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Main Area => General GS500 Discussion => Topic started by: dkidd2004 on December 25, 2013, 10:26:16 PM

Title: Pilot air screw on 04+
Post by: dkidd2004 on December 25, 2013, 10:26:16 PM
Hi

Bit confused as i'm rejetting from this guide

http://www.angelfire.com/mt2/mikesgs500/rejetting/ (http://www.angelfire.com/mt2/mikesgs500/rejetting/)

Problem is i have an 04+ GS

In the following picture is the pilot air screw the screw on the far right of the carb (just below the hose), or is it below that brass cap?

(http://img.photobucket.com/albums/v494/whanso1/2001-carb3MainMidPilotLocation.jpg)

Cheers
Dan
Title: Re: Pilot air screw on 04+
Post by: dinkydonuts on December 25, 2013, 11:13:48 PM
Here you go.

(http://i.imgur.com/PeyT2mL.jpg)
Title: Re: Pilot air screw on 04+
Post by: dkidd2004 on December 25, 2013, 11:45:17 PM
Thankyou!

Going from the tutorial it mentioned having to drill out a brass cap, however that tutorial seems to be using an older carb

Just wanted to make sure before i start doing things that can't be undone
Title: Re: Pilot air screw on 04+
Post by: radodrill on December 25, 2013, 11:53:17 PM
The exposed screw is indeed the idle/mixture screw you'll need to adjust ;)  You can see the round area at the center from a drill bit when the cap was removed
Title: Re: Pilot air screw on 04+
Post by: dinkydonuts on December 26, 2013, 12:19:50 AM
Quote from: dkidd2004 on December 25, 2013, 11:45:17 PM
Thankyou!

Going from the tutorial it mentioned having to drill out a brass cap, however that tutorial seems to be using an older carb

Just wanted to make sure before i start doing things that can't be undone

The EPA cap is the one that has to be drilled out. It provides additional adjustment for idle, but for the US market was deemed to be so evil that it had to come with a brass cap so it can't be tampered with.

Title: Re: Pilot air screw on 04+
Post by: dkidd2004 on December 26, 2013, 01:09:25 AM
So i still need to drill that out? the guide only makes mention of the one screw to be adjusted after a rejet, what does the second do/ when do i start adjusting that and to what level?
Title: Re: Pilot air screw on 04+
Post by: radodrill on December 26, 2013, 10:43:40 AM
My bike (US model GS500F) had that brass cap as well as a brass cap (with a 1mm hole through it) over the idle/mixture screw that's uncovered in your pic.  I only removed the cap that's already been removed from your carbs and that's the screw I've been using to adjust the idle mixture.

Note: this technically isn't a pilot air screw but rather the pilot mixture screw as it meters the A/F mix leaving the pilot circuit rather than metering the air entering the pilot circuit.
Title: Re: Pilot air screw on 04+
Post by: Suzuki Stevo on December 26, 2013, 11:38:36 AM
Your EPA Plugs are already gone...NO MORE DRILLING required on your part, here is a photo that still has the plugs in place.
The fact that you ended your post with "Cheers" makes me think you live somewhere that your bike probably never had them in the first place  :whisper:

(http://home.comcast.net/~stykers/drill.jpg)
Title: Re: Pilot air screw on 04+
Post by: radodrill on December 26, 2013, 12:31:23 PM
Quote from: Suzuki Stevo on December 26, 2013, 11:38:36 AMthat your bike probably never had them in the first place  :whisper:

Or a PO already drilled them out; looking at his mixture screw there is ~1/8" dia round area at the center as though a drill did that after drilling through the plug ;)
Title: Re: Pilot air screw on 04+
Post by: Suzuki Stevo on December 26, 2013, 01:12:55 PM
Quote from: radodrill on December 26, 2013, 12:31:23 PMOr a PO already drilled them out

Nahhhh....UK or maybe an Aussie  :dunno_black:
Title: Re: Pilot air screw on 04+
Post by: gsJack on December 26, 2013, 02:43:23 PM
Aussie.

http://gstwins.com/gsboard/index.php?topic=63824.msg758157#msg758157
Title: Re: Pilot air screw on 04+
Post by: dkidd2004 on December 26, 2013, 06:56:12 PM
Haha, Yes, i'm Aussie. Honestly never thought i'd get called out ending a post with "cheers" :)

I should have mentioned that isn't my pic, although my carbs are the exact same (even down to those screws already being exposed). It's from another user here, just thought i'd use it as it was far better than a phone camera pic that i snapped.

Thanks for the replies too! working off the already exposed screws i can happily say i have rejetted my bike, just needs a little fine tuning (she backfired on me once), although my tach isn't showing on my Koso gauge so i have some problem solving to do before finishing the mixture screws off.

Thanks again, you guys are probably getting tired of Carb questions by now.

Here is a quick snap of the bike (i'll update my build thread too)

(http://img12.imageshack.us/img12/7571/ylpj.jpg)
Title: Re: Pilot air screw on 04+
Post by: Suzuki Stevo on December 26, 2013, 07:09:55 PM
Sorry for going all "Nancy Drew" in this thread   :cheers:  <cheers:lolz
Title: Re: Pilot air screw on 04+
Post by: dkidd2004 on December 26, 2013, 07:17:16 PM
Haha, no worries  :thumb:

Thanks again for the info, saved me doing more harm than good :)
Title: Re: Pilot air screw on 04+
Post by: radodrill on December 26, 2013, 07:37:41 PM
What jetting are you going with?
Title: Re: Pilot air screw on 04+
Post by: dkidd2004 on December 26, 2013, 08:06:58 PM
Went with 147.5 mains, 20 pilots, 65 mids and one washer under the needle

Got this from Buddha, it's to go with a new exhaust and K&N lunchbox
Title: Re: Pilot air screw on 04+
Post by: radodrill on December 26, 2013, 08:42:39 PM
That's probably about right; I'm running stock exhaust and K&N drop-in and went with 20/60/142.5 1 washer.  I might be getting a Yosh pipe to go with it so then I'll probably be re-tuning the jetting.
Title: Re: Pilot air screw on 04+
Post by: dkidd2004 on December 26, 2013, 08:53:09 PM
The only issue i had with starting it after the rejet and install was stupidity on my part, i left the cables off of the plugs  :embarrassed:

After that hiccup, she has started and idled fine, haven't tuned the mix properly yet but seems to be running well.

Heading away for a weekend camping, so i'm happy she's at least started fine, no more garage time till monday now :( Hoping to be able to ride monday afternoon, still need to set up the gsxr rearsets (and the rear brake), reattatch the front brake, torque a few bolts and sort out my indicators, tail light and licence plate mounting. So close to finishing my build now, can't wait
Title: Re: Pilot air screw on 04+
Post by: radodrill on December 26, 2013, 08:58:05 PM
I had initially tried a 62.5 mid-main and found that the idle was a bit rich and was a bit jerky on the transition fro closed to slight throttle.  Adjusting the mixture didn't help much, so I tried slightly smaller pilots, which made it idle poorly.  Finally decided to go with one size smaller mid-main and that got it running perfectly.