Bonneville America Forums Forums Technical Forums Exhaust Exhaust leak at headers

Hey folks,

Over the last few months I've noticed that the right side of the bike is making a louder "engine sound" than the left. Since I had some valve work done, there's been an exhaust bark on the right side that was not (and is not) apparent on the left. Initially, and up until this past week since coming back from the NEast rally turning the screw out quieted it down. However, I've since noticed it getting progressively more pronounced to the point where I'm getting that "burbling" sound in decel. My limited understanding of my machine tells me that this is NOT a problem that just gets progressively worse without there being something wrong. I should not have to continually adjust my screws.

Turning the carb screw out on that side no longer solves the problem so I finally got around to getting it up on a lift to look for the obvious cracked or rotted out pipes.

Finding nothing, I turned the bike on and ran my hands quickly over the exhaust system before it heated up and found air puffing out from where the exhaust headers bolt into the cylinder head.

There are no obvious leaks or holes in the flange, the bolts seem tight, no gaps.

I'm afraid to read the words "cracked cylinder head" or something terrifyingly expensive. I'm hoping to hear, "easy...a gasket needs replacing". I'm hoping no one writes back using the words, "cracked cylinder head" or something equally terrifying and expensive.

Any thoughts?

BB

Easy fix Tad. It is a leaky copper gasket that seals the headers to the head, sorta like a donut gasket in car exhaust systems, just much thinner.
They cost $8 but you can also use much less expensive Honda header gaskets, part # in the tech vault somewhere.
Common issue, I think mine are in need of replacing as well.

Ok...so the real question is, how difficult a thing is this to do for the average "well...I can bolt stuff on" type of mechanic such as myself and what is the part number? I can't find the precise piece you're referring to on my parts disc.

BB

You need to pull your slipons, pull the headers off completely, replace two little copper discs, reinstall them all.

ok...available where? Part number? size...?

Triumph Part# 2200019-T0301 Gasket, Head to exhaust pipe
Honda part # 18291-MM5-860B

Don't forget, you need 2 gaskets!

Post deleted by Grump

For the first few thousand miles, had to periodicly re-torque those bolts. 14,000 miles, now, they don't loosen up anymore.

Post deleted by Grump

I think I should check mine... Should I put any penetrating oil on there or anything? They are pretty rusted.

I used PB Blaster on mine. I took them off thinking I could get some replacements at the local hardware store, but they didn't have a match. Sure wish I could get some replacments that wouldn't rust. Anybody know what size and thread pitch of the exhaust studs?

One thing you can do is to put another nut on top of the one that's there before you back it off. Might help to get the stud and nut off in one piece that way.

Benny,

I used Gunk's Liquid wrench. I shot all the nuts down last night and then again this morning about half an hour before I did the work. They practically spun off by hand. Which led me to consider Don's suggestion that they might just need to be torqued. I took them off anyway since I had the parts and I was curious. torquing them wouldn't have done any good. The gaskets were as flat as I can imagine them getting and they were peeling apart. They're hollow with a rollover that goes against the cylinder head. (if one can trust the original installation) They were splitting apart they were so worn.


So anyway, Don and Pat thanks for the help. I am slowly progressing to the point where someday I might actually be able to do more than stand around and nod like I know what everyone is talking about.

I did skin my knuckles...just for the record.

BB

Post deleted by Grump

Thanks guys. I just got some of that gunk stuff randomly the other day...

Don, Benny and Martin,

Don, too late. Had the work done by the time I put my post up. And...I think the Gunk stuff and the PB Blaster might be roughly equivalent. They came off so easily skinning up my knuckles again just doesn't seem like that much fun. I don't have the can in front of me but I'm pretty sure I read somewhere on it that it ALSO leaves a protective film behind. When I came out yesterday morning and looked at the studs and nuts I'd sprayed the night before, they looked like they'd come from the factory. Nice and clean, all the crud was gone.

And you're right, I probably could have got another 1000 klicks out of the gaskets just by giving the nuts an 1/8th of a crank but the right gasket was almost ready to break apart so it was good timing anyway.

Post deleted by Grump

Don,

Even so, it would have been worth the effort to just tighten them a bit just to find out. Nevertheless, like I said, I'm a struggling apprentice wrench and I had the parts and I wanted to go see.

So, now...here's another question. I resealed all the joints with high temp gasket seal and then I drilled out two quarter inch holes in the last baffle in my TOR's. (Original style) The bike sounds great...like an amp that goes to 11, just gave it that little bit more.

I had my screws out to 3 1/2. I realize this is an elementary question but since fixing those gaskets, resealing and drilling, I've changed the compression ratio. (although drilling the holes shouldn't right? Since I just gave the packing around the pipe more room to breath?) Should I be turning them back IN or out? I get no backfire on decel at all so I was wondering if since we generally turn them out to get rid of that, should I twist them in an 1/8th at a time till I get popping then back out till it stops or just leave 'em?

BB

Post deleted by Grump

Heheh...colour ME stone ignorant. But...that IS why I ask these questions after all.

Well...my feeling is if the headers aren't turning blue, (which they didn't after about 5 miles on the thruway, so they probably wont) and if I don't get any backfiring on decel, I'm happy as a gopher in soft dirt and it ain't worth my time trying to figure it out any better.

As far as how much leaking there was, I'd say a bit. Likely from where the slip-ons attach to the headers since I've never regunked them and I've leaned over and dragged them both more than a couple times which helped work them loose. There was no evidence of my original gasket seal in them when I took them off. And like I said, I could feel sigificant puffing on my hand from the cylinder. Long and short of it is I think I closed up a lot of gaps. Even before I drilled the holes, the bike sounded a lot different.

Anyway...thanks again for the help...

BB