exhaust tip----is it bad to ride with out it

yes kind of bad. What sounds sweet to you may make other people unhappy most like piece and
quiet not the noise of a little two stroke humming away. People complain about model airplanes
most all of them now have mufflers or are flown out of town.
So if you want to whizz off people and get the motorized bikes banned keep on making lots of noise.
Its best to fly under the radar, not get noticed due to noise.

probably not. there's a bit of controversy over whether or not these motors need more backpressure, but no one's proved anything, and so many people ride without the baffle, it doesn't seem to hurt it.

on the plus side, if it does hurt the motor, at least there's one less loud friggen bike on the road

I think there is a need for back pressure, I run a stock slant head and yesterday the muffler rattled loose, and there was a slight but noticeable loss in power when the sound changed, tightened it up and it ran great. Just my thoughts on the back pressure debate

Back pressure - Wikipedia, the free encyclopedia

I suppose theoretically ya might get a slight power increase in the low RPM range at the cost of power at WOT with not enough back pressure... but that would also mean it's running leaner in the higher RPM range which could be disastrous with an otherwise properly tuned 2 stroke engine.

I think given the propensity for most of these HTs to be running on the rich side, that would explain why some have reported a gain... but that's a dubious workaround, adjusting the carb properly would be a less hazardous (or annoying) solution. I also have the feeling that folks that are running w/o the end cap are likely to be running a heavy oil mix AND a rich carb setting, as well as mistaking noise for power...

*shrug* It's kinda a moot point as a proper expansion chamber is the simplest & best solution heh

louder is better

Just to let everyone know who thinks louder is better and you don't need backpressure. When I was mocking up my bike I decided to take the original muffler off that I'd put on the end of the expansion chamber and use the straight through muffler that came with the pipe. Not only was it annoyingly louder but I had LESS power and my top end just wasn't there anymore. Cut that stupid little muffler off and stuck the one back on that came with the motor and all my power and top end came right back.

So louder does not mean faster, you just think you're going faster because of the noise.

peeduh said:

louder is better

Click to expand...

...to drive the neighbors insane & to draw interest from the local enforcers - yus. Powwa? Not so much

well, I'm not an expert mechanic, but I do know less air resistance can do some good, like headers on a hotrod or 2' straight pipes on a fender less and open engine compartment. I have a 80cc Black Stallion and having the cover off the bottom didn't effect mine. Not saying that it didn't effect other people's, just not to mine or my roommates 80cc Grubee Skyhawk as well. Just made them a lot more fun to ride. My neighbors always come out to see the latest thing I've done to it. HAHA
As far as the noise goes, even though it may annoy some lame people, it does get the attention of the vehicles around you. Thus the famous motorcycle sticker "Loud pipes save lives." Just sayin
Workin for the city here, I'm stationed where the police fuel their vehicles and get them serviced so they always see me comin into work and wave or nod as I ride by. I stopped and asked one once about the law on a powered assist bike and they said as long as I'm following the same laws reg bikes follow I'm fine. I know other places are not the same.

I've also noticed that not all the muffler insides are the same, in fact pretty different. Maybe that is why some see a difference and some don't

peeduh said:

well, I'm not an expert mechanic, but I do know less air resistance can do some good, like headers on a hotrod or 2' straight pipes on a fender less and open engine compartment.

Click to expand...

Yea they sure do, on 4 cycle engines but a 2 cycle needs some back pressure to run better. Basically that's what an expansion chamber does, reflects the pressure wave BACK up the head pipe to keep the intake charge in the cylinder. Without back pressure you're losing part of your intake charge right out the exhaust every revolution which causes the engine to run lean and pistons to get burned.

The question is, Do you like riding these things? if you don't, take the muffler off completely and make all the noise you want. I had mine rattle off a half block from home and it made a **** of a racket. I got several people in that block complain. I quickly shut it off and pedaled home.

Since these things are working "under the radar" the best thing we can do is not to draw attention to ourselves. I am currently running a Sick Bike Part tuned pipe and I asked my neighbors if I was making too much noise. They didn't complain so I kept it on. When I go to school, when I get close to campus I turn the engine off and pedal it though the commons. I also lock it up right there by the bike racks and have had no complaints, although the guys at the bike-CoOp would not let me lock it in their secure area.(evil internal combustion device)

Mike

Interesting. Like I said I'm not a mechanic so learning of this is new. When i ported my exhaust I reached my finger in the cylinder to touch the top of the piston to check it and it was smooth and unpitted. I've been drivin it like this for way over a year now as well.
As for bein under the radar, you can't ride one of these and not have every kid in the neighborhood pointing and starring and getting the attention of their parents. Not to mention all the drivers on the road, some stopping us along the way to find out where they can buy one. We ride right down UT campus, even right down the "strip" and even the campus police give us the thumbs up. And if you're familiar with UT they are nit picking and very rude about ****. And they don't mess around.
My roommate rides his downtown to work at a bar,if you're familiar with Austin night life you know at night there are a couple hundred cops right there due to drama. He rides home ride by horse mounted cops as well and they give the thumbs up and a smile. The other night he was riding home down a major road and a cop car slowed next to him for a while and they gave him a nod and speed off. Maybe cops see it differently here since it's an old hippy town and they promote things like these.

Ok, so I've been doin some looking into the running without the cap thing. I talked to a guy who sells motorcycle parts and knows a bout 2stroke motors. He said esactly what you guys were saying about the needed back pressure and that I'm losing a lot of power.
So I was talking to him about an expansion chamber i read on here made out of a glade can and asked him if I would need to gut the muffler to make it work right. He stopped and looked at me and said "Gut it??" He was thinking that the muffler was just open without the cap, and after I told him about the the pipe extending to the bottom with holes in it, the flange an inch up from it closing the muffler off, and something else inside it that I can't see and then what appears to be a rolled up piece of cardboard that's about an inch wide that is placed up to the beginning of the pipe where it leaves the small pipe and enters to the bigger pipe. He then said "WHOA WHOA WHOA, that's WAAAAAAYYYYY plenty of back pressure! It may even be overkill, man!" This guy has been doing this stuff since before I was probably born-36yrs.
And like I said my muffler is different than my roommates, his doesn't have the internal parts like mine, so maybe he is losing some?
Either way, louder is definitely the best. Just sayin

First off - just guttin' the kit pipe and stickin' a air freshener can on the end does not a tuned pipe make. Nor would a kit pipe w/o any internals or an end cap be accurately called a muffler.

I would think that when you were talking to the guy he didn't think "the muffler was just open without the cap" as that's not a system at all - that's just broken. He was prolly thinkin' that like most quality two strokes it had a stock (perhaps primitive) tuned exhaust, much like Rotax comes equipped with (better than our kit pipes, but benefits from an upgrade to aftermarket).

I think I know where his "WHOA WHOA WHOA" came from & I'd agree - that "what appears to be a rolled up piece of cardboard" you refer too is most likely a catalytic converter, and that has no place on a two stroke if you expect any performance for long - they tend to clog w/unspent oil & carbon, and that does indeed contribute to having "WAAAAAAYYYYY" too much backpressure.

The sound (relative loudness) of an exhaust alone has very little to do with performance - just because it's loud doesn't mean it's superior & just because it's quiet doesn't mean there's a loss of power - THAT is personal preference alone and if ya like loud - so be it. Yet if you're trying to get the most performance out of yer engine by modifying/replacing your exhaust, that's a different topic entirely & there's gonna be very little you can do with a stock pipe - though I would recommend ridding yourself of a catalytic converter, even that is a matter of it clogging up & essentially being defective.

What a two-smoker needs to achieve a performance gain;




Go check out some true racing 2 strokes sometime & you'll notice Honda, Yamaha, Suzuki - heck, not even Kawasaki is sportin' hacked up air fresheners, funny 'nuff - they've all got expansion chambers, even silencers OMG

When a bike is loud, it makes imaginary horse power.
Loud pipes do not save lives, it just make people want to run you over even more.
Loud pipes say "Look at me mommy! Look at ME!"

Wow. That's a good one. Especially since no one said anything about noise equaling speed. Everyone knows that, especially one of those fast and furious guys with the performance muffler on their ford escort. Seriously.
I would like to write more, but the discussion went from fun debating to somewhere else.
On to the next

if you want just a little bit louder trimm off the pipe inside the cap and rip out the tin plates channel locks or a small vise grips will do then replace the cap i did this to my riverside/flyinghorse66 youll be verry pleased with the results you may have to run the needle clip one notch richer

peeduh said:

Wow. That's a good one. Especially since no one said anything about noise equaling speed. Everyone knows that, especially one of those fast and furious guys with the performance muffler on their ford escort. Seriously.
I would like to write more, but the discussion went from fun debating to somewhere else.
On to the next

Click to expand...

Touchy touchy....please re-read the posts, no one DID say anything about loudness = speed.

Also, you feel you have the right to express your opinion by saying "louder is better". Others, including myself have the same right to dispute that or, express our own opinion about "loudness".

Lighten up.