyance to a cop so we're MUCH more likely to get hassled for excessive noise or outlawed. We simply don't have the numbers to make lawmakers listen to our side, so we are facing increasing laws everywhere already.
Don't ride with no pipe. You are hurting ALL motorbikers position that we deserve to be left alone instead of being forced to fork out fee after fee simply to enjoy our hobby.
A few more MPH are not worth the damage to the hobby caused by the noise.
Just my opinion.
 

mew905

New Member
Sep 24, 2012
647
9
0
Moose Jaw
Harleys are ridden by people with money and clout to beat the law. Nowadays, more lawyers and doctors ride harleys than bikers so the cops let them alone. A motorbicyclist is nothing but an annoyance to a cop so we're MUCH more likely to get hassled for excessive noise or outlawed. We simply don't have the numbers to make lawmakers listen to our side, so we are facing increasing laws everywhere already.
Don't ride with no pipe. You are hurting ALL motorbikers position that we deserve to be left alone instead of being forced to fork out fee after fee simply to enjoy our hobby.
A few more MPH are not worth the damage to the hobby caused by the noise.
Just my opinion.
Yep, it may be tolerable to you, but to others, its quite annoying. Just. Like. Harleys. Difference is harleys are paying licensing and other fees, we dont (in most places). They're legal to go super fast (well... you know what I mean, obviously speeding is illegal regardless but a cop aint gunna pull em over and say "bikes are limited to 32km/hr" like they do with us some places). The lower the heat, the less bothered we'll be. Problem is some people run these on the sidewalks and do other hazardous things (even with e-bikes).

Just to put it into perspective, there's about 1 mile between my home and the main street in my town. If I ran my drilled stock exhaust, my roommate can hear me, indoors, for that whole mile. I havent been bothered about it personally, but I didn't like attracting the attention. Now I run the SBP pipe and it's actually quieter than stock, near-silent when not WOT. With a 5" straight pipe (basically the muffler cut off the header) it's so loud my ears ring after only starting it for a minute. The cold air hitting the hot piston will boost performance and cool it, but cooling metal rapidly makes it very brittle (annealing, for you aspiring blacksmiths out there), but harder. Sadly we dont want hardened pistons we want them strong. Once a piston has been annealed, it's quite easy to blow a hole straight through it, potentially destroying your motor, but definitely rendering it useless until it's replaced.
 

BarelyAWake

New Member
Jul 21, 2009
7,194
21
0
Maine
...It's true that this society is overrun with Harleys with straight pipes and other noise increasing mods. And I wish they'd just run stock exhausts. But trying to force them would be a really big job. Law enforcement doesn't even try...
Actually as it turns out you can only push them so far before something's done - our (Maine) new noise ordnance & inspection requirements thanks to those straight pipe tough guys;

A person may not operate a motor vehicle with an exhaust
system that has been modified when the result of that modification is the amplification or increase the of noise emitted by the motor above that emitted by the muffler originally installed on the vehicle.
http://maine.gov/dps/msp/licenses/documents/Vehicle Inspections/ExhaustlawChanges2010.pdf
So... thanks to the few that just couldn't control themselves we can't even lightly mod any exhaust on any vehicle legally anymore regardless of the desired effect.

Great, thanks a lot fellas :(
 

dodge dude94

New Member
Jun 8, 2012
1,017
1
0
East Texas
Actually as it turns out you can only push them so far before something's done - our (Maine) new noise ordnance & inspection requirements thanks to those straight pipe tough guys;

So... thanks to the few that just couldn't control themselves we can't even lightly mod any exhaust on any vehicle legally anymore regardless of the desired effect.

Great, thanks a lot fellas :(
Damn. That means my truck would be illegal in your state.

Oh well, that's why we have states. Don't like the laws? Change 'em or move.