muffler/noise

Just finished the intake silencer and man, that works AWESOME!! I can't hardly hear anything from there! But now I can hear the engine in a way I never have before. There's this snapping crackling sound with each ignition in the engine. So I have a couple questions still. The first one is: Does anyone have an idea of what would be the most common cause of really really heavy fuel leakage near the carburetor after having had it off and basically after doing the job I did, because as soon as I started going, it started dripping so much it was nearly a stream behind me. The fuel lines aren't the culprit, but I don't know what is. I haven't been able to get it apart to figure it out, but I was hoping that somebody reading this might be able to at least point me in the right direction in order to save me some time when I do finally go to get at the heart of the leak? The second question is, do you think it might work to put a muffler on the muffler? What I mean is, I saw some small engine mufflers at Menard's(like home depot) that looked about the right size to add to my bike muffler, with a little tampering. So I was wondering if that's a good idea, and also what kind of sealant can be used for temps that high? In case I'm not clear, I'm going to have to seal some of the perimeter with some sort of epoxy type material or something, but don't know of a kind that withstands that kind of heat. Anybody know? (Thanks for reading through this long post BTW)
 
lokerman said:
Just finished the intake silencer and man, that works AWESOME!! I can't hardly hear anything from there! But now I can hear the engine in a way I never have before. There's this snapping crackling sound with each ignition in the engine. So I have a couple questions still. The first one is: Does anyone have an idea of what would be the most common cause of really really heavy fuel leakage near the carburetor after having had it off and basically after doing the job I did, because as soon as I started going, it started dripping so much it was nearly a stream behind me. The fuel lines aren't the culprit, but I don't know what is. I haven't been able to get it apart to figure it out, but I was hoping that somebody reading this might be able to at least point me in the right direction in order to save me some time when I do finally go to get at the heart of the leak? The second question is, do you think it might work to put a muffler on the muffler? What I mean is, I saw some small engine mufflers at Menard's(like home depot) that looked about the right size to add to my bike muffler, with a little tampering. So I was wondering if that's a good idea, and also what kind of sealant can be used for temps that high? In case I'm not clear, I'm going to have to seal some of the perimeter with some sort of epoxy type material or something, but don't know of a kind that withstands that kind of heat. Anybody know? (Thanks for reading through this long post BTW)
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Hey,
Sounds like a great job of you silencing the intake....I don't really know what it sounds like as I'm almost deaf and apparently the intake *whine* is high pitched which is exactly what I don't hear... I do hear low frequencies....my bike sounds like a weedeater on steroids......but anyways....there's some high temp silicone glue that's available at most auto parts stores....up to 700 degrees.....that might help...I dunno....but can you post some snapshots of your build ?....I'd really love to see how you improvised !


Thanks,
Saltybrnot
 
Sure I'll post some pics in a couple days. I got finished at night and had to stop, then the next couple days are swamped. but after that, I'll take some pics and put them up.
 
lokerman said:
Sure I'll post some pics in a couple days. I got finished at night and had to stop, then the next couple days are swamped. but after that, I'll take some pics and put them up.
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Excellent....I look forward to viewing the build !....thanks !

Laters,
Saltybrnot
 
you might check the float bowl o-ring....if you haven't already.....and everything else regarding the carb.....I dunno man....mebbe a faulty carb to begin with ?......each one of our builds is different.....love 'em or leave 'em !

Laters,
Saltybrnot
 
I bought one of those "poo poo pipes" once, but it wouldn't fit on my bike, the angles of the bends were all wrong, it didn't even look like it was made to go on a bike. I could have made it work with some serious modification, but I decided that if I was going to cut, bend and weld on a exhaust pipe, I might as well start from scratch. So I got some 3/4 electrical conduit and some high heat paint made for BBQ grills and went to work. I used to flange from the original exhaust pipe and the "black cat" muffler that came with my kit. I don't know that the bike is any quieter, but the loud poppy sound from the exhaust is now behind me instead of under me. It's much more comfortable, looks cool (IMO), and added just a little back pressure therefore increasing my low end power a little bit. Also it sounds a little deeper, but that could be just because the sound has moved. Anyway, here's some pics of it.brnot
 

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nicely done on the exhaust im going to go the same route this winter (that is if i dont end up selling my bike off lol)
 
Thanks! Here's a tip if you use galvanized conduit like I did. The paint won't stick to it very well, so what you do is wipe it down with vinegar and let it sit over night. This will leave a thin layer of zinc-oxide which is porous and will hold the paint. Just remember to degrease it before you do this so that the vinegar can get to the metal. Good luck. :)
 
OK here's some pics of the intake silencer job I did. I just copied the one from BarelyAwake, with a little modification. I'll point out that the black stuff that holds the white PVC piece to the carb and the blue hose to the grey box is JB Weld, the 4 minute kind. The first piece of PVC is a 60 degree, 1.5 inch(I think) elbow, and the second piece from the carb is a 90 degree, 1.5 inch street elbow. It fits inside the first piece snugly, but I have 2 tiny screws holding it in place just in case. The air filter is inside the grey box at the end. The part of that grey box that is attached to the hose is actually a lid of sorts, and is screwed on, thus allowing access to the foam filter for replacement or whatever. The intake noise has been reduced by something like I'm guessing about 95%. I really can only hear this kind of loud popping now, and the chain. But this hasn't been a perfect success. I was riding around and I think the airflow is too restricted, because at WOT it wasn't fully responding and wouldn't reach full RPM. Also, the air filter sponge in the grey box got kind of crunched up near the hole that goes to the hose, I think because it was not letting enough air through. I might end up replacing the box with a KNN or something, or maybe take the sponge out and put a KNN onto the box, not sure yet. As far as the leaks I reported earlier, that was due to gaskets, so I replaced all of them, and problem solved.
 

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lokerman said:
OK here's some pics of the intake silencer job I did. I just copied the one from BarelyAwake, with a little modification. I'll point out that the black stuff that holds the white PVC piece to the carb and the blue hose to the grey box is JB Weld, the 4 minute kind. The first piece of PVC is a 60 degree, 1.5 inch(I think) elbow, and the second piece from the carb is a 90 degree, 1.5 inch street elbow. It fits inside the first piece snugly, but I have 2 tiny screws holding it in place just in case. The air filter is inside the grey box at the end. The part of that grey box that is attached to the hose is actually a lid of sorts, and is screwed on, thus allowing access to the foam filter for replacement or whatever. The intake noise has been reduced by something like I'm guessing about 95%. I really can only hear this kind of loud popping now, and the chain. But this hasn't been a perfect success. I was riding around and I think the airflow is too restricted, because at WOT it wasn't fully responding and wouldn't reach full RPM. Also, the air filter sponge in the grey box got kind of crunched up near the hole that goes to the hose, I think because it was not letting enough air through. I might end up replacing the box with a KNN or something, or maybe take the sponge out and put a KNN onto the box, not sure yet. As far as the leaks I reported earlier, that was due to gaskets, so I replaced all of them, and problem solved.
Click to expand...

Another * snorkel * intake.....and it actually reduces intake whine ?.....I still don't understand why all y'all complain about intake noise....aren't cars....trucks...motorcycles way more loud ?. to each their collective own I guess.....good biking y'all....

Laters,
Salty.shft.
 
Salty Gator said:
Another * snorkel * intake.....and it actually reduces intake whine ?.....I still don't understand why all y'all complain about intake noise....aren't cars....trucks...motorcycles way more loud ?. to each their collective own I guess.....good biking y'all....

Laters,
Salty.shft.
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...nice...
 
Well Salty, I'm not complainin' - I fixed it lol TBH, If I could have the stealth of an electric with the range and power of a 2smoker I would :D

I dunno about lokerman, but I'm not interested in other people *****in' bout how annoying it is that I ride my bike past their house everyday. I'm really not interested in having my ears ring for an hour or two after I'm done riding.

I'm not sure about what you guys think, but a strung-out two stroke does not have that sexy hemi sound lol It's a pissed off chainsaw no matter how much you love it ;)

An interesting effect, I stopped at a yard sale last week and one of the guys there says to me "You used to ride past my house everyday, what happened?" I said " I dunno what you mean - I still do." Now - he wasn't complaining, he has a Harley with straight pipes but I think you get my meaning heh I'm not worried if you guys wanna pull the baffles outa yer mufflers or whatever, but I figure the only thing that could piss people off with these lil MBs is the incessant noise... including myself :p

lokerman - sounds like the "sponge" you used could itself be too restrictive, is it a proper air filter sponge? Did you oil it? Try the Briggs & Stratton w/o oil and see what happens, if it is running a bit too rich you could always adj. the carb to match. Also - make sure it's not squished in there, any "crushing" of the filter element reduces it's ability to let air through it. I wouldn't be at all surprised if you did need to adj. the air/fuel tho - the stock "air filter" might as well have not been there at all for all the good it did. Part of why I made mine was to get a better/more effective and weather-resistant intake.

I'm a lil worried about the PVC's weight on the carb and manifold, is it supported so its not all on the carb? I can see why you used it though as my carb was already canted out - I had no probs running the tubing. I wonder if yours is quieter though? Also - I worry about water gettin' in yours, do you ever leave it out/ride in the rain?

It's crazy how much noise comes from the intake on these things eh?

http://motorbicycling.com/f4/remote-airbox-intake-silencing-cheap-10967.html
 
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BarelyAwake: Yes the sponge is a proper air filter sponge, no I didn't oil it, but I think I may have squished it a little in getting it in there, I'm pretty sure I did. I didn't think about that being a problem; I thought if there were a restriction problem I would just feel it, but I was wrong. I'll try another piece and make sure it's not squished at all, and if that don't work maybe I'll do that B&S you suggest. The PVC is connected only to the carb, nothing else holding it, although I think the plastic box at the end rests on something back there a little bit. But it's all metal where the carb is, I wouldn't think it would be a problem, do you? After all, the whole thing(the part I added) doesn't weigh much, I'm pretty sure it's under a pound, and at most it can't be much more than a pound. As far as rain, I don't ride in the rain or leave it outside in the rain, so that shouldn't be a problem, although I would like it to be water resistant just for the sake of it. Mine may indeed be quieter, if the PVC is better at doing that than the tubing, but also because the tubing I used was thicker than shop vac hose; it's some kind of pool drain tubing I think.

As far as the adjustment on the fuel/air mixture, the engine was running great before I did this modification, so I have to ask why you say that? I don't know how to adjust the fuel/air mixture, or what would cause it to be necessary, so is it possible that even though it was OK before, it needs to be adjusted now anyway due to the modification?
 
It is possible that you've reduced airflow and made your mix richer, have you been keeping an eye on plug coloration before & after this mod?

Any obstruction in airflow will do this, mine was so negligible that I didn't need to adjust anything. Yet if you pull the plug and it's darker than normal you may need to move the clip on the carb's needle up one slot.

I would however support the PVC structure, prolonged use and vibration will surely cause you problems. Picture a 1lb hammer rapping away at yer carb lol and the leverage of the structure - if you grabbed it at the far end and gave it a wiggle. I try to build my bike and it's mods to withstand all sorts of misuse - like the gaggle of kids at the store that love to poke at my bike while I'm indoors, or like my buddy crashing it at 30mph o_O

One little thing - do you have a speedometer? It's a long shot, but when I did this mod to mine I thought I was going slower - but when I went home and got my GPS I found that I wasn't, it was just quieter.

I bet that it IS a lil restricted though, particularly if you squished the filter sponge. No big deal, we can get back to the fuel/air settings if that's the case ;) Just remember that running a lil rich is annoying but safe, whereas a lil lean it may harm the motor.

I like the pool drain tubing - heavier walls and custom color no less lol, but was it the wrong inner diameter to go over the carb like this?
IMG_0938s.jpg
 
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BarelyAwake: I haven't checked the plug at all. I'll do that today. The airflow was definitely reduced, so I guess that would make it richer, just didn't think about it. But first thing is to just fix the flow problem. I'm gonna get something with good flow, maybe a proper filter instead of a sponge. Also, I've looked at how other sponge setups are, and I did mine wrong so that it would have restricted airflow anyway. They are supposed to be setup so that the hose into which air flows directly after the sponge is set back a little so that it's sucking on a larger surface area than just its own diameter, but mine wasn't like that. So for example, whatever the hose is connected to should widen to several times the area of the cross section of the hose to allow the surface area of the sponge on the side where air is exiting the sponge to be as large as the surface area of the sponge where air is entering it, otherwise it's like a funneling action which would of course be restrictive. As for the support, you're right. I'll take care of that and rig something up.


Blakenstein: I was thinking more along the lines of turn signal fluid, what do you think?
 
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