Air mixture screw maximum safe turn out amount?

[Iarn]

After using the search function I couldn't find anything strictly related to this.

I've got a set "The Buddha" brand jets in my carbs, along with an aftermarket exhaust and a K&N air filter and even with the rejet it's still quite lean.

I'd like to see if I can get it to be in a range where my spark plugs won't be white and ashen by turning these air/fuel mixture screws out some more (currently standard 3 turns out), but I'm not sure how much is too much? Last thing I need is to damage my carbs.

So what are the maximum amount of turns I can turn these out without harm?

[The Buddha]

6 or so and I'd worry about it falling out.
But you may have a different issue. Not many people are over 4.
Cool.
Buddha.

[Iarn]

Thank you, much! I'll give that a go and see what happens.

If you think there is another issue, do you think you could point me towards something to look at? The jets I have are from you and are meant to go with these mods (aftermarket airbox and aftermarket exhaust), so besides the air/fuel mixture screws, I'm at a bit of a loss for possible causes.

[Big Rich]

Iarn, when were your valves done last? And check your float height with the clear tube method. Both of these can cause lean looking carbs.

[Iarn]

Valve adjustments are the one thing I don't do myself. I brought it to my mechanic <1,000 miles ago. Much sooner than that, actually. I've had them checked twice since I've owned the bike. They needed adjustment the first time and were within spec the second time. He was telling me my bike was very lean as well (which I was aware of).

Haven't measured the float height, ever, though.

Appreciate the feedback, Big Rich. 

[lucas]

OK you don't adjust your own valves, but do you check them yourself?

If not I think you should start because you should be equipped to at least evaluate the health of your engine.

[Iarn]

Checked the float height using the tube method. (from the front of the bike) The left bowl seems to be right on line with the gasket. The right hand bowl seems to be about 1mm below the gasket. Is that enough to make the bike run as lean as it is? Both my plugs are white and ashen... Do I need to adjust that one bowl, and the air mixtures screws, or is there another area I could look?

[Iarn]

All right, I checked my floats and they were a bit out of sync. One bowl was at 14.2mm (I know that's within spec) and the other was ~13.8mm. I took them out and set them to ~14.6mm so now they're within 0.10mm of each other.

I also set my air/fuel screws 4.5 turns out.

I finally feel like all the age related problems with this GS are nearly fixed, and I am anxious to have my baby being tip-top shape again. I just have to get these carbs tuned to alleviate this lean state.

How soon is it feasible that the spark plugs will show signs of improvement if this has been resolved? If it's still lean, any ideas about what else would be causing a lean state? Any early ideas would be really appreciated so I can get started on this ASAP. I'm tired of hearing that knock when I idle.

[Big Rich]

I'm wondering if it's something else causing the issue. Are you sure there's no air leaks around the carb boots or something?

I mean, if your bike is running super lean and jetting doesn't solve it, there's gotta be something else. That's why Iasked about the valves earlier. 

[Watcher]

Might sound dumb, but it's something I often have to remind myself of when setting screws.

Make sure you aren't counting half turns as full turns.  Especially when adjusting installed carbs where you'll be moving the screws with a 90º tool or even just a screw-driver bit by hand.

Could be you only had the mixture screws out 1.5 turns.


Still, I don't think the screws being off by that much would cause a severe difference.

What jets are you running?

[Iarn]

Might sound dumb, but it's something I often have to remind myself of when setting screws.

Make sure you aren't counting half turns as full turns.  Especially when adjusting installed carbs where you'll be moving the screws with a 90º tool or even just a screw-driver bit by hand.

Could be you only had the mixture screws out 1.5 turns.


Still, I don't think the screws being off by that much would cause a severe difference.

What jets are you running?

I'm running 147.5 Mains and 20 Pilots from 124 mains. I bought the set from The Buddha.

It might sound dumb, but we all don't have the best attention to detail (myself mainly) and I was having a separate issue with my carbs recently where the bike seemed fuel starved, and your little reminder helped me fix it. I adjusted the screws when I fixed the float height and half turns were in fact counted as whole turns, how embarrassing  .

Moving on, they are certainly at 4.5 turns out now. So I'll post back here in a few rides and report how the plugs are looking and if the knock has gone away.

I'm wondering if it's something else causing the issue. Are you sure there's no air leaks around the carb boots or something?

I mean, if your bike is running super lean and jetting doesn't solve it, there's gotta be something else. That's why Iasked about the valves earlier. 

We will know for certain after this latest adjustment. Until then I guess we wait 

[Iarn]

It's been a few weeks now and I've been hundreds of miles and I can safely say that everything runs peachy, now. 

She runs amazing, no more sputtering (which as mentioned above was a result of my own idiocy) and the knock has gone almost completely. I still hear it some times on hot days when I'm riding hard, but it isn't all the time any more.

The spark plugs aren't perfectly balanced in their fuel mixture indication. I'd say they are a hair's breadth towards lean, but I am perfectly okay with that.

[TheGreenWeenie]

That's the type of thing you would really never catch yourself. counting half turns like that. Really solid advice. Might i ask what upgrades you're running in the way of exhaust and air filters? cause i have now, a set of 147.5 and 150 jets. not sure it would make a huge difference if i used one or the other, but it might help knowing what other people are running.

[Iarn]

That's the type of thing you would really never catch yourself. counting half turns like that. Really solid advice. Might i ask what upgrades you're running in the way of exhaust and air filters? cause i have now, a set of 147.5 and 150 jets. not sure it would make a huge difference if i used one or the other, but it might help knowing what other people are running.

Currently using a K&N Lunchbox filter and a 9" Delkevic slip-on. The lunchbox is extra nice since it makes working under the tank a lot quicker and less of a hassle. I love the sound of my Delkevic, too.

The Buddha around here is the local carb expert; He most often recommends the 147.5 main jet for aftermarket air filter and aftermarket exhaust.

[TheGreenWeenie]

Nice. i have the same set up. or will at least. cool. i'm glad i got both sized. ill start with the 147.5 and if all goes will i won't need the 150's i guess. Thanks man.and yes, the LB setups main draw for me was the space saving it provides lol.