Horrible Howling

[a1bummer]

Last week when I was getting onto a busy highway from a side road, at about 7000-8000 rpms or so, I started hearing a horrible howling. When I shifted, it went away, but it came back and then gone again as I went through the gears. It sounds as though its coming from the exhaust. It seems to be come and go depending on the rpms and/or how much of a load I'm putting on the engine. As in, if I'm going down the highway at about 70mph, it is hardly there. But if I start up a hill and I maintain that speed, the howling gets louder. Today I took off both mufflers and went down the road to see if it still made the howl. Sure enough, it does. When it hits the right frequency, I can even hear it over the extremely loud noise coming out of the collector without the mufflers. I took some loose baffles out of the collector a couple years ago that were rattling. After that the exhaust sounded a bit "hollow" but not to loud or annoying. This howl sounds similar but 100 times louder. I left one baffle in there that looked like it was still welded in place quite securely. I can't imagine it could make that kind of noise if that baffle came loose. It sounds as though when the exhaust hits the right frequency, it begins to resonate inside the collector and get louder. After everything cools off enough, I'm gonna try to stick my head and a flashlight under the bike and try to look down the collector and see what it looks like.

 

Anybody else ever have this problem? I've never heard an engine make this kind of sound, so I'm assuming its the exhaust.

 

I have another collector her that I was gonna try, so I could go through the process of elimination, but the mounts have been broken off. Anybody have an extra laying around they might want to sell?

 

Thanks, Bill

[a1bummer]

Ok, this is what I found on further inspection. Before I pulled the collector off I tapped it a few times with the end of my large screwdriver. Something sounded like it was loose and vibrating. Then I took it off and tapped it a few times again. Same thing. But I noticed that when I held my hand on the ends of the collector and tapped it, it didn't make that sound. Upon further inspection I found two broken welds where the chrome shield was attached to the collector. I cleaned up the welds and took the collector down to the local shop to have the crack welded up for me. I'm gonna go pick it up here in about 45 minutes and put it all back together. Hopefully there won't be any more howling.

[a1bummer]

Well I got it back in and it still makes the same howl. I knew it might be long shot, but I had to try it. Stranger things have happened. I still can't figure out why it could howl like that now but never has before. Sooo... Does anyone have an extra collector they want to sell?

[Squeeze]

I'd probably suspect the front Headers too.

 

On the 1Gen Vmax these are double Wall Pipes and when the inside Pipe gets loose, it makes a terrible sound, as if Motor has a serious Problem with all Main Bearings and Con Rod Bearings. Makes your Heart stop for a Moment or two.

 

I'd never thought about the front Headers on the 1Gen Venture, but i'd suspect these are similar.

[rhncue]

I'd probably suspect the front Headers too.

 

On the 1Gen Vmax these are double Wall Pipes and when the inside Pipe gets loose, it makes a terrible sound, as if Motor has a serious Problem with all Main Bearings and Con Rod Bearings. Makes your Heart stop for a Moment or two.

 

I'd never thought about the front Headers on the 1Gen Venture, but i'd suspect these are similar.

 

You are correct, the pipes are double pipes. The pipes could be causing the problem but the lone baffle in the collector could be the cause also especially if it is being held in only one place. At the right resonance it might act like a reed in a musical saxophone or clarinet.

 

Dick

[a1bummer]

Are both front and rear header pipes double walled? I have spares of both out in the garage laying up in the rafters. I' have time to swap out the front today but won't have time to swap out the rear until Tuesday or so. Man I really hate these 12 hour night shifts.

 

Thanks for the info guys. I'll update ya on any progress.

 

Bill.

[Squeeze]

On the 1Gen Vmax, the rear Headers are single Pipes. Only the front are double Walled. I'm not sure about the 1gen VR.

[a1bummer]

At leas for now anyway. I changes out both front header pipes with no change in how it sounded. Then I got to thinking... while it was running I stuck the floor jack under the collector. I put only a little pressure on it and the noise went away. I let the jack back down and the noise came back. Then I grabbed my little big hammer and "messaged" the under side of the collector a little bit, and no more howling. It didn't take much. Now we'll see how long this little fix works. Before I did that, it sounded like hitting a cowbell. Now it sounds pretty solid when I tap on it with my smaller hammer.

 

I'm assuming that the header piped are double walled for two reasons. 1). The outer wall acts like somewhat of a heat shield? 2). So the chrome doesn't turn blue like it does on many single walled exhaust pipes?

 

Thanks for the replies guys.

 

Bill