Currently in the process of rebuilding my brother's carbs, and have a quick question which has left me puzzled.

His carbs appear to be rejetted, based on the grooves on the diagram needle with the C-Clip. 

In the haynes manual it states that the fuel mixture screw should be set to 3 turns out from the bottom on his bike, it appears to have been previously set to much further out than this, more like 5 or 6 turns out.

See the attached photos: https://imgur.com/a/yRBT3Cp

The screw is currently set to 3.5 turns out, you can see another 2/3 exposed clean threads, showing where it used to be set to.

Am I doing the right thing by setting it to 3 turns? Or should I be using a different spec now the carbs are rejetted?

The carbs were running great until the pilot jets both got clogged - I've now cleared them out but now the bike doesn't start.  Wondering if this could be the issue?

Ive heard that less than 1 turn out or more than 3 turns out and you should re-jet.

Has anyone tried these extended fuel mixture screws? I was thinking of buying them so I could tune my fuel mixture easily https://www.ebay.com/i/323817049347

These look higher quality, but will they fit the gs500? Ive heard we share the CV carb with harley gayvidson. https://www.amazon.com/CV-Performance-EZ-Just-Mixture-Carburetors/dp/B07C67LMK9/

Quote from: BikerBoy on May 28, 2019, 08:05:17 PM
Ive heard that less than 1 turn out or more than 3 turns out and you should re-jet.

Has anyone tried these extended fuel mixture screws? I was thinking of buying them so I could tune my fuel mixture easily https://www.ebay.com/i/323817049347

These look higher quality, but will they fit the gs500? Ive heard we share the CV carb with harley gayvidson. https://www.amazon.com/CV-Performance-EZ-Just-Mixture-Carburetors/dp/B07C67LMK9/

I saw the ebay ones. I've been tempted to buy them, but to be honest I don't see why I should be screwing with the air mixture so much to make it a necessary purchase. I'm doing a rejet soon and once I get everything set I probably wouldn't be touching those screws for a while. It does look convenient though.

Not sure where you heard that GSes share their carbs with HD, but that part is for "CV40" carbs, and I doubt that's compatible with either the Mikuni BST 33s on earlier models or the Suzuki own brand on newer ones.

The screws were probably that far out to compensate for the jets being plugged.  Which means the whole carb was likely similarly plugged.  3 turns is recommended starting point but you're expected to tune from there.  But you say it won't start now.  Did you clean the whole carb assembly or just the pilot jets?  Presuming you cleaned it all, you've cleaned off all the varnish that may have been keeping things sealed enough for the bike to run at all.

Read Mr72s blog (third time I've posted this today).  Replace all the crusty old leaky rubber bits and do a proper job of it the first (or second) time.  It's hard to tune your way around a bunch of hidden air leaks.

https://joshkarnes.blogspot.com/2017/09/fixing-common-gs500-carburetor-issues.html

Quote from: Kookas on May 30, 2019, 10:58:06 AM
Not sure where you heard that GSes share their carbs with HD, but that part is for "CV40" carbs, and I doubt that's compatible with either the Mikuni BST 33s on earlier models or the Suzuki own brand on newer ones.

I got a little ahead of myself, thanks. The ones from China for the gs500 are a quarter of the price anyway, just takes a bit longer for shipping. 

You won't need knurled mixture needles, you won't be adjusting it nearly that often. A little stubby 1" long flat screwdriver from Harbor Freight will get the job done.

If you have to turn the screws more than 3 turns out then you need to jet up. More than 3.5 turns and they don't really do anything anymore, the jet is essentially wide open, so there's no point adjusting them anymore.

My blog has info on how to set up the carbs. Those tiny pilot jets are easily clogged along with the orifices that feed fuel to them. On the other hand, the o-rings on the pilot needles tend to get hard and flat and won't seal fuel so this makes the needles do basically nothing since fuel gets by no matter what (and often leaks from the pilot needle screw hole). The solution to both problems is the same: replace the jet with one size bigger than stock and replace the o-rings on the pilot needles. And while you have the carbs apart, replace the float needle valves and clean the bowls, reset the float height, replace the float o-ring and float needle seat o-ring. And probably replace the intake boot o-rings too just to be sure. Again all this info is in my blog. You're way better off just reconditioning the carbs and setting them up correctly than trying to debug each and every problem one at a time.