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dual 40 dcoe massive confusion


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So I've got an lz22 on my 510. It'll run and drive with enough persuasion and feathering throttle. So I yanked the emulsion tubes and noticed something. One the cylinder closest to the front has a 135 jet on the bottom. The rest are just open ended. Ill post pics later but some insight would be awesome

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Open ended as in no main jet at the end of the emulsion tube.!!

 

As previously said main jet probably fell off the emulsion tube, screw the emulsion tube back in the unscrew again and slowly with draw the tube. Main jet should stick.

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Alright last night I pulled them apart and found the jets at the bottom. All 135's so thats good news. But while I had em apart I let all the jets and tubes sit in my carb clean bucket them hosed em down with carb cleaner and inspected my jet holes. Reinstalled and ran like a champ. Even got it to idle around 1000 but still think the ignition timing is a little wonky so ill play with that tonight. Probably also going to remove and clean all my fuel delivery components this weekend

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Doctor 510 is right, im going through this in another thread here, ill post when i got it figured.

 

11 is not bad, does it stay in the 11's all the way up wide open? Low to high? If it does, maybe drop one size and accordingly on the air corrector.

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Alrighty and what would a good air/fuel ratio be? Cuz it sits around 14.1 at idle but dips down to 11at about half throttle. Thanks again guys

I guess the old ways are dying.

 

In my opinion, the only real indication of proper air/fuel is the inspection of the spark plugs. There's something called a "plug cut" which is done by driving hard and then shutting it down at high RPM then coasting to a stop. Pull the plugs hot and inspect them with a magnifying glass. This is done mainly on racing motors, but high performance motors can be done this way too.

 

The plug cut won't work for idle and low speed cruising though but it's fairly easy to get the tune right for these conditions.

 

A/F ratio gauges are not that smart, so if you're going to rely on one for tuning, at least pull a plug once in a while and do a visual inspection.

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A/F ratio gauges are not that smart, so if you're going to rely on one for tuning, at least pull a plug once in a while and do a visual inspection.

 

To be precise you would need one for each cylinder. The A/F gauge reads all cylinders mixed together.

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Right. One for each cylinder.

 

More precision could be got from a wideband O2.

 

The most accurate readings come from EGT readings. Exhaust Gas Temp gauges aren't cheap though.

 

 

It is a wideband O2 that is on the car with the sensor mounted right after the Y pipe.

 

I think your main issues are stemming from the carbs being messed with by someone who didn't know what they were doing, ie: the guy I sold it to.

I'm happy to hear you have it back to where it was, now you can focus on making it better.

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Yea I still would like to get the gasket set for it and pull it all apart and clean it cuz its still dripping gas at idle and the fuel pressure regulator is turned all the way down. maybe it is about to go bad or somethin. But for now its running really well and even idling around 1000 which I thought would never happen with that cam haha. Can't seem to figure out how to post pics for you guys tho

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