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Discussion Starter · #1 ·
May I get the AF screw setting and float height for a 722a carb. Bike ran last fall but I can't get it to start now with new gas and plugs so I am going to pull the carbs clean them, benchsync and start from there but I can't find my notes on these two settings.

Also if the float was wrong and it was letting gas out the overflow do I DEcrease the float height or INcrease it?

Ty.
 

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I have my floats set at 23.5mm and AF on mine are good at about a turn and a quarter out.

Plugs look like they’re colored good.

Hope this helps.


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Discussion Starter · #3 ·
Yes that is great, TY I will start with that. Joy of a scrambler is you get to take the pipes off for this
 

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AF screw settings are just a place to start.

With the engine at operating temp, adjust the idle speed to the specified rpm. Adjust one AF screw to achieve highest rpm. Re-set idle rpm. Adjust the opposite AF screw to achieve highest rpm.

If not already done you then need to sync the carbs and then repeat the AF adjustments.

If fuel is overflowing due to float adjustment, the floats need to be adjusted lower (further from the carb body) so the valve will close earlier.
 

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Discussion Starter · #5 ·
I will have them set at 23.5, the same AF to start and bench synced tomorrow if the weather permits. I have one carb done now. The float was closer to 25.6mm. Carb cleaned diaphram looks good, it slides without catching. Once I get time to take the pipes and other carb off I will hopefully have it running better this year. Last year it ran good but I seemed to be running rich all the time. Hopefully this helps. Airfilter also clean.
 

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Discussion Starter · #7 ·
I do remember that graphic and I had the carbs both set at 26mm but I had intermitent issues all summer where one carb or the other would piss gas out the over flow. Perhaps going to 23.5 will be something to try. Thanks for the info though I got that written down now too. Wish I had a garage I would get this done tonight but when it gets dark I gota wait till tomorrow.
 

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Sound like a few possibilities, either you Float Needle Valve and Seat are bad or Float is leaking.

If the Float are set correctly they will not overflow.

One thing to watch out for when setting the float is holding the carb at the CORRECT ANGLE per the FSM
The Needle Shut Off Valve has a TINY SPRING LOADED TIP.
That is why you hold the Carb at an approx. 46 Deg. Angle NOT totally upside down, as it will compress the tip.

It is NOT to be compressed when setting the height.
If you do it will be way out of whack.
 

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Discussion Starter · #9 ·
I cleaned out the carb that was overflowing. Didn't see anything stuck in the needle area. When I set the height, I place the air intake side level on the table and let them hang down. Then using a caliper set at the height I want I measure the high point to the lib of the bowl and adjust the tab until it is juuuuuuuust before it touches the needle. I then check the other side for the same. Hopefully that works.
 

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Discussion Starter · #10 ·
Ok so which bowl has more fuel and will be richer? With the float set at 23mm or 26mm?
 

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Discussion Starter · #11 ·
Ok so I think it is the higher the height the less gas in the bowl.
1. Checked the needle it looked good but i replaced it.
2. Tested the floats in a jar, no leaks. Set them at 26mm 45 degree method tested both sides.
3. Tested the bowl, no leaks.

Next step as weather allows is to do a gravity feed test with them off the bike to check the bowl gasket for leaks and for overflow leaks. Hopefully I will do that today.
 

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Yes - you are correct.
The Measurement and fuel level in the bowl have an inverse relationship.

The great the Float Measurement the lower the fuel level and Vice Versa.
 

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Discussion Starter · #13 ·
Well on the good side the carb is not leaking now but I still can't get the bike to start up.

Fully charged battery, new gas new plugs and it turns over with the electric and kick but it won't seem to catch. Tried every position on the choke. Frustrting.
 

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It is at this point that I resort to starting fluid. I know, I know, that crap will ruin your engine.
Never happened to me, saves the battery and may/can tell you what the problem is.
 

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Discussion Starter · #15 ·
Has spark, compression getting gas. Did the cam chain valves and timing. Fully charged battery. Bike ran great last year, now it won't start.
 

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Check the KILL Switch - It will be something simple.

Take a deep breath a play with it in the morning.
 

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I did not set my carbs at an angle when I set them. It makes perfect sense. Everything I had read never mentioned it.

I wonder if I go back and remeasure at an angle, with my current setting, what kind of reading i’d get. It would probably add a mm or half possibly.

Either way, they don’t leak and bike runs well. What are the consequences of a few mm if gas is flowing into the carbs from the tank?


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