Author Topic: Cr tuning question  (Read 1428 times)

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co425

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Cr tuning question
« on: May 24, 2010, 11:31:55 AM »
Had a mid throttle lean bog problem and got that all worked out with the needle position. Now the only problem I seem to have is a off and on pop at idle. I am prety sure this is a lean condition. Now do I need to go to bigger main jets or can I turn in the air screw to cure that.

Offline sparty

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Re: Cr tuning question
« Reply #1 on: May 24, 2010, 11:35:09 AM »
Interesting that you wrote this.  I too have just developed a slight pop at idle, but I didn't have it in the fall.  I wonder if mine is fuel related.

Art

1972 CB750 K2 Cafe' Style




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Offline Doctor_D

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Re: Cr tuning question
« Reply #2 on: May 24, 2010, 11:38:02 AM »
Main jets have nothing to do with your idle. Start with the mixture screw.  If it's more than a few turns out, you'll need to go richer on the slow jet.
Take care,
David
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1975 CB 750F - Project page: http://forums.sohc4.net/index.php?topic=66026.msg725479#msg725479
1978 CX500
1971 Norton Commando

co425

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Re: Cr tuning question
« Reply #3 on: May 24, 2010, 11:39:00 AM »
Yep other than the pop she runs great. Starts easy too. I don't think she turns a full revolution before she fires.

co425

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Re: Cr tuning question
« Reply #4 on: May 24, 2010, 11:40:03 AM »
Will do. I haven't had to touch the mixture screw. Just fine tuning now.

In is rich out is lean correct?

Offline Doctor_D

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Re: Cr tuning question
« Reply #5 on: May 24, 2010, 01:02:06 PM »
Nope, it's exactly the opposite.  Out lets in more air, making the mixture leaner.  In lets in less making the idle mixture richer.

If you don't have it, you need this: http://www.satanicmechanic.de/download/Keihin%20CR%20Special%20Owners%20Manual.pdf

Take care,
David
___________________________________________
1975 CB 750F - Project page: http://forums.sohc4.net/index.php?topic=66026.msg725479#msg725479
1978 CX500
1971 Norton Commando

co425

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Re: Cr tuning question
« Reply #6 on: May 24, 2010, 01:08:50 PM »
I'll try a 1/4 in to richen it up a little and go from there. Thanks.