Air Adjustment Screw

Kyle Bagtilay

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Hi guys! Greetings from the Philippines! =)

Can you help me, please?

I have attached an image of my old carburetor, and I was wondering if the marks I indicated are the Air Adjustment Screws. :umm:

Kyle%2BBagtilay%2BCarburetor.png


Kind regards.
 
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Correct me if I am wrong, but unscrewing them makes it run more rich, and all the way closed makes it more lean. So turning it counter clockwise would make it rich, and clockwise would be lean.

But, if anyone could help me out, I was just adjusting these screws on my '81 xs400 and I still have no luck with getting the bike to idle, even when the screws are almost all the way unscrewed. I have pod filters on with no H-Pipe from mikes xs shop, and I put in new main jets as well. It runs great if I give it maybe 10 degrees or so throttle.
 
A. They are called Pilot Mixture Screws. They control air/fuel mixture deliver when the throttle is fully closed.

I see. Thank you Dave.

Is there another screw to adjust only the air? And another screw to to adjust only the fuel?

Correct me if I am wrong, but unscrewing them makes it run more rich, and all the way closed makes it more lean. So turning it counter clockwise would make it rich, and clockwise would be lean.

But, if anyone could help me out, I was just adjusting these screws on my '81 xs400 and I still have no luck with getting the bike to idle, even when the screws are almost all the way unscrewed. I have pod filters on with no H-Pipe from mikes xs shop, and I put in new main jets as well. It runs great if I give it maybe 10 degrees or so throttle.

Hi Asadam. Yup, counterclockwise makes the mixture rich. Dave said A.

I am new to bikes so I really can't help, but there's a new trick I've learned though.

My mechanic used a fluid lighter's o-ring (regulator) to replace one of the o-rings in my carburetor, and it worked fine.

I don't know, but maybe that could help.

Kyle%2BBagtilay%2BCarburetor%2Bo-ring.JPG


My problem is....... What we did yesterday was sync / balance the carbs with water displacement.

The bike (before it was sync'ed) starts instantly with just one push of the starter button (no choke needed, even when cold). After it got sync'ed, it's hard to start.

I don't know what happened, but I can tell it is 99-100% fully sync'ed since the bike sounds way different from before. Now the exhaust music are in unison, it is just....... hard to start.

I figured maybe could it be the air/fuel mixture? I don't know. :geek:

Kyle%2BBagtilay%2BCarburetor%2BSynchronize%2Bx%2BBalance.png
 
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There is a screw on the throttle arm, near where the throttle able attaches, it is for adjusting the minimum opening of the throttle when at idle. This is used to adjust the idle speed once the engine is warmed up.

Have you tried starting the bike using the choke (more properly the cold start valve)? It should be required for cold starts or the adjustments are way too rich.
 
There is a screw on the throttle arm, near where the throttle able attaches, it is for adjusting the minimum opening of the throttle when at idle. This is used to adjust the idle speed once the engine is warmed up.

Have you tried starting the bike using the choke (more properly the cold start valve)? It should be required for cold starts or the adjustments are way too rich.

Hi Dave. We tried that, but we figured out that it was the water vapor that's being sucked into the chamber that makes it moist. We just let the bike rest for like 5-10 minutes for the water vapor to evaporate, and then the bike starts with one push again.

So glad it's okay now. Bike currently chopped for re-chroming.

Thank you so much guys. Will try to help as much as I can.

This board is awesome! :bow: :bow2:

Kind regards.

Kyle%2BSabala%2BBagtilay.jpg
 
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