My Idle air screws were 5 turns out..what will this do? - Kawasaki Vulcan 750 Forum : Kawasaki VN750 Forums
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post #1 of 7 (permalink) Old 07-18-2008, 11:32 PM Thread Starter
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My Idle air screws were 5 turns out..what will this do?

I went to adjust my idle air screws tonight and found that they were both out a full 5 turns. What types of things might this cause to my bike? Behaviors, smells, etc?

I adjusted them so that they are 2 1/2 turns now. And before anyone asks, they were full turns, not the quite easily misunderstood 1/2 turns. The bike still idles fine (at least it did when it was cold, I didn't heat it up and drive it).

Does it make any difference that I am a full mile above sea level here in Colorado?

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--Buba
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post #2 of 7 (permalink) Old 07-19-2008, 01:20 AM
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Check your fuel mileage since you set them back.
If I remember right, the more turns out means more air in the mix so you would be running leaner. Turning them back means you would be running richer.. I think.. unless I've got that backwards *L*

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post #3 of 7 (permalink) Old 07-19-2008, 09:11 AM
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Yes you do...In (clockwise) is leaner...out is richer.

The term "air screw" is a misnomer..they are really fuel screws, and add more fuel to the mix just like opening a tiny faucet.

I'm not sure if you can have a full 5 turns out without the screws falling out..but that is a bit much.

This adjustment really only makes a difference and idle and just off idle engine speeds.
If you live at a higher altitude, you can run the bike leaner anyway..some think it is just the opposite..

Because there is less oxygen per cubic foot, you have less air going through the carb. The size of the jets flow fuel at the same rate, so you end up running richer at higher altitudes and leaner as you near sea level.

Because most engines run towards the lean side to begin with, those that live in regions where they can run up into the mountains or down by the sea report no real problems with engine performance. (however cool moist dense air will make the engine run it's best)

You should also make sure your air filters are kept clean as this will have more impact at higher altitudes.

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post #4 of 7 (permalink) Old 07-19-2008, 07:36 PM Thread Starter
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So...from what it sounds, I was running really rich and was lucky I didn't lose my screws. They did seem really loose. The only harm that it might cause, then is that I would use more gas at idle and just off of idle. Would this also cause some of the hard start when hot after 15 min or less of being shut off? It only happens when I am filling the tank or run into a store real quick.

I have them set at 2 3/4 now and it seems smoother when idling. I also performed the marbling on the reed valves. I never knew the bike could be so quiet and smooth.

Thanks,
Buba
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post #5 of 7 (permalink) Old 07-19-2008, 08:36 PM
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Quote:
Originally Posted by bubalouie View Post
So...from what it sounds, I was running really rich and was lucky I didn't lose my screws. They did seem really loose. The only harm that it might cause, then is that I would use more gas at idle and just off of idle. Would this also cause some of the hard start when hot after 15 min or less of being shut off? It only happens when I am filling the tank or run into a store real quick.

I have them set at 2 3/4 now and it seems smoother when idling. I also performed the marbling on the reed valves. I never knew the bike could be so quiet and smooth.

Thanks,
Buba

Yup

The only harm that can come from running rich is fouled plugs, and in extreme cases washed down cylinder walls which lead to hard wear issues.. And as you mentioned, bad mileage. I've also seen extreme cases where a flooded exhaust system caught fire after a hard run.

Running lean, on the other hand can tear apart an engine. Detonation starts leading to holed pistons and burnt valves as a result. Bent rods can occur, as well as severly damaged cylinder walls.

The best way to determine your actual mixture status is by reading your sparkplugs. and if you have the equipment, by reading your EGT (exhaust gas temperature)

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post #6 of 7 (permalink) Old 07-19-2008, 10:05 PM
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Quote:
Originally Posted by bubalouie View Post
.. Would this also cause some of the hard start when hot after 15 min or less of being shut off? It only happens when I am filling the tank or run into a store real quick...

This is more than likely a electrical issue and not a fuel mixture one.

Do you have a maintance free AGM battery?

If not, that would be reason...

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post #7 of 7 (permalink) Old 07-21-2008, 12:52 PM Thread Starter
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yeah...haven't gotten a good battery yet. I plan on doing so soon.

Thanks for all of your help.

--Buba
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