Pop Off Pressure Help

[Gzunich]

How critical is it to get the correct pop off pressure according to the Mikuni charts. Please see what both carbs are showing on a dual 44's. The 95/80g readings are what are throwing me off, they don't seem to correlate correctly. I was missing the 95g springs but i bought the last one on the shelf. Could this be the cause? I am ordering 2 more online to validate.

Mikuni Recommendations

115g 95g 80g 65g
1.5 55 43 38 32
2.0 32 25 21 18
2.3 22 20 17 15
2.5 19 17 14 12

My actuals
115g 95g 80g 65g
1.5
2.0 18 23 22 30
2.3 13 16 15 22/24
2.5

I can't seem to lock one up perfect. Based on the Carb form i want to do the 95g with the 2.3n/s but its quite a bit off. i just rebuilt and cleaned the carb so i don't know what to do.

 

[Gzunich]

How critical is it to get the correct pop off pressure according to the Mikuni charts. Please see what both carbs are showing on a dual 44's. The 95/80g readings are what are throwing me off, they don't seem to correlate correctly. I was missing the 95g springs but i bought the last one on the shelf. Could this be the cause? I am ordering 2 more online to validate.

Mikuni Recommendations

115g 95g 80g 65g
1.5 55 43 38 32
2.0 32 25 21 18
2.3 22 20 17 15
2.5 19 17 14 12

My actuals
115g 95g 80g 65g
1.5
2.0 18 23 22 30
2.3 13 16 15 22/24
2.5

I can't seem to lock one up perfect. Based on the Carb form i want to do the 95g with the 2.3n/s but its quite a bit off. i just rebuilt and cleaned the carb so i don't know what to do.

 

[Quinc]

The springs are like a box of chocolates... You have to change adjust and cut until you get what you want. I just ordered 3 95g springs and 2 where the same and one was off by 3 psi.

http://www.x-h2o.com/index.php?threads/mikuni-spring-color-popoff-pop-off-chart.42190/

 

[smoofers]

I stopped using that Mikuni chart years ago. I use it as a rough starting point, but the only way to get the pop off you need is to measure and tweak. I've perfomed the same test as OP and got similar results.

 

[DAG]

Popoff does not need to match the chart.

Popoff needs to be even across both carbs.

Required popoff psi depends on your setup.

 

[Vumad]

How critical is it to get the correct pop off pressure according to the Mikuni charts.

Not at all critical. The chart is a reference. The results always vary. If the springs were as precise as the jets, you wouldn't need to check the popoff. You have to check it because the springs vary in tension, etc.

What is important is the numbers you get when you are done. The parts you use to get that number do not really matter.

Any N&S equal or larger than 1.5 will be big enough to flow the fuel you need. The rocker arm can be bent slightly to adjust for slight spring differences. You should avoid cutting the springs.

 

[Sparkplug]

Popoff is based on carb signal. The more signal, the higher the popoff. The lesser the signal, the lower the popoff. You should always use the smallest needle and seat you can to achieve the needed popoff. Popoff is very critical for the snap off idle throttle in my experience.

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