Been looking at this thread: Where the hell is idle mixture screw? http://gstwins.com/gsboard/index.php/topic,56855

and saw this picture showing the brass plug covering the mixture screw on the old (E-model) carbs.




Then I had a look at my GS500F (2004) carbs and saw TWO brass caps on each carb. Am I correct in guessing the mixture screw is under the top one in this picture?

Another question:

If there is a brass plug over the mixture screw, logic dictates that the factory sealed it after setting it the way it should be? Why would it be necessary to adjust the screw... ever? Surely the factory took into account things like air density at different altitudes, etc.

Quote from: SK Racing on October 29, 2020, 04:29:40 AM
Been looking at this thread: Where the hell is idle mixture screw? http://gstwins.com/gsboard/index.php/topic,56855

<snip>
Then I had a look at my GS500F (2004) carbs and saw TWO brass caps on each carb. Am I correct in guessing the mixture screw is under the top one in this picture?

Oh I think so, it's in the correct spot ... Lemee at it and we'll know for sure! 

Quote from: SK Racing on October 29, 2020, 06:05:45 AM
Another question:

If there is a brass plug over the mixture screw, logic dictates that the factory sealed it after setting it the way it should be? Why would it be necessary to adjust the screw... ever? Surely the factory took into account things like air density at different altitudes, etc.

The factory makes a compromise between driveability and tailpipe emissions. (Favoring emissions that Suzuki is responsible for several years of use). Tampering (removing the plug and adjusting the screw) puts the bike outside of emissions requirements.

Quote from: Sporty on October 29, 2020, 07:16:13 AM

The factory makes a compromise between driveability and tailpipe emissions. (Favoring emissions that Suzuki is responsible for several years of use). Tampering (removing the plug and adjusting the screw) puts the bike outside of emissions requirements.

With hopefully better driveability once adjusted. Sounds like a good idea to me. I've never been 100% happy with the way my bike idle. So I shall drill out the cap and experiment... after noting how many turns out the screw was adjusted to. Just in case.