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Main Area => General GS500 Discussion => Topic started by: SK Racing on August 16, 2020, 08:44:34 AM

Title: Brass pipe under carbs - what connects to it?
Post by: SK Racing on August 16, 2020, 08:44:34 AM
I've had the carbs off the bike and put description tags on all the pipe connections. But there is one small brass pipe that has me stumped. There are no more rubber pipes to connect to it. Does anyone know if anything should connect to it, and if so, what?

The bike starts easily and idles fine. I can't ride, though, because I'm busy customizing it. It's a GS500F, 2004 model.

(https://i.imgur.com/T1X48rc.jpg)
Title: Re: Brass pipe under carbs - what connects to it?
Post by: sledge on August 16, 2020, 10:22:34 AM
The part is the electrically (solenoid) operated 3 way valve, part of the emissions control system/2nd air circuit

Towards the end of its life it all became complicated, different countries where the GS5 was sold got slightly different arrangements to comply with emissions legislation.

The ones we got (UK) didn't have anything fitted onto the brass pipe you have indicated......... instead there was a vented black plastic cover over it.

Your versions may be different.........I dunno  :dunno_black:

https://www.bing.com/images/search?view=detailV2&ccid=iYZMpo%2fT&id=91DB25DA182E93563BE4866F915EC55896986322&thid=OIP.iYZMpo_Tl-8kZeaJPGTzAgHaFj&mediaurl=https%3a%2f%2fexabike.com%2fPhotos%2fIMG_136619.JPG&exph=600&expw=800&q=suzuki+18115-70g10+&simid=608029801354889754&ck=2E7EB6E85BC02326BF97E127F83793AC&selectedIndex=17&FORM=IRPRST&ajaxhist=0 (https://www.bing.com/images/search?view=detailV2&ccid=iYZMpo%2fT&id=91DB25DA182E93563BE4866F915EC55896986322&thid=OIP.iYZMpo_Tl-8kZeaJPGTzAgHaFj&mediaurl=https%3a%2f%2fexabike.com%2fPhotos%2fIMG_136619.JPG&exph=600&expw=800&q=suzuki+18115-70g10+&simid=608029801354889754&ck=2E7EB6E85BC02326BF97E127F83793AC&selectedIndex=17&FORM=IRPRST&ajaxhist=0)

A better angle.......

https://www.bing.com/images/search?view=detailV2&ccid=PzmqR0iJ&id=BE29E41C2BE718C7A207CF00F04037B908A64DBB&thid=OIP.PzmqR0iJ-HMEGqkF8wPh1gHaHa&mediaurl=https%3A%2F%2Fi.ebayimg.com%2F00%2Fs%2FMTI4MFgxMjgw%2Fz%2Fd6IAAOSwPkhd8RcO%2F%24_3.JPG&exph=800&expw=800&q=suzuki+18115-70g10+&simid=608046388511179396&ck=816F177DB08E3CC9B025BC35584F6F4A&selectedindex=18&form=IRPRST&ajaxhist=0&vt=0&sim=11 (https://www.bing.com/images/search?view=detailV2&ccid=PzmqR0iJ&id=BE29E41C2BE718C7A207CF00F04037B908A64DBB&thid=OIP.PzmqR0iJ-HMEGqkF8wPh1gHaHa&mediaurl=https%3A%2F%2Fi.ebayimg.com%2F00%2Fs%2FMTI4MFgxMjgw%2Fz%2Fd6IAAOSwPkhd8RcO%2F%24_3.JPG&exph=800&expw=800&q=suzuki+18115-70g10+&simid=608046388511179396&ck=816F177DB08E3CC9B025BC35584F6F4A&selectedindex=18&form=IRPRST&ajaxhist=0&vt=0&sim=11)
Title: Re: Brass pipe under carbs - what connects to it?
Post by: SK Racing on August 16, 2020, 12:39:41 PM
Thanks Sledge. So does that mean I can just leave the brass pipe open? AFAIK, we don't have emissions control on our models in South Africa.
Title: Re: Brass pipe under carbs - what connects to it?
Post by: sledge on August 17, 2020, 01:10:34 AM
With respect I believe there is an emission control system on your bike...........the component we are talking about is actually part of it!!

But to answer the question.....yes. I believe the pipe should be open to atmosphere and I wouldn't plug it up. The cover has a tiny pin hole in it which obviously prevents any pressure differentials building up underneath.

However the cover is obviously there for a reason, without it being in place the possibility of dirt and moisture being drawn in would be a concern

Incidentally  .....does your bike have a couple of steel pipes leading to flexible hoses fitted to the front of each cylinder directly behind the headers? If so it is fitted with the PAIR system.
Title: Re: Brass pipe under carbs - what connects to it?
Post by: SK Racing on August 17, 2020, 02:05:05 AM
Of course you're right that my bike has some form of emission control.  :wink:  Just not the kind I was thinking about.

But it doesn't have PAIR. No gadgets or pipes near the headers.

I have a small watchmaker's lathe. Maybe I'll turn a plug from Delrin (acetal) with a tiny hole at the end. It will certainly prevent insects from crawling in there. Thanks for the heads up.
Title: Re: Brass pipe under carbs - what connects to it?
Post by: greasem0nk on September 02, 2020, 07:27:04 AM
I am stumped over the brass nipple on that solenoid as well. I'm in the middle of trying to repair a semi-neglected 2006 GSF-500 for my neighbor, and also, like SK Racing, can't just hop on and test ride the bike just yet.

If any US owners of these newer generation GSFs can enlighten us, I'm sure the motorcycle gods would bestow them with endless gifts of something or other.

And Hey! I'd just like to introduce myself, since this is my first post!

My name is Jeremy. I'm a small engine mechanic in Birmingham, AL. Occasionally I take on side projects for the rare customer and this is the first time I have had the chance to work on a GS. I have owned a Kawasaki EX-500 for years, and felt very comfortable working on all parts of it. It is striking how much different these two often-compared bikes really are.

Anyway, nice to have a resource like this online, and thanks in advance for anyone who can give us a full explanation on exactly what the black solenoid actually does, and how it is supposed to be connected.

-greasem0nk
Title: Re: Brass pipe under carbs - what connects to it?
Post by: sledge on September 03, 2020, 12:57:19 PM
I cant give you what I consider to be a full and complete explanation but I can give my theory.

The GS5 engine dates back to the mid 70s and rather than come up with a new and more efficient design, Suzuki added bits and pieces to make it conform with increasingly stringent emission regulations. I have never quite worked out exactly what all that plumbing around the carbs does and I have never found an explanation on the web.

Looking at the fiches its possible to make a guess on its purpose. Depending if it is open or closed it seems it allows air or maybe petrol vapour to be drawn into the engine between the R/H carb and cylinder through a check valve (#46) or it allows a vacuum to form in a chamber and/or releases it (#74)

The wiring differs on the F and the solenoid itself is triggered by the ignition control module, so RPM, the throttle position pot and the selected gear will all influence under what running conditions it operates. The F also has a neutral switch that recognises neutral, 1st and 2nd gear and it feeds back to ICM.

The actual brass pipe we are talking about may just be a requirement or product of design

(https://images.cmsnl.com/img/partslists/suzuki-gs500f-2006-k6-usa-e03-carburetor-model-k4k5k6_big3IMG00902270_98a0.gif)

Title: Re: Brass pipe under carbs - what connects to it?
Post by: greasem0nk on September 09, 2020, 08:59:09 AM
Sounds perfectly reasonable. :)

Thank you for your thoughts on its function, and the assurance that it should probably be left open.