frustrated and close to being demotivated

ok, so here is my dilema - It's sunny & in the 80's and I can't ride!

I'm almost ready to put it up for sale. Wishing I had fuel injection!

It's a 1982 XJ550. Rebuilt the carbs last year, and then reset the floats this year. bench sync, color tuned & balanced. Took it for a ride and it ran great.

Now, once it's warm the idle jumps up to about 3K. I can adjust the main screw till I'm blue in the face. I initially found that the vacuum line to the petcock had come loose, but it continues to do it after putting it back on.

I'm guessing it's an air leak? could it be something else?

Any help would be greatly appreciated - it's killing me to have it sit in the garage!!!

 

was it warm when you synced the carbs ? sounds like when it warms up its running lean

 

yep - it was warm... let it run for about ten minutes or so.

 

if you mean 80 and sunny warm, that would make it richer, the hotter it gets the richer we run
check the vacuum caps on the other carbs and replace that vacuum line, might be a cheap easy fix

 

vacuum leak cuases it to die or run rough. use carb spray as that is the easiest to make work. and give light squirts around the vacuum ports on the intake boots AND the intake gaskets. any drop in idle with a squirt and that's your vacuum leak. i adjusted the air mixture screws before balancing. and i ALWAYS snapped the throttle after each adjustment balance. my first times at syncing took me 5 times before i finally figured out that important step when balancing as i could never get it right.

i don't think your carbs are synced properly. out of sync carbs always idle higher as the bike gets hotter. least that's been my experience on all my bikes.

 

Do you have a four-port carbtune? Would be interesting to see the balance when it's warmed up and racing.

When I bench-synced my carbs after rebuilding I noticed how out-of-whack they were at first; with no force pulling on the throttle linkage, the 'main' carb was already cracked open due to the way the spring forces were acting. Makes you appreciate the thought that went into the design when it's running right.

 

OMG, ... I don't know where to begin.

If you find a Vacuum Leak with Carb Cleaner, ... the Carb Cleaner acts a FUEL and the rpm's INCREASE.

You have to get the Bike to IDLE with the Throttles Closed.
Closed.
Running on the Pilot Mixture, ... alone.


When the revs rise here’s what to do...
Keep the RPM's at 1,100 by reaching under the Carbs and lowering the Idle Adjustment Knob.
Stay close to 1,000 rpm’s at all times.

If you can't get the Bike to IDLE below 1200 with the Idle Mixture Rod turned to where the Throttles are shut, ... the Bencnh Sync was done incorrectly and you'll have to reset the Butterflies closed. (( Use strips of 3X5 Card to Bench Sync))


"Tweak" >>OUT<< ... the #-1 Pilot Mixture Screw listening to the Engine and Exhaust note VERY Carefully.

**>>Keep turning the SCREW ~> OUT >>IF<< the RPM's continue to rise.

At some point ... The RPM's ~~> will NOT continue to rise.
Remember this Point. You have to come back to it.
At THIS point:
>>>||| MICROSCOPICALLY continue the Turning OUT...

UNTIL <~~

The Mixture gets TOO RICH and the Bike:
Coughs
Misfires
Burps
Runs rough
Etc.

>> STOP <<

THEN <~~ Get ready to make a CRITICAL Adjustment.
Pretend you are about to move THE SECOND HAND on a STOPWATCH!
One FULL Turn would be 60 Seconds ... right?
OK.


Turn that Pilot Screw ~~> IN <~~

Two (2) Seconds ... maybe Three (3) (Seconds***, small, a (my-nute amount)
Don't go beyond four.

Run fans to keep the bike cool.
Throttle it up and let it idle.

Adjust the IDLE rpm's with the Idle Adjustment ROD.
1,100 Max

Tweak #-2
Just exactly like #-1

(If the rev's exceed 2,000 ... back-off the IDLE SPEED ROD More)

Then finish-up doing #-3 -&- #-4.

When you are done ... TWEAKING ... you will need to Road Test for THROTTLE RESPONSE.

IF...

You are Idling, say, at a Red Light and when the light turns green and you take-off ... (Getting “Out-of-the-hole”) … and, …

The Bike ~> BACKFIRES a little bit before the Power comes on:
Your LEAN
The Pilot Screws need to be:
Tweaked OUT
Two (2) Seconds. ((Degrees))
Chart where you are at from this moment on … +2 Degrees

IF...

You are at the light and take-off...
The Bike ~> HESITATES for the slightest bit before the Power comes on:
Your RICH
The Pilot Screws need to be:
Tweaked IN
Two (2) Seconds.
>>>(Almost not turning the screw at all. A nudge!)<<<

Fine-tuning will be complete when you have Tweaked-Out the Backfire or the Hesitation during Further Road Testing.

All further Tweaking is to be done in increments of:

Two Seconds at a time.
Go find a closed Industrial Park and do it all in one sitting.
Have somebody put the tools you need in a sack and follow you over there in the car.
Don’t forget a Flashlight.

Backfire = Lean = OUT

Hesitation = Rich = IN

Go for it!

Get Tweaked
Watch your Plugs and treat each Cylinder individually.
Read the Color of the Plug on the Center Electrode’s Ceramic Collar.
Too Dark (Beyond chocolate brown) Tweak IN: 2-Degrees

Too Clean: (Clean or no coloration) Tweak OUT: 2-Degrees
As you Tweak individual Carbs for the right Mixture … Watch the Plugs coloration at the Center Electrode Ceramic Collar.

CLEAN: BAD. Too Lean. Tweak Screw OUT for MORE Fuel.
Although the Bike will run superbly Lean like that … it’s a dangerous condition that can HARM the Bike permanently.

Light Tan: Lean but OK.
This is a Power setting.
The Mixture is burning Fast making big power. You’ll have fast acceleration with the Plugs a light tan. You must monitor the situation and keep an eye on the Oil Level. If your Oil starts disappearing and you don’t have a leak … you are still too Lean.

Light Brown: Normal. Nirvana.

Dark Brown: Rich.
Most people like to have them at the Dark Brown Mixture setting.
The Engine makes good smooth power and cruises really nicely, staying cooler than the Lean settings.
If I am tuning someone’s bike for them … I set them closer to Dark Brown so they are insured against Ring and Valve damage.

 

carb cleaner KILLED my bike. that's why i replaced the intake gaskets. checked with carb clean again and now i have no leaks.

but i went with heavier squirts. not just a dab.

 

Thanks everyone.

I'll start with buying new caps and vacuum line after work tomorrow.

I'm almost positive I did the bench sync correctly. Took my time and double checked each step along the way.

I think I'll pull the rack again, do the bench sync again, set the mixture to 2 3/4 turns, and then follow RickCoMatic's procedure.

I'm suspecting the mixture & balance as the bike seemed to run ok before I started with the color tune. I can't believe how frustrated this has me. I'm close to taking it to the shop!

Would it be worth the investment to purchase a 4 port carb stick? seems like it might be a bit expensive considering how often I'd use it...

 

I assume you mean the idle adjustment screw under carbs 2 and 3.

So Rick says... re-sync on the bench. I guess that is what I was getting at... the butterflies can be tricky to get all aligned perfectly. Sounds like another bench sync is worth it.

PS - I haven't bought the four-port carb stick either, made a two-bottle sync tool with ATF fluid. Seemed to work okay on my Maxim-X.

PPS - I'm from that neck of the woods... you're near Buffalo, right? Grew up in Brockport, nearer to Rochester. Miss that part of the country sometimes.

 

i bought 20 ft roll from home depot. $3. cut in half. so you have two 10 ft sections. then filled with ATF from a quart bottle with a nozzle i could stick into the tube. bend the tube so it's u shaped. and filled about 2/3 full. ATF is quite light so you need a bit to make it heavy.

i hooked to the intake ports and draped over the handle bars. with a weight to pull the tube straight. adjust the carbs till the fluid bounces level between each side. so one tube h ooks to 3 and 4. the other tube hooks to 1 and 2. fluid level don't have to be equal to each tube. so don't worry about having the same amount. once the carbs are adjust as a left and right set. then remove one of the tubes. cap off 1 and 4 cylinder vacuum ports. and put one tube onto 2 and 3. then adjust the middle screw to sync both left and right sets together.

my sync tool cost $3 for the 20 ft roll of tube. and $3 for a quart of ATF. or any type of oil will suffice. just as long as it's a darker color so you can see it better.

can't get any cheaper then that for a sync tool.

follow ricks advice for the air fuel mixture before syncing.

 

After this Article first appeared, a XJ-Bikes Member "Refined" the process for me.
He said: Adding an Aquarium 4-Valve Gang Set to the process eliminated a lot of the fumbling around.
Here's the VERY BASIC Old School Method.
But I confess.
I went out and bought the Aquarium Valves and threw-out the Golf-tees.

That Aquarium Valve set makes the process as easy as 3.1416.
I suppose it won't be too very long before somebody comes-out with a Carb Synchronizer Tool that's all digital, solar powered, with a combined LED and numeric read-out, that will fit in your shirt pocket. Until then; columns of mercury or the handy, new, stainless steel-weighted synchronizers are the way to go.

But, for XJ-Owners, who are only going to sync-up the carbs every couple of decades ... or, for those who don't want to lay-out seventy-five to a hundred bucks (or more) for Carb Sticks or a CarbTune meter ... buying an expensive meter, or one filled with mercury just isn't practical for as often as you'd ever need to use it.

So ..., how are you going to be able to get your Carbs synchronized without buying the Sticks, or taking your bike to someone who's got sticks, or to a place that charges big-bucks to do something you'd do for yourself ... if you had the means?

! ! ! ! ! ! ! ! ! !

Easy ... Just hop in RickCoMatic's Time Machine, and come back with me, to the time before Carb Sticks; when you had to "Match-up and Sync the whole rack ... with ONE Vacuum Gauge!

The Old School Method
Single Vacuum Gauge Synchronizing of Carburetors
by: Rick Massey
Special to XJBikes.com
All rights reserved.

First, you need one vacuum gauge. (There's none better than the one sold at Sears for $19.95) and your home-made YICS tool.

A couple of Electric Fans to keep the Old XJ from overheating while you do the tuning-up. Two. Aimed at the Engine. High speed for Max cooling!

You need some vacuum line. Get ten or twelve feet. You'll be making-up lines to run from each carb out to the side of the bike where you'll hook-up the Vacuum Gauge.

You need a few small, hollow, plastic-barrel vacuum line connections. (Those little things you use to plug one vacuum line into another.)

One medium-sized fuel filter; with ends that will fit the hose.

One red plastic spray tube ... like the one taped to a can of carb cleaner.

Four regular Golf Tees. (Just steal 'em from your dad's golf bag)

5-minute epoxy.

Masking tape and a "Sharpie"

OK kids ... Let's ROCK!

Prep:
Fabrication of the "Vacuum Restriction Valve." (Absolutely necessary)

Take the skinny red tube and run it through one of the hollow, plastic hose connectors.
Seal that hollow connector with epoxy; leaving a length of the red tube extended from each end.
(This fabricated little-metering device will be the all-important "Vacuum Pressure Restrictor" that will allow you to read the vacuum gauge without the extremely WILD fluctuations on the meter you'd get if you tried to get a vacuum reading without it.)

When the epoxy hardens; cut-off the extraneous ends of the red tube -- flush.

Using a short length of vac line ... attach the restrictor to one end of the medium-sized fuel filter.

(Now you have a restrictor attached to the fuel filter. You just made what you NEED to get the needle on the vacuum gauge "Quieted-down" enough to get an accurate reading without the meter being so wildly fluctuating as to be useless. You have Baffled-Restricted-Regulation and this softens the harsh, impossible-to-read fluctuation, the indicator would have, without it.)

Hook-up and Sync:

The rest is by the book.
YICS tool inserted.
Four Vacuum lines run from the Carb Intakes over to where it will be convenient for you to connect these four lines up to Vacuum Gauge ... each marked with a little tape label for one through four. Stick the golf tees in the ends of these lines ... and get ready to sync the carbs.

Attach your "Old School - Baffled Restrictor" to the vacuum line coming from Number - 3 with the red tubed restricted end plugged into the vac line coming off the engine.

Plug the Vacuum Gauge into the Fuel Filter end. You're officially restricted and baffled for testing ...

So, let's do it!

Run the bike and get the vacuum reading of Number 3 (Three) ... to check for good vacuum on three and to observe how the needle of the gauge is still going to MODERATELY "Vibrate" as it measures engine vacuum.

Sneak the rev's up to 14 > 16-hundred rpm's and the fluctuation will become rapid enough for you to read the vacuum that the hole is pulling.

Mark the gauge face with a short strip of masking tape and mark the tape with a check-mark. Don't let the tape strips block you from seeing the vacuum gauge needle during the sync.

Authors Note:
It's a good idea to practice pulling a golf tee out and covering the hose with your thumb. This will keep the engine from stumbling and possibly stalling.

Checks and adjustments:

Read the Vacuum being pulled by Number 2. Mark maximum vacuum drawn by 2 with line of tape.

Get your magic fingers ready to do the "Carb-Shuffle!"

Pull-out the baffle and block the vacuum with your thumb until you can insert the golf tee you have ready between your lips or behind your ear.

Measure the vacuum being drawn by Number 1. If the max vacuum being drawn by Number 1 is NOT the same as you have MARKED for Number 2 --ADJUST the SYNC SCREW on Number 1 ... until the Vacuum drawn by ONE is the SAME as the Vacuum drawn by TWO!

Two down ... two to go! But, here's where it gets tricky.

Plug-in to Number 4. Set the Vacuum drawn by Number 4 -- to -- the BASE Vacuum you measured for Number 3. (Actually check 3 again ... adjust 4 to match 3 -- because 3 is the Base Vacuum Port, has NO sync screw adjustment, and usually has the petcock vacuum hose connected to it.)

At this point you start TWEAKING. From here until the rack's in-sync ... it's all down hill!

The engine should be sounding pretty darn good; right about here. But, we need to finish it off!

Just hook-up to Number 2, now ... and bring the vacuum being drawn on Number 2 -- UP or DOWN to match the value of Number 3.

They'll be no need to adjust Number 1. Number 1 is connected to Number 2 and goes right along for the ride when you sync Number 2 to Number 3 ... and you ...

HEAR the results of synchronizing all four of your carbs with only one vacuum gauge.
Let what I have outlined, here, be your guide ... but, don't be afraid to get creative with where to have the golf tees ready to pop-in the lines!

When you wrap-it-up ... the One - through - Four ... Final Measurement should be all right on the same value -- right across the board.
Yes? DONE!
No? Tweak until you nail it!

Can you believe that we used to have to do it this way? Compared to the MotionPro Carb Sticks -- It's like being in Bedrock ... spending a little time with Fred and Barney doin' a little Stone Age Tweaking'!

Editors Note: Since first published this process can be done even EASIER, ... Using a 4-Valve Aquarium Air Hose Device allowing you to close-off the various lines and do much faster balancing.

 

if you have one handy. could you post a pic please, rickomatic. i'm always game for something that might work better then what i've been using.

 

Hey Just a question but I have a Glycerin filled vacuum gauge, and am wondering if it's worth the headache of trying? I was just thinking, but it seems it goes to 30" in too far of increments? also what is the "average" of vacuum to be pulling? in Hg

 

What do we need a photograph of, please?

The Gang Valves?