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Main Area => General GS500 Discussion => Topic started by: bucket_chemist on July 17, 2012, 10:29:08 PM

Title: Under seat exhaust
Post by: bucket_chemist on July 17, 2012, 10:29:08 PM
I've seen lots of information about aftermarket exhaust systems on this site, but I'm thinking about something different. I really like the look of an under seat exhaust since I saw ver4's thread about his new, very sexy Yamaha FZ6 http://gstwins.com/gsboard/index.php?topic=61278.0 (http://gstwins.com/gsboard/index.php?topic=61278.0)

I did a quick search for under seat exhausts here, but didn't find anything. Has anyone tried to fit one to their GS?
Title: Re: Under seat exhaust
Post by: rebel_rocket on July 18, 2012, 12:44:25 AM
It's not mine but I found A pic of one. (http://cgi.stanford.edu/~sanjayd/gs500/uploads/Upgrades/undertail.jpg)
Title: Re: Under seat exhaust
Post by: bucket_chemist on July 19, 2012, 12:45:33 AM
Hey, nice find. That's pretty much what I had in mind. A cleaner execution might be nice, but it's good to know someone else has given it a go. I'm not keen on swapping out the tail section, though. I figure I need a hugger, and I can pull out the factory undertail/underseat bit. I might need to weld in a heat shield of some sort, and a place to keep the tool kit, but I think it's do-able. Now I just need time to get at it.
Title: Re: Under seat exhaust
Post by: cbrfxr67 on July 19, 2012, 07:17:25 AM
The outside pipe to undertail is hideous in my tiny two cent opinion.  Think there is any other way to do it?

and +1 "ver4's thread about his new, very sexy Yamaha FZ6"
Title: Re: Under seat exhaust
Post by: burning1 on July 19, 2012, 09:52:57 AM
I don't think there's another way to do it. Not much clearance through the swingarm, or behind the engine.

If you pay attention, a lot of undertail exhausts are routed that way. 03+ CBR600RR and a bunch of Ducati come to mind.
Title: Re: Under seat exhaust
Post by: iclrag on July 19, 2012, 09:54:18 AM
it's probably fixable with a good paint job  :icon_question:
Title: Re: Under seat exhaust
Post by: cbrfxr67 on July 19, 2012, 11:26:30 AM
Burn,

(http://image.sportrider.com/f/8862649+w750+st0/146_03_detkzoom+2003_honda_cbr600rr+chassis_right.jpg)

'ats just a wee bit different good sir!  Guess I didn't notice, errr pay attention because it is so well done and not hanging out in the open looking hideous.
Title: Re: Under seat exhaust
Post by: bucket_chemist on July 19, 2012, 12:04:16 PM
It's all about the execution, really. And I don't think that the terrible exhaust wrap on that example is helping matters much. Since it will all have to be custom made anyway, I'd go with a stainless pipe, or ceramic coated. And you have to spend some time making it fit the lines of the bike, not just whacking it on there.
Title: Re: Under seat exhaust
Post by: dgyver on July 19, 2012, 01:48:37 PM
 Here is mine. All the build pictures are on here.

(http://img.photobucket.com/albums/v64/dgyver/92GS/th_92GS027.jpg) (http://smg.photobucket.com/albums/v64/dgyver/92GS/?action=view&current=92GS027.jpg)
Title: Re: Under seat exhaust
Post by: burning1 on July 20, 2012, 12:52:45 PM
Quote from: cbrfxr67 on July 19, 2012, 11:26:30 AM
'ats just a wee bit different good sir!  Guess I didn't notice, errr pay attention because it is so well done and not hanging out in the open looking hideous.

Execution is everything. Making a kit like that look nice is all in the details. :)
Title: Re: Under seat exhaust
Post by: dougdoberman on July 20, 2012, 08:22:19 PM
http://gstwins.com/gsboard/index.php?topic=59686.0

Can sticks out a little too far for my taste, but I think it looks pretty slick with the black pipe against the black frame.
Title: Re: Under seat exhaust
Post by: rebel_rocket on July 22, 2012, 02:20:42 AM
Quote from: dgyver on July 19, 2012, 01:48:37 PM
Here is mine. All the build pictures are on here.

(http://img.photobucket.com/albums/v64/dgyver/92GS/th_92GS027.jpg) (http://smg.photobucket.com/albums/v64/dgyver/92GS/?action=view&current=92GS027.jpg)
what kind of swing arm is that?
Title: Re: Under seat exhaust
Post by: dgyver on July 22, 2012, 06:39:26 AM
Quote from: rebel_rocket on July 22, 2012, 02:20:42 AM
what kind of swing arm is that?

It is from an RGV 250. One of the few swingarms that are narrow enough to fit.
Title: Re: Under seat exhaust
Post by: burning1 on July 23, 2012, 10:32:32 AM
RGV as dgyver said. I strongly advise against doing the swap - it's not at all trivial.
Title: Re: Under seat exhaust
Post by: SAFE-T on July 24, 2012, 11:32:16 AM
Interesting that Japanese manufacturers have abandoned underseat exhaust systems as 'inefficient' in their ongoing quest for greater performance.
Title: Re: Under seat exhaust
Post by: iclrag on July 24, 2012, 01:34:13 PM
If you are trying to saev weight, an under-seat exhaust is really not helpful at all, unless your exhaust comes out the back of the engine over the tire, but why have all the un-necessary piping? i like the look of it as well, i'm just saying from their viewpoint thats my assumption
Title: Re: Under seat exhaust
Post by: burning1 on July 24, 2012, 03:32:48 PM
Anyone who thought there was a performance benefit was a fool. For weight centralization and weight reduction, under-belly seems to be the best bet. But, sometimes the reality of engine placement requires moving the exhaust system to the conventional location.

A titanium or carbon muffler just isn't that heavy to begin with.
Title: Re: Under seat exhaust
Post by: bucket_chemist on July 25, 2012, 01:20:09 AM
I always figured it was to improve ground clearance for when you're leaned way, way over. As for the GS, I just think it could look pretty cool if done right.
Title: Re: Under seat exhaust
Post by: twinrat on July 25, 2012, 02:27:45 AM
the underseat exhaust in racing is set at a pacific angle and aids performance .It is not there for centre of gravity effect .I think it was ducati or one of the other major teams had it set wrong and were handicapped in performance before they discovered there problem ,it is for the streamling effect .The benifit must be worth it to have the extra bends in the exhaust.
Title: Re: Under seat exhaust
Post by: RossLH on July 25, 2012, 05:39:11 AM
Quote from: twinrat on July 25, 2012, 02:27:45 AM
the underseat exhaust in racing is set at a pacific angle

As opposed to an Atlantic angle?
Title: Re: Under seat exhaust
Post by: BockinBboy on July 25, 2012, 06:31:32 AM
Quote from: RossLH on July 25, 2012, 05:39:11 AM
Quote from: twinrat on July 25, 2012, 02:27:45 AM
the underseat exhaust in racing is set at a pacific angle

As opposed to an Atlantic angle?

Interesting, I read this through the first time and read the word 'specific' lol

- Bboy
Title: Re: Under seat exhaust
Post by: iclrag on July 25, 2012, 08:27:19 AM
Quote from: BockinBboy on July 25, 2012, 06:31:32 AM
Quote from: RossLH on July 25, 2012, 05:39:11 AM
Quote from: twinrat on July 25, 2012, 02:27:45 AM
the underseat exhaust in racing is set at a pacific angle

As opposed to an Atlantic angle?

Interesting, I read this through the first time and read the word 'specific' lol

- Bboy
I read pacfic at first to, but i assumed he meant specific, the typo totally makes it look lik ean ocean  :icon_twisted:
Title: Re: Under seat exhaust
Post by: burning1 on July 25, 2012, 09:59:07 AM
Quote from: bucket_chemist on July 25, 2012, 01:20:09 AM
I always figured it was to improve ground clearance for when you're leaned way, way over. As for the GS, I just think it could look pretty cool if done right.

Clearance can sometimes be an issue for side-mount exhausts, but hasn't been a problem on modern race bikes since long before the introduction of the under-tail exhaust.

Quote from: twinrat on July 25, 2012, 02:27:45 AM
the underseat exhaust in racing is set at a pacific angle and aids performance .It is not there for centre of gravity effect .I think it was ducati or one of the other major teams had it set wrong and were handicapped in performance before they discovered there problem ,it is for the streamling effect .The benifit must be worth it to have the extra bends in the exhaust.

The point of lowest pressure on a motorcycle is not directly behind the tail.

http://www.gsxr-suzuki.it/en/hayabusa/hayabusa-k8/wind_tunnel.jpg
Title: Re: Under seat exhaust
Post by: burning1 on July 25, 2012, 10:03:07 AM
Seriously... Honda dropped the under-tail exhaust on the CBR1000RR, and went to under-belly. Ducati did the same on their premier sport-bike.

It's been a style thing the whole time. Extra weight, worse mass centralization, cooked ass, and no storage space. There isn't any benefit to the under-tail exhaust, despite what the manufacturers literature says.
Title: Re: Under seat exhaust
Post by: bucket_chemist on July 25, 2012, 11:48:37 AM
Quote from: burning1 on July 25, 2012, 10:03:07 AM
Seriously... Honda dropped the under-tail exhaust on the CBR1000RR, and went to under-belly. Ducati did the same on their premier sport-bike.

It's been a style thing the whole time. Extra weight, worse mass centralization, cooked ass, and no storage space. There isn't any benefit to the under-tail exhaust, despite what the manufacturers literature says.

So...you're not a fan then? :)
Title: Re: Under seat exhaust
Post by: burning1 on July 25, 2012, 12:02:30 PM
I think it looks cool.
Title: Re: Under seat exhaust
Post by: twinrat on July 25, 2012, 11:49:23 PM
SORRY GUY'S  SPECIFIC IT WAS MEANT TO BE  ,MUST OF HAD BRAIN FADE