Mikuni Settings For A L24

[scott]

Recently picked up a set of 44 triples and currently rebuilding them. Was going to wait to put them on a L28 but i'm pretty keen to chuck them on my L24.

They came with

 

Main-160

Air- 240

Pilot-65

Pump-55

Choke-37mm

 

Kameari suggest

 

Main-150/170

Air- 200/220

Pilot-55/57.5

Pump-40

Chokes- 34/36

 

Anyone else run 44's on a L24 before? Do Kameari specs work as a good starting point?

[600Z]

Hi Scott,

 

Not sure if this will help you but might give you a good starting point.

 

Justin

[luvemfast]

That set up would be too large on choke and too lean.

I'd also expect it to bog down when you pump the accelerator, due to pump jets being too large and making it rich.

Looks like it's come from a pretty warm motor.

[luvemfast]

This is some info I had on my phone from when I was researching my tune.

 

44mm carbs

34mm venturis

150 fuel jets

210 air

57.5 pilots (1.5 turns out)

1.8 needle/seat

45 pump jets

 

o    Pilot Jets: 20% throttle = idle = low end power

o    Main Jets: Adds (or removes) fuel from the entire RPM range = higher number equals richer mix = top end power

o    Air Jets: Smaller the Air Jet the higher the RPM and the more fuel comes in = higher number equals the leaner mix

o    Power on Air Jets: Power on lower RPM band = 210/190 air jet

o    Power on Air Jets: Power on higher RPM band = 140/150 air jet

[WA240Z]

Hi Scott,

 

I have just recently fitted 44's to my L24. Based on my experience with my engine only I would agree with Luvemfast your carbs current choke and jetting is most likely closer suited to a larger engine capacity.

 

I have 34mm chokes in mine which offers very smooth progression.

 

My jetting is currently:

 

Main Fuel - 150

Air - 200

Pilot - 57.5

Pump Nozzle - .45

 

Under load and WOT I am still too rich, so I have just been supplied 145 and 140 main fuels along with 190 and 180 main airs as my A/F ratio currently leans slightly the higher the RPM, while being too rich. As mentioned in my build thread I will have the car on the dyno in a few weeks to tune properly at the moment I am just working to get it close. I will let you know on the weekend how these new jets go and what combination I end up with.

 

Below is a link to the Mikuni suggested base line jetting for various engines including an L24 with 44's, hope it is a help.

 

http://www.mikunipower.com/PHHCarbs/PHHcatalog29.jpg

 

Billy

[dat2kman]

Factory standard for the 44's on a 2.4 are,

[scott]

thanks for the info everyone

 

Keen to see how you go with your tuning Billy. Will be watching your thread

[WA240Z]

Spent a bit of time tuning today, finished up with 190 airs and 140 main fuel. WOT under load is pretty close to around 12.5:1 A/F ratio and around 13.5:1 at cruise. That is probably as good as I will get it myself as a base line so its off to the dyno now. Will update once I have had it tuned properly.

 

Billy.

[scott]

cheers billy. Will be order an assortment of jets etc soon

[WA240Z]

Had the car on the dyno getting professionally tuned yesterday, ended up with the following:

 

34mm chokes

Main Fuel - 140

Air - 200

Pilot - 57.5

Pump Nozzle - .45

 

Hope this helps, good luck.

 

Billy

[dat2kman]

Oh look,

So close to the chart above!

[theremm]

How much accelerator pump travel are you running? I have a very similar engine setup to you WA240Z and have followed the above jetting recommendations (albeit I only have 52.5 pilots).

As per the Mikuni service manual I adjusted the pump rod to achieve 7.5mm of travel for my 44phh carbs. I am getting a significant hesitation during acceleration when I put foot to the floor though.

[WA240Z]

Mine are set up in the bottom holes. Not sure of the travel length, too hard to messure on the engine. When I was testing on the bench though before installing them the accelerator pumps could shoot fuel 6 feet. At what rev range are you bogging down when you floor the throttle? Even mine I cant just give it full aggresive throttle at 2000rpm, I need to wait until closer to 3000rpm.

If you dont already have, I strongly suggest an air fuel ratio meter. Otherwise you are only quessing.

i now have the pilot jets back to 55 and air corrector jets down to 190. Was running too rich at 100 -110km/h. Need to remember though every engine is slightly different due to compression, cam specs, valve timing, ignition timing, spark plug temp range etc, etc, etc.

[theremm]

Anything below 3,000 gives significant stumble with foot to the floor; above that it's very crisp and pulls extremely well under full throttle. Below 3,000 is only smooth when accelerating lightly.  

Haven't got an air/fuel meter unfortunately but will look into that too then.

My accelerator pump is adjusted to 7.5mm on the bottom hole, was considering going to the middle hole which would give about 9.5mm of pump travel. Might try that in addition to the 55/57.5 pilots and report back..