Basic tuning help for Mikuni carbs

  • hardrockminer
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Re: Basic tuning help for Mikuni carbs

05 Jun 2020 05:02
#827342
If you are running lean then why did you set the air screws 3 turns out?
I have several restored bikes along with a 2006 Goldwing with a sidecar. My wife has a 2019 Suzuki DR 650 for on and off road.

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  • daveo
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Re: Basic tuning help for Mikuni carbs

05 Jun 2020 08:16 - 05 Jun 2020 17:15
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Gorf wrote: Yeah so if the jet that comes stock is a 17.5, which direction do I need to go? To a 15 right?

I understand that a smaller number size 15 PILOT JET will decrease fuel flow, but a smaller number AIR JET will increase it.
Currently my RS34's have number 15 PILOT JETS with 0.6 AIR JETS installed, and the PILOT FUEL SCREWS are turned out 1/8 - 1/4 from lightly seated. With 15 PILOT JETS, 0.5 AIR JETS are too rich, but 0.7 are too lean.
With the RS36's, that combination would have been lean. Seems like I was playing with 17.5 and 20 plus PILOT JETS, and 0.7 to 0.9 AIR JETS when I had that set.

Mikuni info for reference:
www.exclusive-maag.ch/var/m_b/b6/b6b/151...Catalog.pdf?download
1982 KZ1100-A2

Last edit: 05 Jun 2020 17:15 by daveo.

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  • Gorf
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Re: Basic tuning help for Mikuni carbs

05 Jun 2020 11:53 - 05 Jun 2020 11:57
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hardrockminer wrote: If you are running lean then why did you set the air screws 3 turns out?
Following the AFR meter. I screwed all the pilot screws in as far as they would go for a starting point and took them out 1/2 turn. That gave me an idle AFR of about 22:1. Continuing to screw them out brought the AFR down until it was sitting at around 14.7:1. Which is the stoichometric ideal. But, like I said, that was 3 - 3.5 turns out. So I guess I am going to order some 20's and maybe the next step and see what happens.
Last edit: 05 Jun 2020 11:57 by Gorf.

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