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Main Area => General GS500 Discussion => Topic started by: Raydr on March 12, 2012, 05:20:37 PM

Title: How important is the seal between exhaust and head?
Post by: Raydr on March 12, 2012, 05:20:37 PM
About four years ago I posted about a new noise that my bike was making (http://gstwins.com/gsboard/index.php?topic=39381.msg442163#msg442163). I can't believe it took this long but I think I figured it out.

Today while "unwinterizing" my bike I noticed it was leaking a little more oil than usual. After taking off the fairings and poking around, I noticed that two of the bolts that hold the exhaust to the engine are missing, and the other two are loose. Oops. A quick search shows me that others have had this problem and actually noticed a significant improvement once they fixed/tightened up these bolts.

Anyway, I've decided that instead of picking up some from Lowes I'm going to order some OEM ones (I want to be sure the ones I get are strong, plus I need to buy a few other things as well.) While looking at Bike Bandit I noticed that there is a gasket (http://www.bikebandit.com/2004-suzuki-gs500f/o/m6061#sch503311) (item 1). Here's my question:

Will I probably be fine by just replacing the bolts, or should I try to replace the gasket as well? I'm not sure how important the seal is between the engine and the exhaust pipes on this bike.
Title: Re: How important is the seal between exhaust and head?
Post by: Big Rich on March 12, 2012, 05:28:20 PM
The exhaust gaskets are very important.

I think The service manual says to replace them whenever you have the exhaust off........but I've always reuse them as long as I'm able to. Of course, I do have spare gaskets waiting "just in case".
Title: Re: How important is the seal between exhaust and head?
Post by: Raydr on March 12, 2012, 05:35:20 PM
Thanks. It's only $10 for a pair so I went ahead and ordered them as well.
Title: Re: How important is the seal between exhaust and head?
Post by: tt_four on March 12, 2012, 08:57:57 PM
My bike always made a really annoying noise, and then one day I noticed a little air was blowing out at the head, so I just tightened those bolts up a bit and the noise went away, haha. Oops, it's always the stupid things.
Title: Re: How important is the seal between exhaust and head?
Post by: craigs449 on March 13, 2012, 04:54:49 AM
An exhaust air leak usually is detected by consistent backfiring of the bike.  The hot exhaust gases mix with the cool outside air prematurely and cause backfiring.
Title: Re: How important is the seal between exhaust and head?
Post by: Raydr on March 13, 2012, 02:47:13 PM
Quote from: craigs449 on March 13, 2012, 04:54:49 AM
An exhaust air leak usually is detected by consistent backfiring of the bike.  The hot exhaust gases mix with the cool outside air prematurely and cause backfiring.

I haven't had any problems except for maybe a louder engine and reduced gas mileage.

Anyway, sadly I've run in to an issue where one of the bolts seems to be rusted and won't come off. I'm going to take it to a shop eventually but for now I've just put three new bolts on. Once I can get it to a shop I'll put new gaskets on and everything.

Thanks!
Title: Re: How important is the seal between exhaust and head?
Post by: craigs449 on March 13, 2012, 04:35:16 PM
Quote from: Raydr on March 13, 2012, 02:47:13 PM
Quote from: craigs449 on March 13, 2012, 04:54:49 AM
An exhaust air leak usually is detected by consistent backfiring of the bike.  The hot exhaust gases mix with the cool outside air prematurely and cause backfiring.

I haven't had any problems except for maybe a louder engine and reduced gas mileage.

Anyway, sadly I've run in to an issue where one of the bolts seems to be rusted and won't come off. I'm going to take it to a shop eventually but for now I've just put three new bolts on. Once I can get it to a shop I'll put new gaskets on and everything.

Thanks!

try some pb blaster on it and let it sit overnight.
Title: Re: How important is the seal between exhaust and head?
Post by: Watevaman on March 13, 2012, 05:36:43 PM
 Oh god, hopefully you don't have the problem I had.

Good luck with those bolts.
Title: Re: How important is the seal between exhaust and head?
Post by: adidasguy on March 13, 2012, 08:00:27 PM
There is a similar product Seafoam Deep Creep. Similar to PB except it is not flammable and does not stink as bad.
You can apply the stuff (either one) and let it sit. Then apply some and heat the head with a torch to expand the head and tap the bolts with a small hammer. The tapping will help break the rust. The heat will expand the head more than the bolt loosening it up.
BE PATIENT!
Sometimes things need to sit for a day or two to soak into the threads.

I wonder if a crappy battery powered impact wrench would help? While it won't free the bolt, it isn't strong enough to break or strip the bolt, and the vibrations combined with heat and PB or DeepCreep might be enough to break down the rust.
Title: Re: How important is the seal between exhaust and head?
Post by: The Buddha on March 13, 2012, 08:02:45 PM
You can double up on the gaskets too, they crush rather easily. I once had a bike that sealed up a lot better with 2 instead of 1 set.
Cool.
Buddha.
Title: Re: How important is the seal between exhaust and head?
Post by: crzydood17 on March 13, 2012, 08:51:14 PM
if you need 2 gaskets your exhaust or head is warped ever so slightly...
Title: Re: How important is the seal between exhaust and head?
Post by: Raydr on March 21, 2012, 12:53:39 PM
It made a big difference. That noise is gone, and she just purrs. She also seems to accelerate and decelerate more smoothly. Overall the bike just "feels" nicer now.

I need to spend more time poking around and noticing things. It shouldn't have taken me a few years to resolve this.

Thanks everyone.