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old_rider

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Does not stop running with mixture screw all in
07/09/15 at 15:59:29

So, my bike runs a bit rich (pipe black and now muffler) and I decided I would turn down and adjust my air/fuel screw.

Well, I got back from a long run and the bike was warmed up, got off, got my screwdriver out of my toolbox and started crankin' the screw in.

And turning, and turning, and turning (about 2 1/2 times), then it bottomed out ( I made sure not to crank it closed)... and the bike was still running!! never bogged once.

Guess I have to pull the needle out and see what the issue is?

The bike still runs great, a little back firing but runs ok.

Suggestions?

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justin_o_guy2 Serious Thumper Offline What happened? Posts: 55279 East Texas, 1/2 dallas/la.	Re: Does not stop running with mixture screw all i Reply #1 - 07/09/15 at 18:29:16 So, you're at sea level, and what jets and exhaust? White spacer ?
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Kenny G Serious Thumper Offline SuzukiSavage.com The Singles Club...LOL Posts: 1754 Robson Ranch, Denton, Texas Gender:	Re: Does not stop running with mixture screw all i Reply #2 - 07/09/15 at 18:33:10 Old Rider, I am having a similar issue and have emailed Lancer and expect to hear from him soon. I will post his answer. Kenny G
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Kenny G Serious Thumper Offline SuzukiSavage.com The Singles Club...LOL Posts: 1754 Robson Ranch, Denton, Texas Gender:	Re: Does not stop running with mixture screw all i Reply #3 - 07/09/15 at 18:33:41 Old Rider, Must have hit Post twice. Kenny G
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Dave

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Re: Does not stop running with mixture screw all i
Reply #4 - 07/09/15 at 18:40:25

Sounds like your pilot jet is too big. The pilot jet uses two holes on the engine side of the butterfly in the carb to provide the mixture at idle. One of those holes bypasses the mixture screw....the other one is controlled by the mixture screw. If you can turn the screw all the way and it keeps running, that shows you the pilot jet is flowing so much fuel that the engine gets enough through the single hole that bypasses the mixture screw.

The mixture screw should ideally be at 1.5 turns out for the best performance according to the Mikuni manual. If the screw is less than 1.5 turns from seated you need a smaller pilot jet. More than 2 turns from seated and you need a larger pilot jet.

Or if this rich mixture is new and it has only recently changed.....it sounds like the fuel level in your carb may be to high or you have dirt in the carb somewhere.

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old_rider

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Re: Does not stop running with mixture screw all i
Reply #5 - 07/09/15 at 20:33:36

I will pull the bowl and check the jets.... when I get a chance to, LOL.

Jog, I did the white spacer mod, I have 2 washers...

Thing is, I have been riding it for 2 years now and I thought I had adjusted the jet for pops and after I did the spacer mod, just never turned it in all the way.

Now i'm wondering how much damage I would do if I just turned it in and rode it..... It would be lean if anything.
I have it at 1 1/2 right now, i'll jump on it tomorrow and see what it rides like....

Like I said the only reason I was attempting to adjust it was because I know its running rich. I guess the old saying holds true... IF IT AIN'T BROKE, DON'T FIX IT..

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Gary_in_NJ

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Re: Does not stop running with mixture screw all i
Reply #6 - 07/10/15 at 04:26:09

You won't do any damage with a lean pilot circuit. First, you are only riding on the pilot circuit while at partial throttle. Secondly, you aren't making enough power at partial throttle to have high enough cylinder pressure to cause heat issues. A lean or rich pilot circuit is only an annoyance as it prevents smooth throttle transistions and a wonky idle.

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Kenny G

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Re: Does not stop running with mixture screw all i
Reply #7 - 07/10/15 at 08:36:19

Old Rider,

This is what Lancer sent me:

"When you are setting/tuning the pilot screw, are you trying to find the point where the highest rpm is attained ?
If the carb is working correctly and you have the correct pilot jet, you should be able to find a spot where the rpm is highest.
Turning the pilot screw either way from the point will DECREASE rpm.
That is how you know you have found the correct setting."

I followed Lancer's procedure; I turned the pilot screw until the RPMs were as high as I could the idle speed with the pilot screw and then adjusted the idle speed with the idle speed screw. My engine is running smoother than it had been.

Kenny G

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« Last Edit: 07/10/15 at 20:20:49 by Kenny G »

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Kris01

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Re: Does not stop running with mixture screw all i
Reply #8 - 07/10/15 at 18:14:52

Turn your idle down a few hundred RPMs. Your ears become more sensitive to speed changes this way.

Turn your pilot adjusting screw until you achieve the highest idle speed. Like Dave said, 1.5 turns out from fully seated is best.

Turn your idle back up to ~1100 RPMs so you don't starve the engine for oil.
https://www.youtube.com/watch?v=91njcw1U404

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