Mixture Question / Rich frustration!!!!

I just did a huge carb overhaul / float adjustment (clear tube).
1 and 2 carbs are fine (Im tuning them to a slightly rich setting but they are not quite there yet) however 3 and 4 mix screws are almost CLOSED and run really rich when I open to a certain point (1/16th turn).
Now for the question. WHY??????? LOL
Im positive the floats are dead on. Im running a airbox. All the boots are good (I did the carb cleaning check with them while running... no revs).

On a side note, I ordered new float pins and seats SET and installed them during the "overhaul". When I did a comparison of the old and new sets I noticed that the new ones were a little shorter (1/16" or so).

 

Are you using a colortune plug to determine how rich it is getting? Did you put new pilot jets in when you did the rebuild? Did you replace the idle mixture screws when you did the rebuild? Did you do a sync? More information is needed....

 

By the numbers here.
I colortune to get close THEN fine tune with many plug chops.
I did not have this problem before the rebuild except for float level frustration which is why I replaced the float needle and seat ONLY.
My sync was dead on.

 

Maybe you have inlet valves not seating.

 

remedy or ideas?

 

Check and adjust the valve clearances.

How did you set your floats?

 

Bigfitz, clear tube method. Like I said, this issue of not having enough adjustment in the mix screws happened right after I was into the carbs.
I have not been into the valves yet. Im sure they are neglected but this issue only popped up after the carb overhaul.
When solving problems I was in the mind set of "what did you just do".

 

I understand; but "what you just did" was to "zero" one set of variables without attending to another. Those carbs weren't running too rich based on where the butterflies USED to be. But now you've cleaned and tried to re-sync the carbs, the valve clearances will come into play especially if a couple are way too tight. That's why the book stresses that the valve clearances need to be in spec before attempting to sync the carbs.

Also; when the carbs were apart, did you extract and replace the tiny o-rings on the mixture screws?

 

try disconnecting/removing the air breather tubes and see what results you get on it burning rich, if it leans out, then you know you have a carb problem or the breather is starving the motor for air; in example its pulling serious vacuum. i agree with fitz on checking the valves.. could not be opening and closing correctly. Just Food for thought how about the plugs, are they burning good? replaced.. whats the heat range of the plugs.

 

I did not mess with the o-rings in the mix screw.. hell, I didn't even know there were any in there!!!

 

Please read my entire original post on the plugs. I am using the plugs to determine the mix. Darkish golden brown is the color I want yada yada yada.

 

those o-rings if bad causes more air over the jets and messes up the ability to sync and run correctly.

Ok, i understand on you utilizing plug chops.. but i have seen people doing this with plugs that came with the bike and never occurred to them to replace them.. the electrode on the inside wear down over time and well weak spark causes poor ignition of fuel.

 

Check and make sure you're choke "fingers" are all engaging at the same time as well. Maybe one got bent when you had the carbs off?

 

Basics: when I start a sync I put new plugs in.
When I am done with the synch I put new plugs in.

 

I will confirm.

 

I know you are trying to help. The o-rings may be fine.


Thats a valid point IF the bike had been running BAD before the carb work.
I had PLENTY of adjustment before the carb cleaning and float needle and seat replacement.

The fact is I tore into the carbs because of float levels causing gas in the oil. This has been fixed ( clear tube method ).

I am exploring all the suggestions with much vigor here!!!!

 

Bill exactly what did you do to your carbs list everything (sprayed them with carb cleaner, bench sync, blew out the passages with compressed air, painted the bowls blue)

 

The fingers are moving in unison.

 

Bill, what you said about the o-rings and the bike running bad before the carb cleaning isn't true at all. Actually the first time I got into my carbs #3 mix screw o-ring was torn accidently. I didn't know it until I found I couldn't colortune it. The o-ring got lodged and blocked off fuel so my #3 carb was super lean and screwing the screw all the way out didn't do anything because of the block. My point is that you may have accidently damaged one in the cleaning. It can happen, I know first hand.

 

Step
1. pulled rack and disassembled.
2. shined / buffed out throttle shafts. (clunk test GOOD)
3. repaired pin holes in diaphragms with liquid tape.
4. pulled bowls off and blew out the passage on the bowl with carb cleaner.
5. pulled floats/pins/pin seats off and set them in the bowls respectively.
6. took the carb bodies outdoors and shot carb cleaner in every orifice i could poke the carb straw in.
7. IMPORTANT!! on reassembly I installed a new float needle and seat (is the seat the threaded female reservoir that the float needle rests in?)
8. reassembled the tops of the carbs and performed float hight adjustment via clear tube method and gasoline.
8. Running sync on the bike. ( 4 way carb sync on JCWhitney gauges )
NOTE: I did not disassemble the rack or go into the mix screw chamber. My issues were float related is why I replaced the parts.
***** What did I miss?

 

How did you dig out the old o-rings?

 

First you need to pull those screws to see if they are there or not but if one is missing you can use a wire to poke it or them out. Kind of depends where it might have ended up. Just something you may want to check though.

 

Poke them or hook them and pull them up?

 

I guess these are the 0-rings i need?

 

Bill if you are sure the enrichment plungers are closed and the pilots are closed and you are still getting too much fuel then you either need to close down the butterflies on those carbs or your fuel level is to high in the bowls and is bubbling up the main jet

 

Waldo, Those all make COMPLETE sense. Thank you so much.
I will continue on your points tomorrow after work.

 

Check to see that you didn't mix the two Air Jets.

 

Rick, I took my time when I did the work and prepared after reading many carb postings.
I even logged a rough but useful picture of where everything was and took the time to pay attention on assembly.

 

Those o-rings look to big to be for the pilot mixture screws, you Have to get the o-rings out & if they are squashed replace them (hell replace them anyhow) they can be a swine to dig out, I use wire with a sharpened right angle on the end (just 1/16"). Now, you seem to be reluctant to check the valves, I would do a compression check, wet & dry, to see if that flags up a problem. You must be sure of the valves before doing more work on the carbs.

 

The next carb job I do I will see what is in the botton of the mix screws for certain but, the bike ran GREAT before I took the carbs apart (still tachs out no prob). My only concern was the floats over flowing gas into the crank case. I have a rich condition that was not there before the carb rebuild.
Im not concerned with compression with it running this good. Yes I have probably neglected the shims but, I will iron that out probably this fall.
I have all the info I need to get this going in the right direction now.
Thank you all!!!

 

Bill you cant expect your engine to run the same as it did before you sprayed out the carbs and really you should check your pilot seals now rubber and carb spray dont mix. While sometimes one can get away with doing things half way it really is in your best interest not to do so. The specs for the bike are there for a reason . The adjustments that are built into the design of the engine are engineered to work together that is you can adjust the butterflies to compensate for the difference in valve adjustment but only so much then things start not working as they should. Remember the engine can only run as good as the poorest performing cylinder and synchronizing does not equalize performance of the cylinders it equalizes air pressures. Performance gains from syncronizing are the result of getting the cylinders to work within the range that the carburetors can be adjusted to equal out the performance

 

Thanks, I'm hunting a valve cover gasket and going in the carbs again this weekend.

 

I love how everyone is going through all of this conjecture and theorizing, while completely ignoring one of the most obvious factors:

CHECK THE VALVE CLEARANCES. Adjust any that are out of spec.

BEFORE attempting to sync the carbs; otherwise you're not "going in the right direction" at all. You're "shortcutting" and it won't work.

 

Thanks dude, will do.

 

Do these gauges have enough slides to do a shim swap?

 

If that's the whole set; not really. It's also an "American" set, so the metric "equivalents" on them make for some often-confusing conversion math.

I recommend a "primarily" metric set, such as KD Tools' 2274; makes the job much easier. http://www.google.com/products/catalog? ... 7&bih=837#

 

Will this gasket work? I think it looks like crap.
My original gasket looks like rubber and the one pictures looks like paper.

 

BillB, I'm pretty sure your '82 has the rubber condition gasket. the paper one shown above is for '80-early '82s which I use on my '81. i will be replacing mine today since there is a slight oil run down the hot engine.

I've got a spare rubber one thats been used but should work since there are no tears or stretches. PM me if you're interested or else talk to Len. his are brand new

 

Can your set become magnetized? Im not so sure about using steel feeler gauges because of this.

 

You can use steel feeler gauges; they won't become magnetized. I use the KD2274 all the time.

The gasket in the pic is indeed for an '80 or '81 (pre-YICS motor) your bike takes a different gasket altogether if it has YICS. The gasket for the YICS motors is a molded-rubber affair with the cam plugs molded right on. Also, with the YICS motors, you will need a new set of 'donuts' for the cover bolts. The 'donuts' are what actually push the cover against the motor as the bolts have stop collars on them.

The bike in my "valve adjustment how-to" has a YICS motor (550,) your gasket looks like that one.

 

+1

The '80 and '81 non-YICS 650 and the '82 650 Seca, which is also a non-YICS motor, use the cork gaskets.

'82 and up Maxims and Turbos use the rubber gasket/donut combo

Definitely do as Fitz suggests and get new donuts. If you don't you'll end up getting P.O.'d when you see oil leaking down your engine.

 

Well after 3-4 days of ordering parts. (I probably wont need for awhile) it struck on me what to do about this. (A solid fix often falls on me like a avalanche)

It would have to be the new float needle and seat that SEEMED smaller than the originals. (the what did you just do question helped)
I mentioned this earlier and no one pounced on it.

I need to pull the rack and put the originals back on reset the floats (clear tube) and see if the tune-ability is there.

Pilot seals are on their way from Len.

EDIT: my OLD pilot seals were intact and fine but, I changed them anyway.

 

The bike is running great now that I flip flopped back to the original hardware and reset the floats for them.
What a pain in the a##. I will post pictures of the old and new parts and the differences if anyone is interested. Apparently different does NOT mean better.

 

Ya still gotta at least CHECK your valves before you end up BURNING one.

 

The Valve Cover (Cam Cover) is Precision Engineered.

Applied correctly, you should be able to remove and reuse the Gasket when doing Periodical Maintenance.

The Hold-down Fasteners, with their Rubber Donuts is integral to the system.
They apply the pressure that assures the Gasket wont leak.

When they lose their resilience; the Gasket will seep or leak.
This is when they must be replaced.

Attempting to further tighten-down the Bolt, ... beyond where it seats ... leads to:
Stripped-out Threads on the Block, Fractured Camshaft "Bridges" and other damaged parts cracked from over-tightening.

 

A spare gasket is on its way. I didn't order the donuts though.

 

What is the technical term for the "hold down fasteners"?
Im looking for some.

 

YamPartWebList
83XJ750MK
CvrHdwe
Item# P/N Name Amt

22 90109-06604-00 BOLT 4
23 4G0-1111G-00-00 RUBBER, MOUNT 1 4
24 90109-06605-00 BOLT 8
25 4U8-1112G-00-00 RUBBER, MOUNT 2

 

Rick is talking about the valve cover bolts.

They're not just "bolts." (Look in my how-to.) They have stop collars that allow them to be tightened to a certain point, period. THEY don't actually touch the cover. They push against the "donuts" which push against the cover, and compress it against the gasket and head. If your "donuts" are old, and permanently baked in a compressed state, even a new gasket will likely LEAK.

As Rick eloquently pointed out, once you've replaced the gasket AND the donuts, the whole shebang can be re-used over and over, multiple times, without leaking.

Quit trying to "shoestring" it; some things just plain need to be replaced. How many times you wanna do this anyway?

 

So it's kinda like a re-sealable container.