AVS2 tuning

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Another good post above. Make sure timing and PCV valve are correct. Sounds like your on the right path.
 
Bewy said:
The clues are there....
IF the transfer slot position is correct, then idle quality should not change whether the rods are up or down. That is because there is insufficient airflow to activate the main system.
I suspect your pri t/blades are open too far at idle { big[ger] cam? }. Depending on a number of factors, low speed cruise can be off the transfer slots, NOT the main jets...which would explain why changing to smaller jets made no difference.
Another indicator that the blades are open too far is if you screw the mixture screws all the way in & the engine keeps running.
The first step in carb tuning is actually....ign. Get the correct amount of timing at idle that the engine WANTS; it will often be more than the factory amount because the factories had to be conservative. Once dialled in, check t/slot position. Also check that PCV is working. If it vibrates, vacuum is too low for it.
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Yes ... good info !
I glanced at the t-blades before installing but really didnt give it much thought after that . I can't visualize the idle and transition circuits on Eddies like I can on a holley .
 
In my opinion, you are over carbed. The 650 would be much more suited for your application.
 
Had the 650 version . Although it had good driving manners once it was tuned the top end paled in comparison to my Holley 750 VS.
I do wish the 800 AVS was a spreadbore.

The build is a 360
IMM ported EQs
9.5:1 and .029 quench
222/229 @.050 .513 lift @ 112 hyd roller
Air Gap
Dougs Headers to 2.5 exhaust
MP orange box 16 initial /32 total
 
Between the 650 down on power, and the 800 running like poop, leads me to the question, why did you switch from the Holley ?
 
Johnny Dart said:
In my opinion, you are over carbed. The 650 would be much more suited for your application.
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Johnny Dart said:
Between the 650 down on power, and the 800 running like poop, leads me to the question, why did you switch from the Holley ?
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AVS had better low end driveabilty , holly better top end power . I still have 4 Holleys . This is a learning excersize... I could have just slapped the 800 on out of fhe box and 99% would think it runs just fine but I wanted to maximize its efficiency and learn more about the details of tuning Carters
I mean if I just wanted a car to drive I would buy a new Honda Accord .

I still stand by my original comment that the perception that these carbs are easy to tune is wrong. I spent more time looking for one of the tiny sprongy clips last night than I would have rejetting a Holley ...lol
 
BTW , Primary T-blade was set correct. Just barely cracked open .
Still have a slight stumble when I slowly excellerate. I will try a stronger spring . I could see my afr spiking off idle.
 
mbaird said:
BTW , Primary T-blade was set correct. Just barely cracked open .
Still have a slight stumble when I slowly excellerate. I will try a stronger spring . I could see my afr spiking off idle.
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I believe you mentioned the idle mixture screws are set at 1-1/4 turns out? That iirc is on the leaner side. I’d richen the idle screws a 1/4 and see if that slight stumble goes away. Then try an 1/8 at a time either way to hone in on it. Ignore the gauge for now, adjust for drivability then If you get near the max range on the screws turned out go up one step lean on the needles or down on the jets. Basically try different combinations on screw settings, and adjust the other stuff step at a time if you get too close to max on the idle screws. Been there done that on a Street Demon 750 (same design) and ignored my gauge at first, focused on drivability and got it licked. Might work for you might not but don’t be set on a certain idle screw setting as being ideal. Gotta search for it
 
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With that cam & low-ish compression, you might need to enlarge the Idle Feed Restriction, which is the pinch at the bottom of the thin tube that hangs out the bottom of the pri boosters. Try 0.002" at a time. From memory, the 800 AVS has 1.75" t/bores. Pretty big. That means a small amount of throttle movement passes a lot of air.

Another thing to check if top end is lacking: check that the carb is getting WOT when you mash the pedal.
You wouldn't be the first person to be caught out with this....
 
You said your hesitation didn't begin until you leaned the primaries out enough that you were cruising at 15:1 (if I'm reading your thread correctly). I've found that most of my carbed engines don't like running at 15:1, so I tune them where they run best, and then check the air/fuel. Most of the time, they end up at 14-14.5:1. Otherwise, you could open up the idle circuit a little, as Bewy mentioned above, but running it a touch richer and keeping an eye on the plugs would probably get you there without having to get out the pin drills.
 
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