pull the plug wire and no change

he Ya'll

So rather than say my idle is high, or where can I get a cheap sync tool, because I rebuilt my carbs and picked up an aftermarket ignition through chacal - I would like to ask:

What does it mean if I pull the #4 (far right cylinder) plug wire while the bike is running and there's no change is idle pitch. But of course there's a change if I pull any of the other wires.

I can see spark if I stick screwdriver in the plug boot and if I hold the plug up to a valve cover bolt. float level is right on. The idle comes down if I push on the sycn screw between 1&2 (far left screw/cyl,carb).

so, who has the cheapest sync tool?

I guess I could also ask - does anyones airbox boots really meet the carb mouth's completley??? Mine only reach the tips of the carbs


Thanks!

 

Check if the downpipe is getting hot - sounds like it's not firing. f its not firing could be fouled may not be getting gas.

Sync shouldn't make it not fire. cheapest tool is the 2 bottle rig (search will find instructions). Personally I use a vacuum gauge from harbor freight <$15

My boots go over the carb lip fine. Make sure you don't have the carbs in the manifold too far and your air boots are fully seated in the airbox

 

Thanks Bill

The carbs get 'sucked' into the intake manifold and seem to only fit in one position. I'd have to ask someone pry them out a little to get the airbox boots all the way over the carb lip. the air coming out of the right exhaust is definitly cooler than the left

I'll be doing the propane check thing tomorrow, I can't wait to see how that actually works! and thanks I bought the supplies for the 2 bottle sync tool. It'll all unwind tomorrow.

 

Are the airbox rims in the groove of the boots? if so you should be able to slack the air box brackets & force it forward slightly, you are only looking for 1/8th or a 1/4"

 

yes the boots are perfect, but the face of the airbox is slightly bent or concave 'in' a little. going to do the propane thing now. Can I sync if there's an air leak? I'm guessing no

 

Not advisable it will make a big difference.

 

ok so I seen the 'fog' of the propane going all over the intake area and no rise in idle. I felt the down tubes of the 3 firing cylinders and they got hot real fast. I was able to keep my hand on the 4th for another minute or so. I think it's firing 'some', I may have been feeling transfer heat but the damn response is so good I can't beleive that's 3 cyl's.

so the idle is still hight at 3500 so i'm going to play around with the sync's now I guess. I have no idea why it wouldn't be firing like the others

Thanks Bill

 

Try swapping the # 4 plug with one of the others - maybe it got fouled.
If you didn't see a rise in RPM you may have a decent seal on the boots after all

 

ok put a new plug. I did another test; reved it up to 4 grand and then pulled the plug - no change in rpm and then left the plug wire off and it still behaved the same...I knew sinking the carbs wasn't right so, OFF WITH THE CARBS. now that I have the carb apart, I don't know what I'm looking for. I pretty much have it all apart. spraying....... I was hoping to find Something in there but it looks good God Dammit

 

Ok I see a piece of brass under where the 40 pilot jet used to be, the second hole from the needle valve. does that come out?

 

so it's all back together and the # exhaust pipe is still cold. Work is getting in the way so I'll have to pick this up in a few hours hehe.

I noticed the top sync spring is completely squished for this carb, when I did my bench sync weeks ago I didn't bottom them out first.

Could that be a possible cause for a cylinder not to fire??? and I have good compression. Mind you I bought the bike not running and I see fresh red silicone at the heads and cylinder so maybe it's timing or something? I'm almost fresh out of ideas.

a buddy recommended spraying starting fluid in just that one cylinder but I don't know how. Hhhmmmmmm maybe through the vacume port/nipple

Please let me know your thoughts guys
Thanks

 

hitachi carbs

 

When you pull that plug on four after its been running, does the tip appear to be wet?? Or oily??
-SLK

 

If your Sync Screws are "Squished" ... That's a sign that someone has been trying to get the "Four-hole" to fire.

Instead of Pulling the Plug Cap ...
Do this.

Start the Bike.
Pull-off the Rubber Blocking Cap to the Manifold Vacuum Inlet.
Put your finger on the Manifold Opening or hook-up a Vacuum Hose and stuff a Golf Tee in the end of the hose to seal-off the line.

Get an Ear Syringe -- (Like the one pictured):

Fill is with Clean Carb Cleaner you squirt from the can into a container.
Run the Bike.
Bull the Golf Tee and let Carb Cleaner --> "Dribble-Out" from the Syringe into the Vacuum Line.
Listen to RPM's.
If the Four-hole "Fires" when you "Dribble" Carb Cleaner to it:

1. The 4-Hole isnt getting enough FUEL ... - OR -
2. The 4-Hole is getting WAY too much AIR ...

Test:

With Engine Running:
Hook-up Vacuum Gauge --> WITH -- Inline Restricter:
(Inline Restricter --> Union w/ Carb Cleaner Red Tube Epoxy'd to reduce flow)

Measure Manifold Vacuum on Number-1
Move Gauge to the 4-Hole
Measure.
Readings are CLOSE = Fuel Supply Problem - Carb Related
Redings VARY Greatly = Leak causing Low Vacuum

IF --> 4-Hole "Fired" when you "Dribbled" Carb Cleaner to it ... Problem is a Major Air Leak.
Probably the O-ring/Gasket at where the Intake Manifold seats to the Cyl Head.

Do Not BREAK Manifold Cap Screws in an attempt to rectify this leak.
Use RTV Sealant.
Carefully SEAL Manifold to Head running Bead of RTV all around where Manifold seats to Head.
"Smooch-In" the Sealant between the Manifold and Head.

Retest.

 

Ok, got the 4 cyl's fired up - Thanks Rick

I know it sounds stupid but, after sync'n the carbs the bike starts rougher and sounds chopier than before. maybe turning the air mixture screws will fix it followed by another sync.

so what tells me which way to turn the air mix screws (next to enrichment circuit)?

 

Well in is leaner out is richer Most of us use a colortune to get it real close then read plugs to fine tune.

Lacking a colortune you can read the plugs. Tune it - take a few miles ride and look at the plugs. Looking for a kind of paper bag tan. Lighter than that too lean - darker too rich.

 

Get an accurate <- Accurate - Mechanics Ruler.
Take an Old-style Glass barrel Fuse.
Measure -> Precisely <- 9/32nds of an Inch from the end of the Fuse.
Mark it with a THIN Line scribed all the way around the metal end.

Set the Mixture Screws using the Fuse "Depth Gauge"
Set the Fuse in the Mixture Screw Hole and set the depth of the TOP of the MIXTURE SCREW to be --> 9/32nds deep.

Turn the MIXTURE SCREW In or Out until the SCRIBE LINE is LEVEL with the TOP of the Flat Carb Body where the SCREW Fits.

How was that for Quick?

 

OK I'm going to do what Rick says (how could I not!) and then do the color tests. From what i can remember the plugs have been brown paper bag color through these hard weeks

 

Brown Paper Bag color is a GOOD color.

Treat the Holes like you are looking at each one through a microscope.

A little Tweak IN ... on this guy ... OUT on another one.
Don't mess-up a good base tune.

 

rick in noticed you mentioned not to break the manifold screws. when swapping the manifold boots, is there anything recommended with reinstallation?

 

Hey Rick, since I replaced my fuse box with a new one from chacal I had some old barrel style fuses laying around. I measure that 9/32 is above the metal rim and on the glass.

The bike for the first time is running great, not perfect but great. to seal the carb boots the best I can I pulled the carbs out 2mm from the intake manifold then tightned the intake boots. Then had a friend pry the airbox forward while I tightned the air box boots.

Now, once I figure out how to mount these new coils I can ride the lil bastard then do a plug color test. Thanks again

 

Sounds great. I always forget about Rick's fuse trick - it seems to give a great stating point. Glad to hear you are making progress.

 

so I made it to the corner and my airbox started leaking oil. I guess the crankcase was overflowed by the pri.

But I KNOW my carbs didn't overflow when they were sitting on the bench and the bike while the gas tank was on the shelf on Prime. I guess the vacume had an effect since it was still on prime and with a vacume source.

Oh well, I have to drop the oil now...

 

Hey Guys,
I had this same problem with my number 4 cylinder as well on my XJ900. It was a real pain trying to ride the bike when it was running on three cans! My old 1980 XS850 was a gem of a bike, and it ran all day on that triple engine...from San Fran to San Diego and back over a weekend and didn't skip a beat...but I digress. Anyway, my dumb ass was so happy months ago that I finally put an engine in the bike (the old one has a bad started clutch thingy, that made that God-awful noise when trying to start) that was running decent. I didn't bother tightening up the carb boots going onto the airbox, and thought it wouldn't make much difference. Ha! I was sure wrong. I spent several hours being stuck out on the road (once in the rain) trying to get the bike to start again after running on only 3 cylinders. My point is that after I loosened up that damn hard to move airbox, I reached inside and pulled out all 4 boots. I then tighten the daylights out of them onto the back of the carbs. Then I pushed forward on the box and snapped all the boots back in place. Once it was all tightened up and started, the right exhaust started smoking for about 10 minutes. Burning up all that gunk and unburned fuel and whatever was in that 4th cylinder. After that number 4 pipe started getting hot, and the bike was running like a raped ape! (LOL).
I was pretty lucky that I found my mistake. However number 4 is still the last one to get hot. I think my carbs are a bit out of sync, but riding this thing reminds me of my old 1979 Suzuki TS100 days. Feels like an enduro burning up the streets like a kid again.

I just bought a naked xj650 turbo from a custom dude out in Vegas off Ebay. It looks like a real hoot. Check it out yall and tell me what you think: in case the link doesn't work here's the Item number: 220414328307

http://cgi.ebay.com/ebaymotors/ws/eBayI ... MEWNX%3AIT

Keep the rubber side down gents.
IB

 

Bill, actually not so good. the fuse thing doesn't work for me beacuse the metal fuse cap is too short, the glass would be level with the top of the carb...

Rick should I be looking for a different fuse type than what was standard w/ my 82 XJ?

So I drained my gassy oil and filter, put new oil and started the bike. It's bogging down bad, can't give any throttle input at all(gerrrrrrrrrrrrrrr here we go again). So I'm thinking I did the carb sync with too much drag on the motor since the case was overfull, so I'm doing a carb sync, terrible terrible terrible. I'm at about 120 hours on this thing and I've just about had it. it was running so nice and i can barely get it started now. So I'm trying the sync with the tank proped up and the vacume connected to the petcock - instead of the tank on a shelf with a long tube and the vacume on the intake manifold blocked off, and the petcock on prime. BUT I can't get to the damn center sync screw between 2 & 3. what the hell kind of a screw driver exists for this - jeeeze. I think I need to walk away.

 

Ok so I did a sync, 4 to 3, 1 to 2, then 2 to 3. annoying because I had to keep blipin the choke for it to stay on. So I can start the bike but can not give any throttle input whatsoever. It was just running great last night and this morning! finally got my air boots on tight, all cylinders firing, carb rebuild, float height is good, new ignition.

The petcock, rebuilt it. If the selector is in the ON position, shoud I be able to pull vacume with my mouth and then see fuel?

SORRY FOR ALL THIS GUYS but I'm at my end

 

I hat my life. All of a sudden the 10A ignition fuse keeps blown as soon as I start the bike.

 

for kicks and giggles adjust your idle screw open a little fatrther.... i have run into this before... you may also want to have a look at your float needles / float hight if they arent shutting off the fuel.

not to discourage you but i did mine a few times and still dont trust them completely

 

Not sure what you mean by the fuse cap issue - Ricks' suggestion is to use the fuse as a depth gauge - you could use a straw, toothpick, whatever.

Mark it to the depth Rick specified and use it to set all 4 idle screws to the same depth. Should be a decent starting point for you. Then you can tweak from there.

 

ok so the fact the glass is there doesn't mean anything - good. I'll use something else like you suggested - thank you

any comments on the petcock question above? I really think I have a fuel input issue...

 

OKAY for those of you who are tuning in today. The bike is running great with the fuel tank on a shelf and all 4 vacume ports capped on the manifold. I put the petcock selector to ON and turn it to Prime every 30 seconds or so and the motor runs great.

So I rebuilt the petcock with chacal stuff, how do I check it's functions? I tried pulling on the vacume line with my mouth and seeing if fuel comes out the outlet and no dice. shouldn't it?

about the blowing fuses, I think I narrowed it down to the relay or whatever that is just above the carbs but it's gotten so bad now that when I turn the key the fuse blows. So I'm at a stand still... going to the manual

 

Yea you should be able to get fuel by drawing on the vacuum line.

 

You can use a Drill Bit wrapped in masking Tape.

But, there is a NEED for Precision.
Once you get into the Tweak Zone ... Moving the Screw a couple of Degrees either way can make an appreciable difference in the Mixture.

 

Screw in to lean, out to enrich.

 

IT'S ALIVE! THE FIRST RUN EVER again after 23k. the fuse was blowing because the aftermarket coil bolts were too close to the low tension wires.
I sync'd the carbs the best it would (I think it's true that the sync should be when the liquid stops, not when it's the same in both bottles, using the 2 bottle method. I put the liquid to the same levels anyway using the sync screws and adjusted them so they would stop fluctuating, but I could make them stop fluctuating when each bottle is a different levels if i wanted to). That was off topic - sorry

anyway, I ran the bike on Prime, I think I have just a little gas in the oil, oh well, I'll change it again tomorrow. The bike is running well, a slight hesitation. Pulled the plugs after a 7 min run and #2,3, 4 are white and # 1 is black. So I'm goin to screw the mixture screws IN for 2, 3, 4 and OUT for 1.

I guess a quarter turn each.

That's it for me today, I'm completely spent.

I don't get fuel when I pull vacume so I don't know what that's about. The Haynes manual doesn't say how to troubleshoot or check it.

 

Black is rich - IN to get leaner Turn 2,3 4 OUT and 1 IN

Not a quarter turn - think degrees - turn them 1 or 2 degrees and retest and repeat as needed. Rick has a great post showing the "zone' it is a few degrees of turn you can blow right through it with quarter turns.

 

The Manifold Cap Screws are cheap, soft steel.
IF you get them out ... REPLACE them!
Use an AntiSeize Compound replacing them.

If their Seized leave them alone and work-around taking them out.
If you are going to do Head work ... anyway ... you should consider having a Machine shop deal with any ones that are broken removing Manifolds.

If you have successfully removed all of them, ...
Re-tap the holes and treat the Threads with AntiSeize.

Removal of a Seized Fastener.
Dremel Tool.
Grind-off the Cap-screw's Head.
Remove the Manifold.
Super-heat the headless fastener to cherry red as close to the Head as you can with a Propane Torch or MAPP Gas. Other gases will create temps dangerous to aluminum.
Let cool until the red disappears and try removing the fragment.
Good luck.

Something NEW!!!

SEARS is advertising a Confined-space Heavy IMPACT Hammer.
I know I'll be giving it a try with one of those baby's before long.

 

I'd like to see Ricks 'zone' thread but I can't find it using the search function. can someone past a link? I'm really interested in seeing the '1' or '2' degree turn beacause there's 360 degrees!

Bill is it possible you meant like 1 or 2 hours on a clock? and if I blow by the sweet spot, worst that happens is that it gets richer and richer or leaner and leaner, correct?

 

yup it will get leaner or richer is true.

So you can see the "zone" is about 8 degrees. Yes it is hard to turn 1 or 2 degrees but you need to think in nudges of the screw not quarter turns.

 

holy crap haha - thanks! I feel bad for the plug threads with all that checking. Ok I'm going to try to get that brown paper bag color right now and then a final sync and post results.

 

After the YAMAHA Exhaust Gas Analyzer's broke-down and got pushed out of the way in most shops. And before the Colortune Plugs came along. We had to rely on "Listening to the Engine" to find the area close to where the Cylinder was thought to be tuned.

The process was all done "By Ear."
With the Pilot Mixture Screws "Preset" using either Turns-Out from Bottom or a Depth Gauge to set the Mixtures to allow the Bike to "Run" the Mixture Screws got tweaked.

In order: 1, 2, 3, 4 doing just one at a time.
The Mixture Screws got turned IN until the Cylinder misfired.
Then, the Mixture Screw was turned OUT ... very slowly, listening to the performance of the Cylinder.
SLOWLY <-- Slowly turning the Mixture Screw OUT listening to the Cylinder's Performance and the Engines RPM.
The Mixture Screww is slowly brought OUT as long as the Cylinder is FIRING OK ... and/or ... the RPM's CONTINUE to RISE.

The RPM's will rise and continue to gain RPM's as the Mixture being created is making POWER. (Good Mixture)
Then, ...
There will come a FLAT Spot. A Plateau. Where the Screw is being turned OUT; but, there is NO further Increase in the RPM's.
SLOWLY <-- Slowly move the Mixture Out ... Recognizing that NO Further Gains In RPM's is happening.
SLOWLY <-- Bring the Screw OUT

UNTIL

The Cylinder begins to MISFIRE because the MIXTURE is TOO RICH.
At this Point ... Just where the Hole begins to "Putter" )
(Zzzzzzzzzzzzzzzzzzzzzzzzzzzzzzzzzzzzzzzzzzzzzzzzzzzzzz) Good Idle
(Zzzzzzzzzz...zzzzzzzzzz...zzzzzzzzzzzzzzzz....zzzzzz..zzzz) Miss/Rich

Tune the Putter -- OUT -- By Leaning the Mixture IN --> SLOWLY
Until you get the Hole back to:
(Zzzzzzzzzzzzzzzzzzzzzzzzzzzzzzzzzzzzzzzzzzzzzzzzzzzzzzz) Steady/No Miss

Repeat: 2, 3 and 4
You have reached a Spot that sustains good Idle
BUT <---
Might be TOO RICH for allowing seamless acceleration without bogging.

If the Bike Boggs-out ...
Turn in the Screws 1, 2, 3, & 4 ... the width of a Nickel.
Test.
Jockey the Throttles and run the Bike above 4,000 RPM's

Begin Individual Cylinder Tweaks according to Plug Color.
Advance testing to include High-speed-load Plug Chop.
You should wind-up with each Hole within the Fine Tuning Zone relatively quickly.
One or two rides.

 

having a hard time getting the color to change. I'm almost a full turn out on 2, 3, & 4. about 7 adjustments so far. Also, my mixture screw is 5/32's from teh carb body top. If I come out more, obviously it will be a smaller measurement. Point is, I'm no where near 9/32 like Rick mentions. Hitachi's, 2.5 turns out after rebuild.

 

Get the Bike running with as little opening of the Throttle Plates as possible.

If the Bike is actually running with the Throttle Plates opening ... the Mixture will be in Transition ... pulling Main FUEL and won't show you a BLUE Window because the Mixture IS RICH.

On the XJ-Bikes ... AIR sneaks IN at the JOINT where the Back of the Manifold attached to the Head.

The OEM O-rings deteriorate and allow air to "Sneak-In" under increased Manifold Vacuum.

This Leak must be sealed by using a sealant and running a bead all around the Manifold where is meets the Head.
The Cap Screws are likely to be seized making the O-ring replacement moot.

 

I understand the air leak thing but the above isn't clear enough for me probably cause I'm stupid.

So I'm all the way at 3.5 turns out and the plugs still seem to be white. I'll post pics shortly

 

the bike is running well. the left pops a little, I had the popping gone at one point during the mixture scew adjusting but it's back. acceleration is a little choppy, very little, but I think I should get the plugs brown first before worrying about that stuff. I have a feeling you guys are going to tell me to get a bigger jet(s). Since I don't know the history of the motor I guess it could have been bored out and never re-jetted. pics of the plug will be here real soon

 

the plugs

 

what a joke. Now I lost cyl's 3 & 4 out of no where. Can't give any throttle input, I could hold the throttle wide open and it just sputs. When I pull the wires on 3 or 4 there's no change and the engine will run with either plug removed. out of no where, all of a sudden, unexpected, not supposed to happen, kapuT, not firing, DOESN'T WORK. I see all the stories about pulling the carbs alot, this will be my 20th time and I don't even know what the last 5 or 10 times have been for! by the way, I've had the petcock in the Prime position for a fews days and no leaks! fuel level fuel level fuel level.