Black sooty smoke, smells like gas.

I rebuilt everything possible on my maxim, which now has a seca tank. I rebuilt the carbs, returning all the jets to what yamaha says, I have all my valves in clearence after doing a complete head job. and my bike still runs rich. I cant figure it out. I have a carbtune pro and a gunson colortuner. But no matter what i do its always rich.
If i use the choke, it kills the bike and i have to turn the idle adjusment screw down to cold start it. and it the exhaust ALWAYS smells like unburnt gas, wether at idle or 45. and will bellow out a cloud of black smoke if reved in neutral.
Please Help. I've put alot of hours into this bike, and now I'm stumped.
I'm considering smaller idle fuel jets, and possible pod style air filters to compensate, but id rather fix the problem and stick with my stock airbox.

I have a brand new gastanks cap and rebuilt my petcock, so thats no longer possible issues. Im not sure my floats are set 100% perfect.

My other thought it when rebuilding the carbs, when it came to the choke "valve", i may have mixed up the order of which goes in first, the washer or o ring, could that cause problems like this?

Any help is appreciated.

 

From what you said, I'd suspect there is something wrong in the enrichment circuit ("choke"), it acts like the choke is always ON even when it should be off. I don't know if it is because you out them back the wrong way. I'd be surprised if all of the four circuits would be improperly cleaned at the same time.

All four spark plugs are black?

 

I suppose your air filter is new or clean and that there is no obtruction in the airbox? Sometimes small animals make their nest in there.

 

Is your oil fresh, or gasoline contaminated from previous issues??

You MUST have your floats at the correct level.
You can check this on the bike, but - you have to ramp the front tire up around 10 inches, and hold the bike level.
Or remove the carbs.

Completely remove the air filter for a quick test.

If you have fouled the plugs - - they will continue to foul you, like a Soviet Russia joke. You need a set of brand-new plugs.

If your choke is not COMPLETELY shut off, well - there's a problem.

Do NOT try to fix this problem with smaller jets, or PODS, you will only get further lost in the woods.

Bear with us, give us more info, and you will be tuned up in days.

 

quibois: Im thinking the enrichment circuit is the best idea. Ill dig into it in the next few days and see exactly what was done. to be honest, i paid a friend to rebuild my carbs due to the horror stories ive heard, and he had a seca.
And yea, the airbox is filter are completely clean. i had a rubber tunnel that led down into the airbox and i removed that even for more air flow.
And yea, all 4 are black, but cylinder 3's plug is always a little less black.

Time: Oil is fresh after petcock issue, i had to fixed all that. I clean the plugs and have replaced them a few times now. Ill refrain from any serious changes until i feel we can track this down.

 

my guess would be high float levels.

CN

 

The main jets shouldnt effect the idle, the only operate when vacuum is lost to the front side of the carb and the vacuum pistons slide upwards(thus pulling the needle out of the main jet).

Double chack the float levels, all you need is a 1-2ft long section of clear hose and a flat bladed screwdriver.
-Put the bike on the center-stand
-Attach the clear hose to the drain on the bowl of carburetor 1. hold the rest of the hose upwards over the side of the carb. the hose will fill with fuel equal to the level inside the bowl.
-Now measure the same reading for carb 1 against carb #4, this will tell you if the bike is level or not!
-If the bike is level(carb one's level was equal to the same spot on both carb 1 and 4) go ahead and plug the hose up to the other 3 carbs and check the fuel level in reference to that specific carb.

http://www.xj4ever.com/setting%20fuel%20levels.pdf.


Did you check compression? Low compression would cause rich symptoms. You can rent a compression tester at most autoparts stores and get a full refund.

 

I respectfully disagree - -
This won't determine a left - right level , as there are 4 floats.

The issue is to get the bike around 15 degrees "nose-up" so the carbs are level in a fore-and-aft relationship, level to the ground.

And this is just for checking - - you can't adjust carbs on the bike.

(you could level the bike, left-right, with a level placed on the frame)

 

You would be correct that carb 4 and carb 1's relative float levels have no bearing on the bike being level.
However, if you measure the cylinder 1 carburetor float level relative to both cylinder 1 and four you will be able to accurately determine if the bike is level. You dont disconnect the hose from #1 and reconnect to #4, you simply reach the hose from carb 1 and hold it to the side of carb #4

 

Trying to check float levels with the carbs on the bike is an exercise in futility.

Float levels: http://www.xj4ever.com/setting%20fuel%20levels.pdf

Elaborate, please. And did you check compression now that the motor's back together?

 

". . .You dont disconnect the hose from #1 and reconnect to #4, you simply reach the hose from carb 1 and hold it to the side of carb #4. . . "

Got it - you're basically using the clear tube as a spirit level, of sorts.

I've gone so far as to check all 4 with the engine running, just to see the results of my work.

 

I havnt done a compression check, I put a new head gasket and seated the valves. guides seemed in good conidition so i didnt bother.

but high floats seem pretty likly, i had to adjust them last year because one carb 4 wouldnt close and would constantly dump gas into my engine.

ALSO, is there suppose to be an oring or any kind for seal at the bottom of my starter enrichment needle? It seems like there should be for a solid seal, but theres nothing.

 

Yes - there is a spring that rests against a tiny washer that pushes against the "O" ring - - all available from Chacal - - delivered almost instantly.

 

Im talking about for the choke, not the fuel air mixture screw for tuning.

 

nope, no o-ring for the cold start plunger. it is a tapered seat. check the mating surfaces for pitting from corrosion or scratches that might hinder a good seal.

CN

 

I just checked on an Hitachi spare rack of carbs I have here, and there is no o-ring nor seal at the bottom of the enrichment needle or plunger. It seems that the shape of the needle and the hole down there are intended to do the job.

 

Ok, its not the choke/enrichment circuit. I got different bowls where the drain screws arent all stripped, so ill be able to get my float levels proper.
Its alright to do this proccess with the carbs off the bike right?
It would make it alot easier to adjust.
I got some old intake boots that are cracked, so i was gonna drill those onto the side of my work bench and hook the carbs. that give me easy access to the bowls, and i can gravity feed fuel off my work bench.

 

make sure the choke plungers are all the way down and you can see light between the plunger tops and the fingers that lift them. then adjust the choke cable so when it's off you have some slack in the cable.
my floats are real high and i've never seen anything like you describe

 

yes you will have to take the carbs off the bike to make adjustments to the floats. you can only check the float levels when the carbs are on the bike. great idea using the old intake manifolds to hold the carbs.

CN

 

You can wrap one end of the brass enrichment plunger in a scrap of cloth and clamp it into the bit of a drill. Makes polishing them to mirror perfection a breeze. You can purchase wire brushes for the bores of firearms that will fit inside of most places like the enrichment plunger bores.

You may have to replace the float needles and seats, they are prone to wear.
I would also check the pilot screw O-rings, especially since the carbs were dipped. Make sure to count how many turns tightening until the screw bottoms out before you remove them so you can return them to the same setting.