Upsized my jets! Still running lean!

I recently Bumped my jet sizes up to 112Main, 41Pilot to try and fight a lean running condition. And heres the get! It is still running LEAN!!! Ive got my pilot air mix screws out 5ish turns out just to get the plugs to brown up at IDLE but as i take it out of the driveway and down the road plug chops from 1/8th throttle to full throttle give me a lean reading. Lean like fresh out of the box new insulators WHITE no color... What am i missing? I LOVE this bike it freaking hauls! But its not gonna do jack with melted pistons!


Ok, this is my First post, so I gotta give a little backstory....
Bought a bike back in december, dont know much about bikes but i figure what the heck im kinda handy and all...
So i am talking to the P.O. after I ride it briefly and he says something like "yea I took it over to leroy and he cant believe how nice it is, he did this he did that, ya ya"
Anyway, $700 bought my very own '82 XJ650 with 28,000mi

So far i have:
Changed the oil and filter.
Lined the tank with KBS tankliner.
New Inline fuel filter.
New plugs. (P.O. was running BP6ES plugs. AND regular unleaded)
Checked valves (all are in spec) with new cover gasket.
Checked compression (All between 115/120 Dry. 155/160 Wet)
Pulled carbs, they were pretty clean, found the emulsion tube was caked up and the drain ports got the mud wasp special. Anyway, all else was ok, but here are my carb sins/judgement calls:
Did, not break the rack/ replace throttle shaft seals(propane test has found no vac leaks)
Did not replace pilot screw washer or oring(judgment call) but I did remove and inspect/clean passage and parts.
Did not replace float valves. (Judgement)
Everything else is clean and all 4 pass the clunk test. CLUNK I love it! Thanks Rick!
Put it all back together, set floats all at 3MM. geez what a pain! the hardest part for me was getting things all level...
Got, the bike running, pilot screws way out just to get a little brown on the plugs.
SYnched(but without YICS tool)(

 

Ive got a sneaking suspicion....
Draining fuel.
Carbs are coming out!

 

Have we ruled out:

-Vacuum leak
-air filter loose
-carb piston rubber seated properly

 

stock pipes and air box ?

 

HeyGuys
Thanks for the replies:
Polock! Great to see that nose!

Bone stock brothers. Well, other than my jets...

2into4, new Air Filter in stock box. Had previously removed old fuse box which left two holes in the lid just sealed those with RTV
Have we ruled out:

-Vacuum leak
-air filter loose
-carb piston rubber seated properly

we have ruled out air filter loose and the carb piston rubber I seated with a film of silicone grease

As for vacuum leak... with the bike idleing ill poke around with an unlit propane torch to try and hear running changes but I havent yet. what im not as sure about is if i hit it already going 55 do i suddenly have vacuum leaks?

I have two theories right now: one the pilot circuit passages are not 100% clean..(how do you make sure that things clean? Its got so many turns! And what is that restriction under the pilot jet?) and the other is that the intake manifolds are leaking under load...

My carbs are out now by the way so any carb ideas let er riippp

 

if you have 5 turns on the pilots and bigger jets, can't find a vacuum leak i'd say ride it
put 2 or 3 hundred K's on it see how it feels and then pull the plugs
if you just started riding your not going to melt any pistons
watch for flat spots in the rpm's and stalling after a good run down the hi-way

 

Yea? Alright, ive got a 400 mile trip planned from northern VA to Northern NJ thru the mountains of PA down thru the Water Gap... Its gonna be fun!!!
But still trying to relax about mechanical issues

WHat would flat spots in the rpm's and stalling after a good run down the hi-way indicate? Fuel starvation?

I mean this thing is seriously running like a beast itll hold 65 with power to go. i cruise 55 at 1/8 throttle pick it up at 1/4 take off at half scream at 3/4 and superman at full on

 

i'd try shimming up the needles. the good news is that you can do this without completely removing the carbs - just pull the hats off. you might have to partially remove an airbox boot to get your finger in there to help the needle seat into the emulsion tube.

my bike was acting the same way - the only difference is the order of approach. 1st, i increased main fuel jets. 2nd, i shimmed up the needles, and 3rd i increased the pilot jets. i've noticed an improvement with each change, but i haven't colortuned yet with the larger pilot jets.

 

Skeeter,
Could you explain shimming up the needles for me? What am i using for a shim and where is it placed? I am assuming where the needle passes thru the piston but that is very thin metal to try and catch a shim on...

 

unscrew the plastic bolt that holds the needle into the piston and remove the needle. put a small washer around the needle and re-install the needle back into the piston. the washer will hold the needle up - as though your piston was partially opened - and allow more fuel out of the main jet.

 

yea, thats kinda how i figured it would go what size washer would you recommend? wait, lemme guess thats where all the fun is, playing around with various sizes...

 

well, you could call it fun if you want. i'd just try to make sure that all 4 carbs get shimmed with the same size washer. i've got 2 washers under each of my needles.

 

Eparker... Have you returned from your journey? I'm very anxious to hear what you've found out, since I'm experiencing an extremely lean issue on my bike (we have the same bike as well!)

-I am also at 5 turns out, with no sign of color on the plugs.
-Stock airbox and exhaust
-Checked for air leaks with torch and none were found at the manifolds or intake boots. Although, I haven't checked the airbox lid for leaks and had considered installing some weatherproof sealer around the lip of the lid. I should test that for leaks next.
-Running a 118 main fuel jet, installed by PO and stock pilot jet.
-I also thought my pilot circuit to be clogged so I cleaned the passages a dozen times with cleaner and compressed air, even boiled them in lemon juice prior to the cleaning. Turning the pilot jets do cause the bike's idle to change so they have to be clear. I think...

I'm certain we can find a solution to this annoyance soon but I have a nagging feeling that we're getting an extra boost of air somewhere! I considered trying shimming the needles too just for kicks.

 

Funny, I have the same bike, and it's super lean too.

I'm fairly sure I have some sort of air leaks on the boots and my shaft seals. It's the only explanation. :evil:

 

Yep, well Ive been so busy, havent been able to update. I ended up installing shims (4mm washers for .47 cents from Home depot) under the needles and putting it all back together and running it thru my trip. 400 miles thru the PA mountains, what fun. Bike ran great no problems. but something just doesnt add up.. Ive got upsized jets, shimmed needle and still plug chops look lean.. also averaging 40+ MPG.. AND I KNOW im putting more fuel in... anyway once arriving in my destination i promply parked the bike, borrowed a truck and returened to VA. MOVING sucks.. just got back to the bike last week, fired it up, ran great took a short ride no complaints. well other than the little dribble of oil i noticed from the front right fork seal. i love projects... so as for mix? i dunno, right now i cant really mess with it. when i get time, and after fork seal replacements, i may throw a second set of washers at it. also thought about replacing intake manifolds and airbox to carb boots, just cant quite see that as the problem if all 4 plugs are chopping so similarly. BUT. i know im not the onlyone on here with this problem so good luck guys, altho there is very little luck in mechanics...

 

how lean, exactly, are you? i'd say if you didn't burn it up in 400 miles, i'd say you're probly ok.

does the bike perform like it's lean? stumble from take off or flat spot in a certain RPM range?

 

ok, i'm another one with this problem, BUT, eparker our bikes require a BP7ES, not a BP6ES!!! your plug is too hot, the lower the # the hotter it burns. I have a lean condition so I just picked up BP8ES's and hope to try them today or tomorrow.

 

i might of missed it but did you check the diaphrams when you had the slides out of the carbs a small pin hole will make it run lean at small throttle openings just a thought . there really should be no reason for it running so lean with the stock airbox and exhaust are the boots well sealed to the airbox. that era of bikes was very bad about having the airbox sealed. i had an 81 suzuki 850 that wouldnt even start with the airbox off . also try plugging the air inlet to the airbox give it a little gas should choke up and run rich if everything is sealed pretty well look for black smoke when doing this best of luck

 

Ive got BP7ES in it, the PO (previous owner) had BP6ES in it. I had thought of putting BP8ES in, let me know how that works out for you

I didnt really notice any problems in its performance over the trip, up and down mountains, plenty of power when i wanted it, cruised smooth.

cutlass, i really like your idea for blocking off the intake to filter, something ive done working on CNG engines, why i didnt apply it here to check out those boots i will probably wonder for awhile... ill let you know what happens when i try..
the diaphrams were flexible clean complete pliable light film of silicone grease applied seated beauties

i was thinking also i really should have micrometer-ed the thickness of the shims i used. guess i could go back to HD... but i did see in rcracermans similar post the discussion of notching the washers to make them fit which the 4mm set i got in HD just barely fit beside the notch, which makes me think, (damn, gotta pull it down again,) and that they are smaller (diameter and thickness) than what others are using

but basically im pretty sure im just missing/overlooking something. probably something simple.. its gotta be air getting in... maybe its this corn fuel BS... ill try and get at the bike some tomorrow. thanks for the responses guys,

 

Be aware of this: When throttle shaft seals dry out they can split into a series of little concentric rings, they can also ONLY LEAK when the throttle shaft IS TURNED to any degree, but seem (and test) just fine at idle.

Just a thought, wouldn't offer it if I hadn't seen it...

However, from your own description it sounds like your carbs are NOT truly clean.