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Main Area => General GS500 Discussion => Topic started by: Grainbelt on May 02, 2006, 10:44:25 AM

Title: Stock GS stumbles at 6k
Post by: Grainbelt on May 02, 2006, 10:44:25 AM
I searched and searched, and everybody with a stumble or flat spot at 6k RPM's had a modified GS.

Mine is bone stock, just did a carb rebuild, and it runs much better than previous with the above exception.  I'm thinking I just need to mess with the mixture screws - can I do that while the carbs are on the bike? I just put it all back together...
Title: Re: Stock GS stumbles at 6k
Post by: scratch on May 02, 2006, 12:22:05 PM
You need to remove the brass plugs over the mix screws, if they haven't already.  6k rpms is in the mid range, about where the needle affects this; I have experienced this and with nearly stock jetting (plugs pulled, mix screws out 2.5 turns, 40 pilots) I shimmed the needle 1mm and that really helped stop the hesitation.
Title: Re: Stock GS stumbles at 6k
Post by: mi_dude on May 02, 2006, 02:38:53 PM
Agreed, I shimmed the needles about 2mm and it helped the hesitation in the mid rpm range.
Title: Re: Stock GS stumbles at 6k
Post by: Grainbelt on May 02, 2006, 10:40:33 PM
Please excuse my ignorance, the carb rebuild was my first foray into the internals of a carburetor.

'shimming the needles' would change the position of the needle relative to the 'slide', and the 'slide' is the big black plastic thing the needle sits in. Sounds like I would be wanting the needle to sit 1-2mm HIGHER in the slide, which would increase the size of the opening and allow more gas thru. In order for the needles to sit higher, I need a 1 mm washer to fit UNDER the little clip.

Somebody please confirm or tell me I'm  :cookoo:

Thanks so much, just want the little pink striped bugger running well.  :cheers:
Title: Re: Stock GS stumbles at 6k
Post by: lumpoffire on May 03, 2006, 12:35:29 AM
Quote from: Grainbelt on May 02, 2006, 10:40:33 PM
'shimming the needles' would change the position of the needle relative to the 'slide', and the 'slide' is the big black plastic thing the needle sits in. Sounds like I would be wanting the needle to sit 1-2mm HIGHER in the slide, which would increase the size of the opening and allow more gas thru. In order for the needles to sit higher, I need a 1 mm washer to fit UNDER the little clip.


Yes, underneath the "E" clip (c clip?)
Title: Re: Stock GS stumbles at 6k
Post by: KYGS500E on May 03, 2006, 05:25:04 AM
yeah... you'll need a #4 washer... you can get them at lowes... just slip it between the orange o-ring that fits over the needle and the e-ring
Title: Re: Stock GS stumbles at 6k
Post by: scratch on May 03, 2006, 08:32:18 AM
Slip it between part no. 6 and 11: http://gstwins.com/gsboard/index.php?topic=15469.msg135494#msg135494