Quick question about tailpipe noise

[Rak8986]

Hello everyone,

I am new to the site and a new motorcycle owner. I have a 1980 xs400 special with 5600 miles that I just picked up a few weeks ago as my first bike. I've taken it for a few rides and it seems to run good. The only problem I've found, and I don't even know if it's a problem, is in my exhaust pipe on the left side of my bike sounds like it has a rattle. The best way to describe it is it sounds like a bb inside of a soda can. I was wondering if anyone has ever heard this and if it is ok or if there is a problem. I plan on having it looked over in a week or two just to make sure everything else is ok.

Thanks for any help anyone can give me.

 

[eric123]

Sometimes stuff gets inside or a piece may rust or break off and rattle around.

 

[Rak8986]

That's what I was thinking. It doesn't seem to affect the bike, it's not like it's an engine ping or knock, there's no power loss so I didn't think it was anything to worry about. Quick question, I wanted to use some seafoam on my bike, should I? The guy I bought it from said he put cheap fuel/carb cleaner through it and it ended up cleaning it out but then the junk got caught in the carb. I've heard alot of great stuff about seafoam and wanted to see what everyone else's opinion on it was.

 

[OliverB]

Yep, sounds like an internal baffle rattle. Same noise in one pipe on my '80. I just ignore it. More noticeable when the muffler is cold on my bike.

Yes, do use Seafaom but you don't have to with every tank - just periodically. Do mix it with gas in a container before pouring the gas/Seafoam mix into the tank. If folks pour a slug of cleaner into the tank w/o mixing it with gas first, what the PO described may occur. Some folks assume the cleaner will mix with the gas if they pour it into a mostly empty tank then add gas. Doesn't always work!

 

[eric123]

I run Seafoam and MMO in all of my bikes...

 

[Rak8986]

Either of you use K&N air filters on yours? Did you have to re jet them after putting them on?

 

[bentwrench]

When I went to pods, I had to rejet. You probably will too (it's an enjoyably frustrating process, but you learn everything you ever wanted to know about carbs by doing it.)

 

[Joshwuh]

I had a similar problem on both of my pipes and it turned out that the baffle that sealed the header pipes to the mufflers were gone so they were just floating over the pipes and rattling all over.

 

[xschris]

gone now.

 

[JakeC83]

I also have a rattle in my right exhaust pipe. Will you listen to this video and see if it is the same type noise.

 

[xschris]

Can't see the video. But it is most likely the baffle inside has broken a weld. When I got my 80 the same thing happened. There is no fix for it other than getting another muffler.

 

[JakeC83]

Ya the first bike I owned sounded the same as this one.

Sorry...the video should be viewable now. I will most likley ignore it snd focus on the rubber around the carbs. When bike heats up it has a tendency to die and hard to restart. The rubber is riddled with cracks

 

[BBS360]

Definitely sounds like something is loose in there.

What's up with the plumber's clamp on the vacuum hose?
Carb boots look pretty worn too. Nothing to worry about yet if the bike is running well but you might get air leaks eventually.
Might want to check spark plug condition and do a carb boot test by spraying carb cleaner or starter fluid around them while idling. A change in idle rpm while spraying indicates an air leak. Should be better instructions for both tests somewhere on here.

 

[JakeC83]

Well I haven't done anything to the bike yet. It is in exactly the same condition as when I bought it. I am having an issue with it dying on idle after a 15-20 minute ride, I am wondering if the air leak from the carb boots would do that. It doesn't seem to be an issue cold. It makes sense that it would leak more when the boots expand with heat. I don't know what one of these sound like in tip top shape lol.

As for the plumbers clamp..... it was there when I got it. I should probably take the
the tank off and examine more of the vacuum lines rubber.

On a cold start after sitting a few days should this bike fire right up full choke with a kick start?

 

[xschris]

As any old bike, a good tune up and a COMPLETE carb cleaning will make a world of difference.