81 Maxim xj650 Carb Sync, Running like Crap

yes, ive been bench syncing, vacuum syning, air/fuel adjusting, over and over again, im running out of ideas, here it goes, bought the bike running on only 2 cylinders, lady said the carbs needed sync, i thought "too easy" yea right i never knew it would be such a nightmare, anyways, pulled the carbs to find the bowls gunked up from sitting 2 years and a rusty tank, kreemed kit the tank, not a single clog in the carbs, im positive because i have checked it all 3 times of assembling and disassembling, ive adjusted the floats last night, last night i continue the vacuum sync and now i finally set the throttle plates to 5 in Hg on my carb sync tool with the 4 gauges, in order to keep the bike running i have to have the air/fuel screws backed out "not full turns only 7 half turns/180degrees", and when you rev the bike the rpms climb and rest at about 4000rpms, my main questions are followed...
-POSSIBLE CAUSES?
-ON THE INTAKE BOOT/THROTTLE PLATE SIDE, IT HAS 2PORTS FOR THE AIR/FUEL MIXTURE, DOES THE TOP OF THE THROTTLE PLATE "WITH NO THROTTLE GIVEN AND AT THE REST POSITION" REST IN FRONT OF THE 2 PORTS, BETWEEN THEM, OR BEHIND THEM-BEHIND THEM MEANING THE TOP OF THE THROTTLE PLATE IS TORWARD THE CENTER OF THE CARB NOT THE ENGINE"
-ON THE AIR/FUEL MIX SCREWS, DOES 1 TURN OUT MEAN 180DEGRESS OR 360 DEGREES?
-DOES TURNING THE AIR FUEL MIX SCREWS OUT LEAN OR ENRICH FUEL>

 

I WANTED TO ADD THE WHEN YOU REV THE RPMS REST AT 4000RPMS, SLOWLY FALLS DOWN TO AROUND 1000RPMS AND THEN STALLING OUT....

 

It's starving of fuel, is the tank cap vented, fitted an in-line fuel filter ? did you set the level in the bowls using the clear tube method ?
A- 1 turn = 360*
A- PMS out (anticlockwise) = richer.

 

-VALVE CLEARANCES first.

-Carbs religiously clean, slides go "clunk" and as Wiz said above, SET THE FLOATS individually using fuel and clear tubing. This has to be done very precisely; dry-setting won't do.

Then, after a good bench sync, the final vacuum sync should be just a few tweaks away.

Unless your valves are out of spec. I saw no mention of getting the valves in spec.

From the factory books:

 

it doesn't matter what hole you use, once you make them all even to either one, the idle knob will move them evenly.
just use the one you can get the best eye on and make sure the idle knob does move them uniformly.
2 3/4 full turns out is a good place to start

 

so far thanks for the replys, but yes the floats were set and measured out at there rest position, used some old clear tube from a fish tanks to check the level they hold at, I will give the adjustment another shot tomarro, i just came in from working on it, i got the bike to idle and all now, but my idle air fuel jet is only maybee 1-1.5 turns out now you cleared that up for me, fuel tank is vented, ive got all carbs reading the same at idle but now for some reason when you rev it, carb 1,2,3 read=fall=and come back up as they should but carb 4 pegs to zero when you rev it, tried to adjust but i think my neighbors are getting pissed lol, it doesnt have any mufflers.... heres a vid of my bike when i first got the bike and cleaned the carbs... http://www.youtube.com/watch?v=NR-WUO-dDkE

 

The Rubber O-ring Seals inlaid on the Intake Manifold may be flattened-out and leaking ... ==> Under LOAD.

Tightening the Manifold Bolts presents a GREAT RISK as does attempting to Remove them to replace the O-rings or apply Sealant to the Gasket.

Remove the Carbs
Squeeze some RTV on a 3" Square of Cardboard
Rubber Gloves are nice
Take a Fingertip load of RTV and FILL-IN the Gap between the Manifold & Head
"Smooche" the Sealant into the Seam
Make Air Tight.

::: WARNING :::
::: DANGER :::

The Manifold Cap Screws are likely to be seized!
They are butter-soft mild-steel and BREAK without warning.
They ==> Twist <== as if turning-out.
Then they fracture.

::::::::::::::::

 

i havnt removed the boots since ive gotten the bike, i did the leak test using a propane torch tank and with the motor running i ran the nozzle around the boots checking for a possible air leak there and nothing on a rpm change, i got the bike to idle today but im still thinking my throttle plates are off a hair, i took the bike out for a ride for the first time in several days and ran like a scalded dog lol, but guess tomarro in the morning ill continue to try and get a perfect sync...please keep the comments coming...

 

ARE YOUR VALVE CLEARANCES IN SPEC?

IT AIN'T GONNA SYNC UNLESS THEY ARE.

Talk it to death. It isn't going to work until you do it right.

Fitz out.

 

[quote="j.raulston] but my idle air fuel jet is only maybee 1-1.5 turns out[/quote]


I'd have to think it's running incredibly lean with no mufflers and only 1 turn out on the screws.

If I were you I'd go back to square one and start all over. If your valves aren't in spec you'll never get a "perfect sync", and if it's running lean it will run "like a scalded dog" until it blows, which won't take long.

 

"seven half turns" isn't 1 - 1.5 turns (??)

Do you have the stock airbox hooked-up including filter and lid and snorkel??

Or are you tuning with the carbs "open" for convenience??

 

I've had this happen to me it was the pilot jets in the carb clean them with compressed air it should do the trick

 

Fwiw..... This thread is from 3yrs ago---