ok, who stole my air screws? They're missing!!

[Guest]

so I was tearing my carbs apart and I found that mine off my 82 GS850G do not have air screws... Here's a pic




why do mine not have air screws?

[doctorgonzo]

Haha... They are under that plug with the tiny hole in the midde. As a concession to US emissions they capped off the screw so the owner couldn't fiddle with it and cause it emit more pollution. drill a small hole and STOP BEFORE YOU HIT THE SCREW UNDERNEATH, then put a screw in the hole, grab it with pliers and pull it out. Voila, screw.

[doctorgonzo]

On a side note, pretty sure it's actually a "fuel screw". to the left or screw out is more fuel, to the right or screw tight is less fuel.

[mighty13d]

I know it regulates fuel, I just see everyone call it an air screw so I figured I'd just say that and have people know what i'm talking about!

I hate the stupid US bull about not letting us mess with our vehicles and everything. I'll grab a tiny screw and see what I can do since I'm doing this at my apt and don't have much for tools here.

[doctorgonzo]

That might work. You just need something to bite in that hole well enough to pull the cap out. Dynojet kits (for example) come with a drill bit and a screw to do it. Again, just be careful not to go too far and damage the real screw underneath. I think older VM carbs have two screws one for air, one for fuel, so that adds to the "fuel" and "air" confusion. Why are you trying to adjust it? Is the bike too lean or too rich on the pilot circuit?

[mighty13d]

I'm just trying to clean my carbs and that's suggested to do while cleaning them to make sure that everything gets properly cleaned.

[mighty13d]

think I should just leave them in there and not mess with them? or drill them, pull them and clean it out?

[doctorgonzo]

damn got the busy server message....

I'd leave them, and do it later with the right tools. The reason to check them is a PO fiddling with them and screwing them up. If yours are capped then you can be sure they are at the facftory setting. That setting is a tad lean, but not bad.

[Nessism]

On a side note, pretty sure it's actually a "fuel screw". to the left or screw out is more fuel, to the right or screw tight is less fuel.

According to the factory service manual it's a "Pilot Screw". The Z1 parts information calls it a "Fuel Mixture Screw".

"Fuel Screws" are on VM carbs, VM's also have "Air Screws".

The BS/CV carbs function differently thus the different terminology.

In terms of what to do, definitely pull them out. Clean the passage, which is subject to varnish, and replace the o-ring with a new one. Set the screws based on best running, not based on an emissions standard with may cause your bike to misbehave.

[MelodicMetalGod]

According to the factory service manual it's a "Pilot Screw". The Z1 parts information calls it a "Fuel Mixture Screw".

"Fuel Screws" are on VM carbs, VM's also have "Air Screws".

The BS/CV carbs function differently thus the different terminology.

Thank you! Excellent post! I looked all that up a couple years ago so that I could make sense out of the communications here. With so many terms being used so interchangeably and incorrectly, it makes understanding each other CHALLENGING to say the least. Maybe we need a terminology thread...? Hmmmmm....

[doctorgonzo]

According to the factory service manual it's a "Pilot Screw". The Z1 parts information calls it a "Fuel Mixture Screw".

"Fuel Screws" are on VM carbs, VM's also have "Air Screws".

The BS/CV carbs function differently thus the different terminology.

In terms of what to do, definitely pull them out. Clean the passage, which is subject to varnish, and replace the o-ring with a new one. Set the screws based on best running, not based on an emissions standard with may cause your bike to misbehave.

I usually refer to it as the "pilot" screw. Called it a "fuel" screw in this case just to make the point that it doesn't control air, it controls fuel. Opening it up lets in more fuel on the pilot circuit. I'd agree on pulling them, IF he wasn't gonna try and do it with whatever he can find lying around. It's doubtful they are a problem, so if it was me, I'd wait, get the right tools and do it the next time the carbs have to come off unless there is an apparent problem on the pilot circuit.

[Nessism]

I usually refer to it as the "pilot" screw. Called it a "fuel" screw in this case just to make the point that it doesn't control air, it controls fuel. Opening it up lets in more fuel on the pilot circuit. I'd agree on pulling them, IF he wasn't gonna try and do it with whatever he can find lying around. It's doubtful they are a problem, so if it was me, I'd wait, get the right tools and do it the next time the carbs have to come off unless there is an apparent problem on the pilot circuit.

Don't mean to split hairs but these details are pertinent: the pilot circuit feeds an emulsion mixture of fuel and air. Air is fed into the inner passages of the carbs via the air jet, where it mixes with the fuel feeding up through the pilot circuit. This emulsion mixture then feeds into the engine.

The pilot screws control the fuel mixture at idle and just above. They were set ultra lean from the factory for emissions reasons. The bike will run quite a bit better with the screws set to 2.5 to 3.5 turns out from lightly seated.

Hope this info helps.

[mighty13d]

Don't mean to split hairs but these details are pertinent: the pilot circuit feeds an emulsion mixture of fuel and air. Air is fed into the inner passages of the carbs via the air jet, where it mixes with the fuel feeding up through the pilot circuit. This emulsion mixture then feeds into the engine.

The pilot screws control the fuel mixture at idle and just above. They were set ultra lean from the factory for emissions reasons. The bike will run quite a bit better with the screws set to 2.5 to 3.5 turns out from lightly seated.

Hope this info helps.

Yeah that helps. I just wanted to know if I should take it out or not after wondering why that was capped v. having an screw there. Turns out it has the screw AND is capped!

Also, I have the tools to do it, I just prefer to do most things at my parent's place instead of my apt because I have access to things like a drill press instead of a hand-held drill and stuff like that. It's just easier. Also, I don't half-ass stuff if I can help it. If I did it, I'd do it right. I'd rather not have to pull these again for something that I could have done now.

[mighty13d]

ok 1 down, 3 to go!!!

[mighty13d]

ok so I got all 4 out without too much hassle. Only one of them was actually a little bit of a pain, They wouldn't pull out with a screw though, I had to use that drill bit in the pic to take them out instead. I can't believe that these were adjusted like they were. HOLY LEAN BATMAN!! the outside two carbs were turned all the way in tight, and the middle two were 1 turn out.... that's crazy lean compared to the 2.5-3.5 turns out!! lol damn emissions, always messing with how engines run!