Jetting for 40 DOAC webber carbs

[Guest Ian]

Hi I have a 1976 2002 with 40 DOAC  weber carbs

The car is weekend street driven for pleasure

I am having problems with the proper air/gas mixtures and wanted to know what would be the best jet setting for this type of driving

I cant remember what is in there now and I am not a true technical guy so any suggestions /help would be well appreciated.

Thanks

Ian

[Guest_anonymous]

Please do a lot of reading. Then check back in a few weeks after posting quite a bit more information.

[Dudeland]

Firstly do yourself a favour and get an Air Fuel Ratio Gauge (AFR). It makes live infinitely more easy.  AEM sells a good one for about $165, and you get a local shop to weld in a bung. 

 

It will tell you where it is rich and lean.  I couldn't have ironed out my problems with my 32/36 without it. 

 

Regards

[Dudeland]

Here is the one I got  215 on sale

 

https://www.summitracing.com/int/parts/avm-30-4110

 

 

[Doug Riparetti]

This is the one that I'm running in my "02". I HIGHLY recommend some type of "Wide band 02 sensor". I wish I would have known about these back in 1997 when i started racing circle track with the (4)-44mm Mikuni round slide motorcycle carbs. Tuning would have been WAY easier than just trying to do spark plug readings by eye....

 

https://www.summitracing.com/search/product-line/innovate-db-digital-air-fuel-ratio-gauge-with-lc-2-kits?SortBy=Default&SortOrder=Ascending&tw=innovate db&sw=Innovate DB Digital Air%2FFuel Ratio Gauge with LC-2 Kits

 

[TobyB]

What's your timing set at?

 

t

 

[Doug Riparetti]

The initial is set at 6°, up to 3000 is set at 16°  and at the 8000 it’s at 10°,  a total of 32°.  I’m running the electromotive crank trigger ignition system 

Edited February 11, 2018 by Doug Riparetti

[LimeySteve]

Remove the main & Idle jets under the little "hat" and read the numbers on all parts and also look at what chokes are fitted inside each of the air intakes . Research will tell you what I mean  its a pair of Weber 40 DCOE 's you have fitted . look in YouTube , always some good how to's on there

[oldguy]

"I don't remember what I have in there"

 

It takes 5 minutes to look.  Pop off the hats and get in there with a flat blade.  Altitude, season, heat and timing all affect jetting.

 

You need to know

 

Accelerator pumps

Idle Jets

Mains

Airs

Emulsion tubes

Chokes

 

45 idles

125-135 mains

200 airs

with 32mm chokes is a good start for a 9.5:1 street motor with a cam

 

A set of jets will run you about $50 so it pays to know what you have