Exhaust noise coming from under the bike

[willem]

So my '89 DOHC Seca has been pretty loud ever since I got it last January. So far I've done all the maintenance and everything important is working properly.

Now I've got my bike running right, I would like to address the noise issue a little. But when I went to look where exactly the noise was coming from, it seemed it came from the pipes themselves rather than the mufflers at the end. My pipers are wrapped (in glass fiber tape, the 5 euros per 50 meters stuff, PO put it on) so I can't actually see if there are any holes. But I can imagine there are, as the connecting H-pipe is also quite rusty. Perhaps even a hole in there somewhere, but it is hard to tell.

Anyways, what I am wondering is if there is any way of fixing up my exhaust, if I would actually have holes in the pipes? The mufflers seem okay, and maybe I can just stuff some steel wool into them to make the noise less. But if I have holes in the pipes, that's not gonna help.. I'm just wondering if actually taking off the exhausts and removing the wrap is gonna get me anywhere, if it can't be fixed I won't bother you know

Unfortunately, I don't own a garage, nor do I have a welder. Wouldn't know how to use it either. I wouldn't mind it being a ghetto fix, my bike is pretty rough anyways. I just feel for the neighbors a little bit now, since I take the bike to work in the morning.

thanks in advance, also from the neighbors

edit: I have the stock exhausts, forgot to mention that.. But some PO has drilled some holes in the back of the mufflers I think

 

[Lou Ranger]

... I wouldn't mind it being a ghetto fix, my bike is pretty rough anyways ...

Where is MacGyver when you need him?

Last month I "owned" a 450 Nighthawk until my friend finished buying it and took delivery. It had holes in the pipes near the join but they were underneath where you couldn't see them. There was enough exhaust escaping that it made the bike too lean and it would surge in the high rev range on acceleration.
I bought a couple of stainless steel hose clamps for each side, filled the holes with the highest temperature rating JB-Weld, put a thin piece of brass weather strip the length of the pipes' circumference against the JB-W and then thightened the works down with 2 clamps on each side. It completely sealed the leaks for nearly 2000 kms of riding so far, and it cured the lean surging. The clamps don't look THAT bad and, I imagine if you were to re-wrap the pipes again, you could hide them reasonably well.

 

[willem]

amazing, Lou. Thanks a bunch, I was hoping for a suggestion like that. If I manage to free up some time tomorrow I'll have a look where the holes are. My bike was running slightly lean as well, until I adjusted the idle mixture..

 

[willem]

there are some little holes in the exhaust at the lowest point of each pipe actually, but those are supposed to be there, right? To get rid of condensing water in the pipes?

 

[Scorpio1963]

I would unwrap the pipes at least where the crossover is.My bet is it is coming apart at the joint thats holding it together..The way yahmaha put these together isn't exactly genious.
My bike the crossover had rusted through where it was welded onto the muffler.Thats another possibility.Before I removed it entirely my fix was to get another crossover from a different kinda of bike which had expansion joints then clamps that held it together.
Dont know how long your wrap has been in a place but it has a tendacy to rust pipes in 2-3 years especialy if it keeps getting exposed to water.

 

[willem]

hmm right I was already suspecting the crossover piece. Luckily there's no wrap there, but I can't actually see any holes with the pipes still on the bike. Maybe I'll have a look tomorrow. Any tips on taking off the pipes btw? Should just bolt off right? Hope I don't get in trouble with bolts breaking off...

 

[Scorpio1963]

Wiilem theres a clamp with a bolt on it ,Inspect the copper piece of pipe that holds the 2 joints together for the crossover pipe.They have a tendacy to rust out underneith it.Go to partszilla and look up the muffler schematic it will show you what Im talking about ad give you better idea of what Im trying to explain

 

[willem]

so I'm back to the hole in the exhaust. Seems like last time I didn't check well enough, there is definitely a hole in my H-pipe. It's in the front one, near the middle. There's actually several small holes as far as I can see, since i can actually see through my exhaust.

Now, on to fixing it. Since I live in the Netherlands, I cannot get JB Weld here (at least not for less than 50 bucks or so). So I looked around for something similar, but could only find some metal-fixing epoxies that couldn't handle the temperatures like JB weld can. There is, however, this stuff specially for exhausts, it's called Gun Gum

But I've heard it's not very good. It can fix little holes, but doesn't hold for more than a few weeks with bigger (over 1 inch) holes. And since I'm guessing that the multiple small holes will turn into one big one as soon as I take my exhaust off and start taking away some of the rust, I'll need a better solution. So I'm thinking about using something like this:

This, in combination with some of the Gun Gum should do the trick, right? What do you guys think?

 

[Scorpio1963]

It's in the front one, near the middle.

So on your exhaust you have two hpipes?
Also do the hpipes connect into the muffler like on the sohc engines or do they go into the down pipes?

 

[willem]

yup, two h-pipes and they look like this:

 

[Lou Ranger]

If you do end up making a bigger hole, or if it crumbles away, you might consider talking to a plumber to see if, by chance the diameter of the ends coming off each header pipe is similar to whatever your standard pipe is over there. If so, then a section of copper or steel water pipe with 2 joiner clamps might do the trick.

 

[willem]

not a bad idea Lou

 

[Lou Ranger]

not a bad idea Lou

Ah yes, would that they spoke of me in hushed tones, saying, "MacGyver is his middle name ..."

 

[Scorpio1963]

Kinda difficult to know how to go about fixing your problem since I cant actualy see what it is.
If the pipe is that bad can you just remove the bad one and have a patch of metal welded in on each side to cover the area where the pipe connects to?
Another idea with question can you guys get muffler wrap over there across the pond?If so then you could just wrap the hpipe up covering all the leaks.

 

[willem]

Well it looks like my H-pipe is in pretty rough shape in general. I haven't taken the exhaust off yet, it has been raining non stop for the past few days and I don't have a garage. But from what I can see there are several small holes in the exhaust, all under half an inch in diameter as far as I can tell. But it looks a bit like swiss cheese down there. I can only imagine some small holes adding up to one big one as soon as I take away a bit of the flaky rusted parts. I'll be sure to take pics when I get around to fixing the exhaust.

Not sure if we can get muffler wrap, but is that gas tight? I have some kind of exhaust heatwrap on my pipes but that's definitely not going to keep any noise in..

and for the real mc gyver stuff, I have saved up some empty soda cans. Add some pipe clamps and gun gum and I think I'll be in business

 

[Lou Ranger]

If your bike sits outside in the rain, wouldn't that exhaust wrap hold onto moisture and accelerate rusting on the pipes? Even if under a tarp, there will be condensation trapped by the wrap, non?

 

[willem]

oui, very much so.. Maybe I'll remove the heatwrap while I'm at it..

 

[Scorpio1963]

Speaking of exhaust systems Im going to ditch the harley turnouts and baffles I bought for them for a later project.I found me a complete exhaust system for my bike thats selling for $20 plus my gas.Probaly will make the hour and half drive round trip this evening.

 

[willem]

So I managed to find some time to address this issue.

I went ahead and used the exhaust paste combined with two cans of tonic, along with some hose clamps to keep it steady.

Dismounting the exhaust was a little tricky, you actually have to loosen the H-pipes in order to get it off completely. I didn't bother, It seemed to be pretty well rusted stuck so I just fixed up the exhaust after letting it hang loose.

So I found some significant holes in my front H-pipe. No surprise that my exhaust was loud as hell if you see this (see pics).

The exhaust paste is terrible stuff, it's a sticky mess and it seems to want to stick to your hands rather than the exhaust. I used medicinal gloves, I can recommend those. I smeared a bunch of the stuff on, wrapped the pipe in some cut-up tonic can and held it down with zip ties (just for ease and speed). Then added a metal hose clamp, which I tightened down. Then cut off the zip ties again.

Results are in the pics. Haven't started the bike yet, but I'm guessing it'll be an improvement either way. I'll let you guys know how it pans out, but it'll have to wait till tomorrow since the stuff needs to set and harden.

btw, sorry for the poor pics, it's dark, I don't have a garage, and I have a shitty phone but you get the idea I guess.

 

[willem]

some more pics