Weber 42 DCOE 8

[jitenshakun]

A more experienced Z owner than I checked them and his conclusion was that if anything the jets might be a bit lean. I don't have them handy but I'll post them up later. 

 

[jonbill]

Are the jets stacks all the same then for 5 as for the other cylinders? I don't think the linkage can make #5 alone rich. It has to be something unique to #5. its jets, tubes, air bleed, cylinder rings, valves, throttle plate etc.

[jitenshakun]

Jets were the same. The idle screw had a sticky point and may not have been the same. Fingers crossed the reset might do it. 

I'm a bit unable to test right now as my fuel pump just died. Parts are on the way. 

[jitenshakun]

Jets are all the same.
Main jet 135
Maim air corrector 165
Emulsion F15
Access pump jet 45
Aux 55F8

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[jonbill]

and the idle jets too? much of the part throttle running is on the idles, not the mains.

[Patcon]

Another thing to consider is internal damage

If you crank the idle jets down too hard you open the idle orifice which makes it hard to adjust the carb. An O2 sensor would help but only if you can isolate it properly

[jitenshakun]

The visual inspection of the jets is that they look good. Fuel pump is fixed and I'll see how the idle adjustment and some fuel cleaner do.

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[jitenshakun]

Bit of an update. I figure the PO set up the carbs based on the picture below.

I added in a wideband and nailed down that the carbs were pig rich everywhere with a really lean acceleration.

I've leaned out idle jets, main jets, and idle mixture. The next step is to bump up acceleration, followed by narrowing the emulsion tube.

I also learned my engine is a recently rebuilt stock bottom end (l28) with a stock e88 (l24) head.



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[jitenshakun]

Here's what I've landed on for my L28/e88 with DCOE 42:

 

Choke 32mm

2nd vent 3.5

Main 135

Emulsion F7

Air 165

Idle 55F13

Pump 40

1.5" air horns

Elevation 3,500'

 

I have no hesitations across all types of acceleration conditions. My most problematic condition (slow acceleration off idle jet) is now a "spike" in AFR to 15. Previously it was to +20.

 

My cruising idle is a bit rich (11 AFR) but compared to all the +/- I did it's the best of the tradeoffs across jet combinations.

 

The single biggest change was going to the F7 emulsion tube, which didn't show up in any Z tips. It came from Des Hammill as a "will work with most applications" statement.

 

I haven't put it on a dyno, nor do I plan to. I had a car that could barely get up hills and was terrible out of corners while daily driving. I know have a car that snaps whenever I accelerate, pulls all the way at WOT, and has AFRs between 11 and 15 the whole time.

 

Pretty happy as a first time Weber tuner.

 

 

 

 

 

 

[jonbill]

I'm glad you've got it sorted.

[jitenshakun]

I'm glad you've got it sorted.

Thank you.

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