NOT STARTING...PLEASE ADVISE!

I just inherited my dad's '82 xj650j, which i rode for years, after he gave up on it because it wouldn't idle. I thought it might be a vacuum leak caused by cracked carb boots. Replaced them and rebuilt carbs. Nothing! After 15 minutes of starting, holding the throttle wide open and choking it to keep it running suddenly something clicked and it ran like a dream. But once it cooled down after the ride it wouldn't start again. I noticed a sheared off screw, one of four which holds the #2 carb hat on, replaced it...no help! I cleaned and checked each diaphram and needle set too but she still won't fire up. It smells like gas and some dripped out of the air intake boot for #2 carb. Where should i go from here guys?

 

Check float levels. Floats apparently easy to install upside down. Carbs sound like they need bench synch first. Replace air filter. Check petcock to be sure it is OFF when in "ON" and motor not running.

 

Have you got a good healthy spark on all 4?

 

I still have to do a good check of each spark plug. I pulled out one and checked for spark and it didn't seem super-bright but there was a spark. But it's also hard to make a good contact on a bare engine surface since it's painted. Do you have any suggestions for a better way to check for healthy spark? My checklist has "assess the spark plugs and boots" so maybe i'll do that next.

 

I just had my carbs rebuilt by a 30 year yahama master mechanic, it idled perfectly but ran like chipmonk choking on walnut, now, it idels perfectly and runs like a banshee, he told me that there are several circuts in the
fuel path in those carbs that kick in at different times, and some toghether at times, he
said that your problem is the carbs were not correctly rebuilt, that sometimes you CAN NOT reuse the same parts as they were bad to begin
with from the factory and grew out of tolerance with use, he says you need a professional to rebuild them so that problems an ameture would
not catch can be found and corrected, no insulte to your work intended, but
some carb sets are as he stated " carbs from hell " and no one but a master rebuilder can fix them right....

So, hit up wild george , or some other carb pro here, have them fix them right ... my complete rebuild only cost $125 u.s. took 2 days,... was
WELL WORTH THE MONEY.

 

Hi asphaltgecko, beware of the sales pitch, there is nothing in the carbs that needs a master mechanic. With the help of XJ BIKES anyone can achieve top results. Wiz.

 

My '83 ABSOLUTELY WOULD NOT start earlier this fall. Fully charged battery, new air filter, inline fuel filter, fresh gas, petcock on PRI, ran when I parked it. Spark but "watery." Took the '81 to AutoZone and got a BRAND NEW set of plugs. Gapped, dab of antisieze, installed and torqued, and it fired as soon as I TOUCHED the damn button. The old plugs LOOK fine. They came in the bike. Original? Maybe. Bad? yep. And Wiz is right, these things (CV carbs) aren't rocket science. You just have to be careful and meticulous (or just downright anal.) They are Voodoo however.

 

plugs often will break internally and with heat they will "reconnect". it happens often on our race machines. plugs are cheap and easy to replace, good place to start would be to check for spark when its not starting.

 

Thanks Zookie400! I called my Dad last night (the PO) and he said, "Come to think of it after i changed out a bad spark plug cap i think that's when all of my problems started." If one was bad, i'm sure the rest are hanging on for dear life too! Tonight I'm going through the plugs, wires, caps and petcock and tank if i get to it. Someone said these tanks are notorious for rust in the corners and quirky petcock issues. I'll let you know how it goes!

 

I checked each spark plug, cap and wire and they look good and are each sparking. After trying to start the bike for several minutes, i took out the spark plugs to check them and the #1 plug was dry, #2 had a small amount of gas, #3 was soaked with gas/oil as was #4. Next i took off the carbs to check the floats since #2 carb was still leaking gas out the intake boot and i had a hunch there was a fuel distribution problem. I popped off the bowls and #1 float was 80% dry, #2 float was 95% dry and #'s 3 and 4 floats were each 50% (which seemed like a normal fill level). I pulled out #2 float and float needle and there was a piece of something in the float needle seat which i removed. I left the bowls off, hooked up the gas tank to the carbs on my work bench in a pan, and set it to prime to check for fuel distribution to the bowls thinking that they weren't getting fuel equally. A healthy supply of fuel flowed out of each float needle and the floats were each set the same to shut it off. What should my next step be?

 

Since you have ignition, spark, and the plugs are working I'd start looking at Float Settings and do a live test of fluid levels.

Get small diameter clear plastic tubes of equal length, 8-10", insert a tube into each carb's bottom bleed hole. Tape loose ends up to the carb tops. Study the photo.

Place carb rack in a vise evenly; fore / aft / side to side. Use a small carpenter's level to check that the set is even. Level goes on top of the whole rack across the tops.

I used a turkey baster and paint thinner to fill the carb set from the center T or main fuel line. Why thinner? because it's safer than gas or water.

After you have the set filled up go down the line unscrewing each bleed screw until fluid starts to rise in that bowl's tube. The fluid level should rise & stop, then you turn it off & go to the next carb. You may have to add fluid at the T or swivel.

If the floats are set and working properly at 21.5 mm each bowl's fluid fill should be level with the heads of the bowl attachments screws +/- 1 mm. All bowl tubes should have the same fluid level evenly across the set. See the pic below. Remember to drain the thinner out and close the bleed screws.




Bench Sync:

Next stop - examine your carb set's butterfly valves. Are they almost closed evenly in the venturis? If not back off the small spring-loaded rack throttle adjust screws until they all closed. The large idle speed adjust screw on the bottom will open them enough for starting.

Leaking Manifolds:

Check the 4 rubber carb manifolds carefully. Are they old, cracked, dry & possibly leaking? If so; its time to either fix them or install a new Carb Holder set.

Check & Recheck:

Check everything in the fuel system very carefully. Make sure the tiny inlet valve clips go over the float's center tongue / tab or it won't operate properly. Are the idle enrichment jets clean and flowing in the bottom of the bowls? I had to replace a Float Inlet Valve that looked good but it leaked anyway. Keep after it ... it will start.

 

While you're messing with the carbs (all of the above is sound advice but the bench synch is a bit more complicated than that) be sure they all pass the "clunk" test. While it won't contribute to starting issues, you don't want to have to pull them again when it refuses to idle back down.

 

Here's the Bench Synch quote from Chacal's recent reply to: "leaking carb after #3 / #4 rebuild"


"CARB" SYNCHING AND OTHER FANCIFUL MYTHS:

Q: I know that you adjust the valves first (valve cover gasket also on the next order) but what is the sequence for the Colortune and Carbtune?

A: Well, it depends on whether you've "rebuilt" the carbs or not....kinda depends. If you've had the carbs off the bike, then the first step is to "bench synch" them, which means getting the butterflies "pretty close" to being all equal in terms of how much they are open at their fully closed (idle) position

"(the butterflies never actually "fully, completely" closed, they always remain open a tiny amount, otherwise the bike wouldn't get any fuel-air mixture in, and thus wouldn't run).

"Synching" on a bench means adjusting the synch screws (there's only three of them, the #3 carb doesn't have one because all of the other carbs are synched in relation to #3) while eyeballing the other throttle butterflies, and getting them "close enough" to allow the engine to start and run."

ACTUAL HOW-TO DO BUTTERFLIES:

PostPosted: Mon Jun 16, 2008 6:57 pm
Post subject: Re: Bench Sync Carbs
Your carbs are off the bike and on a table or bench?

Your #3 carb is controlled by the knob under the carb. You want to close this butterfly onto an object. (paper clip, 1/4 " strip of business card, the wire inside a bread wrapper tie)

With this object trapped in #3, you then shut another butterfly on another carb on another identical object, doing #1 last because #1 "leans" against #2.

When you have everything adjusted just right, a slight turn of the idle knob will allow you to drag these 4 objects out with the same resistance "feel". All 4 butterflies are opened the same amount.

Then, when you get the bike running, you have to sync all over again !!!
even if you get the bench sync perfect. Search topic- - manometer- - carb sync- - plug read- - bench sync

In the pic I used 4 business card slips - they are under 1mm in thickness. Adjust all 3 throttle screws so the slips can be eased out. You may have to "pre-load" the throttle by turning the large Idle Speed Screw IN until it just barely begins to open the butterflies. You can always back it off once the engine is running.

 

Happy Turkey Day,

Thanks to all for the wonderful suggestions. I will be following them to the T, after the carbs are put back together after cleaning them The Whole Nine Yards. A special thanks to Rick for that awesome tutorial!

I will be sure to post my progress as I continue to go. For those who haven't followed RickCoMatics "Clean Your Carbs- The Whole Nine Yards" tutorial, I implore you to read it and follow it. The olive oil and Propane Torch technique worked wonders on a buggered and rusted pilot screw!

Today I'm thankful for XJBikes.com!

Chris

 

Hey Guys,

I just installed a fresh battery which was fully charged. After 10 minutes of kicking over and spraying carb cleaner into it, the bike started - revved high - and died. This happened numerous times until I stopped using carb cleaner, now "nothing" when it kicks over. Bike was fully choked getting plenty of flowing fuel and each spark plug is sparking. For those who are new to my situation, I have already cleaned carbs, clunk-tested and bench-synched.

What else am I missing?

 

Got the throttle & choke cables switched ?

 

How do your throttle shaft seals look? Any chance they could be contributing?

 

Wizard- I thought about the throttle and choke cables being switched but they were fitted back correctly.

Joe- I know the throttle seals should be changed in the near future, but I don't see them as the problem. The bike was running in January and the idle was nice and steady. Unless the seals cracked over the last few months which could be possible.

I had hoped there was something I could check before ordering more parts. Any other ideas?

Thanks guys!

 

Hey Guys,

I just installed a fresh battery which was fully charged. After 10 minutes of kicking over and spraying carb cleaner into it, the bike started - revved high - and died. This happened numerous times until I stopped using carb cleaner, now "nothing" when it kicks over. Bike was fully choked getting plenty of flowing fuel and each spark plug is sparking. For those who are new to my situation, I have already cleaned carbs, clunk-tested and bench-synched.

What else am I missing?

Please help me guys! I wanna ride again.

 

It sounds like you are not geting fuel.
It revs high until the carb cleaner runs out, then dies.
Could be a petcock issue.
You could pull the fuel line turn it over see if you are getting fuel when the bike is turning over.
It will pour right out.
Do you have an inline filter that may be clogged?
Easy things to look at.

 

Thanks Hound. I had the petcock apart and it was pristine. Inline filter was pumping gas through no problem.

Thinking out loud here: I'm suspecting fouled plugs maybe. I have yet to change them.

Could my plugs be fouled also because of too much Seafoam to gas mixture and attribute to a rough running bike? Would this cause the bike to spike a high rpm then die suddenly.

 

clean your plugs... but more importantly did you ever do a good thorough cleaning of the carb? also in your inline filter is it catching alot of material? pull your carbs again and check each and every passage in the carb to make sure it passes cleaner through it.... dont skip your fuel, idle fuel circut or anything. you may have to pull your mix screws as well .... best to tear it completley down and start from scratch. you definatley have a fuel delivery issue on every one of your carbs treat it as though they are all bad and most importantly learn the steps -

- i have been subject to my own wisdom manny times
"Do it right or do it twice"

 

Pull the plugs and look at them.
If they're black and sooty replace them.
Cheap enough, just remember they got that way 'cause something was wrong.

 

Doesn't this issue still seem like a fuel issue? It runs as long as he sprays carb cleaner into it it runs. Stops spraying carb cleaner it dies. The question is will carb cleaner burn when gasoline won't? I'm pretty sure ether will burn where gasoline won't but I do not know about carb cleaner. If he opens up the drains on the carbs there should be gasoline in them. If not then suspect petcock, check by disconnecting gas line and setting petcock on "prime" position at which point gas should pour out like the dickens, or it's likely the filter as TheHound suggested above.

When I first got my XJ i didn't know about this forum. The bike had been sitting for over a year, the float bowls were dry, and I didn't know about the prime position on the petcock. I used ether to get it to start and by spraying ether in the airbox for a while vacuum eventually opened up the petcock and filled the float bowls at which time it ran on gasoline. Not well but it did run. This was encouraging enough to pull the carbs and do a "best able" job cleaning the carbs. It does well up to 6000 rpm at which point it runs erratically. A good "by the gurus" carb clean will fix this issue once and for all.

Still think it's fuel or carbs. Hope I'm right. The repair is a time consuming pain but it is cheap!

Wamaxim

 

what /\ he said

 

Hound! What are you doing up this time of night? I have an excuse I'm working! I guess it's 5:30 a.m. for you but man that's still early!

Wamaxim

 

we dont need excuses ... we are XJ addicts

 

Amen bruddah

 

Ok... I pulled carbs off (as advised) and here is what I found after removing the bowls.

 

Once I got them completely dismantled I found the real culprit. GUNKED UP EMULSION TUBES! I didn't think to clean them out like a rifled gun barrel! The last time I had these babies apart, I soaked the tubes in carb cleaner and made sure the holes were all clear. But that is where my cleaning stopped! And once the carbs were back on the bike and it fired up, all the gunk from inside the emulsion tubes was jarred loose and contaminated the entire carb system like a virus. This junk was everywhere!

Let this be a lesson to all! Clean everything thoroughly!

 

yup you are getting fuel hence the rust. you will want to add an inline filter if you havnt done so yet. find one that is perfectly clear so you can see when its clogged up. you need to clean your enrichment circut, pilot jet, Etc look in my gallery or in the manual there is a good diagram of how the fuel circut operates. you will need to pull your mix screws and clean top down and from the bottom up. I always listem and watch the flow of cleaner for pitch changes when cleaning. when clean that all sound exactly the same when shooting cleaner through or compressed air. if they dont sound exactly the same on each circut it isnt clean yet. you'll understand after a good cleaning why its not working now. also double check your intake gaskets & boots while your there you dont want to have to go back if you can avoid it.

 

Oh there is definitely fuel flowing into the carbs and I've added an inline fuel filter to catch any debris from my tank cleaning process. The sediment/rust you're seeing in the bowl is from the inside of the emulsion tubes that I forget to dislodge during the last "Whole Nine Yards" cleaning. Apparently I only cleaned them "Seven" or so yards!

Thanks Midnight, I'll check in your gallery for the pics! The enrichment circuits, pilot jets, etc. were cleaned before. The only things I haven't touched, that I know of, are the butterfly seals. I have a feeling this is not the last time these carbs will be apart for a cleaning though... and that's ok. I'm getting more familiar with them.

 

Butterfly seals were indeed in sorry shape! I think I was just not confident in my mechanical ability to break the rack to get to them. However once I started dismantling them (After taking lots of pics and video) it wasn't that bad! There really wasn't that many parts, just document the way the springs are loaded onto the valve shaft and you're golden.

Now... waiting on my new seals and it's back together with you carbs!

 

Another Before cleaning shot!

 

Here is the current state of my xj650j! I can't wait to get her up and running again.

 

Wow those are some shot seals. you will be surprised how well she runs once you get the tuning done. Nice looking carbs cleaned up - great job.

 

Holly crap!
What burned on top of those carbs. 8O
It looks like my drunken friends were BarBecuing on them.

 

I smell PROGRESS! Good going, Palmer. Bike sure wasn't going to run right with those butterfly shaft seals, and you're going to have the valve train dialed in. Boy will you be surprised.

 

Hey guys! I realize I haven't given an update in a while so I wanted to follow up on my findings for those who have read this thread and are having similiar start-up problems.

RECAP: The picture you see in one of my last posts above; the one that looks like the carbs have been burnt to a crisp is the carb rack before it's cleaning. I've since stripped the old black paint off and polished the bodies. The odd texture on the carb hats is pitting from rust that was painted over.

NOW they've all been boiled in Lemon Juice (about 1.5 hrs per carb), polished with 1000 grit sand paper, and cleaned thoroughly with Q-tips and wire brushes, cloth, etc. The boiling worked great and the dirt/old paint/ rust just wiped right off. The butterfly shaft seals and shims have been replaced and put back in working order. Those stinkin emulsion tubes have now been polished inside and out. The dirt trapped inside the tubes was adding to my NOT Starting issues.

IT NOW STARTS...BUT WHY?

BECAUSE #1: The carbs had a good cleaning- The sediment clogging up the circuits was a factor!

BECAUSE #2: The plugs were too sooty- Not enough spark!

BECAUSE #3: The battery wasn't good enough- It should've been pulling over 12 volts but couldn't so I replaced it.

BECAUSE #4: I didn't have a good flow of fuel from the petcock to the carbs. My fuel line was bent funky and the inline filter was too large (It was the smallest car fuel filter from Walmart I think) so the fuel flow wasn't flowing fast enough!! More like a slow trickle!

And BECAUSE #5: I didn't have a clean enrichment circuit- If you haven't performed this operation that sprays carb cleaner into your eyes PLEASE do a search for it.

I think that replacing the butterfly seals and shimming the valves helped it's performance, but wasn't the reason it wouldn't kick over. The butterfly leak was so minuscule that it just added to all of the above things that were wrong.

Here is a pic of my bike after a long ride which revealed my plugs are blistering white and my pilot fuel circuit isn't working. No turning of any kind will get the mixtures rich or color on my plugs. Either that or my #40 pilot fuel jet is too small to compensate for the massive #118 main jet. That's where I am at the moment!

 

Thats a very interesting point. Ive only just got my XJ and it was running a bit dog when I got it. Ive been tinkering a little and managed to get it running something like. However, on the way home from work it started mis-firing a bit and I needed to apply the choke to keep it running as it wouldnt tickover very well, and at low revs the clutch was making a hell of a racket!

Ive just taken my tank off to check my carbs again, and I have realised that my petrol cock only lets petrol flood out when it is pointing towards the rear of the bike, with the word "fuel" uppermost. I cannot get any fuel to come out when the tap is pointing downwards or forwards however the filter is full, and I thought the bike had to have the tap pointing downwards for normal fuel and the tap in the rear facing direction is the reserve. Could this be my trouble? Have I been running the bike only on fumes? Am I an idiot, or do I have other problems?

Thanks

 

Could be a vacuum leak between the carb and the petcock (change that line or test by applying vacuum to the line and seeing if fuel flows freely in the normal (down) position). If you can't get fuel to flow that way, perhaps a clean/rebuild of the petcock is in order.

 

The petcock is vacuum operated. You should have a fuel line and a vacuum line to it. To teh rear is Prime and will flow fuel no matter what. Straight down is ON and will flow when engine is running only due to the vacuum operation. TO the front is reserve. Same as on in operation

 

Thank you very much for the info.

With your help I managed to find what my problem was; the vacuum tube was perished and wasn't making a good seal at all. I put a new piece on and she fired up straight away, smooth as a nut !

Ive also put some Putolene fuel treatment in to clean the fuel system and she seems to have settled down a little and the tickover is a little more smooth.

Happy days, thanks again for the help. Brilliant forum bye the way, I think I will stick around a bit...

 

Hey! I finally got one first!

Only repays the 50 or so other have given me!

 

Hi you all!

I had similar problems with my 82 750 seca.
Just renewed float jet needles and checked float levels also.
That did work perfectly.

Before that the fuelconsumption was like 3 gal per 100 miles and that sparkplug dealer nearby bought a nice sailing boat afterwards :lol: :lol: :lol:

 

Hello Gentlemens,

I unfortunately have to ask for help for the first time with similar non-starting issues as Palmer, hence I didn't start a new thread.

Here's my situation,
I've had the odd immensley loud back-fire bangs known to mankind but that's it.
Petcock is not suspect and flowing fuel, it's new
Carbs have been clean multiple times and are definitely not dirty.
In detail:
float needles replaced
needle jets cleaned and at spec
jet needles are straight and true
all circuits have been cleaned thoroughly
main and pilot jets are new as I have a four into one pipe on
126 and 41's respectively
machine was running prior to carbs being off
three turns out on a/f screws
float levels are good and I have gas in the bowls
I have excellent spark with new iridium plugs on all cylinders
Gas in new also
No holes in intake boots either side
I've even plugged air inlets to induce a false vacuum and to that I get a little fuel coming in but not nearly enough. I'm beginning to wonder if I've left a cloth in place before stuffing the carbs back on.

Despite turning over LOTS, nothing, there must be some 1/2 inch alien monsters that don't grow and live solely on vacuum and fuel living in my intake tract as each time I pull a plug, they are completely dry! If I could just get the air and fuel to take that four to six inch trip down the intake tract, I'd be in business, I think, God save me from any other unforseen crap!

Thanks for any help anyone might offer

 

Do you have a prime on your petcock?

 

Yes, and it works. however, same response with petcock in "pri" position as in "on" position.

Btw, I'm not aware of XJ1100 only the xs1100, what does the xj1100 look like?

Nevermind, did a google. learn something new everyday, I didn't know there was a Maxim 1100. Cool!

 

Hey, I am new to motorcycles and I recently got a 1985 Yamaha Maxim XJ700X. It isn't getting any spark to any cylinder. I checked coils and I got 3.8 Ohms, then I check the pickup coil and I got 238 Ohms for one and 128 for the other. I am using a Harbor Freight Multimeter so it's not the best, not sure how I much I can truck those numbers. Any suggestions what to check, or what to do. I don't know much about Motorcycles I am usually a car guy, this bike is my first attempt in the adventure.

-Craig

 

Usually means something is not right with the Safety Switches.

Try:
Removing the seat.
Looking for the RELAY beneath the Tank.
Un-Plug.
Bike in Neutral.
Try it.
Varoooom? Safety Switch (Kickstand, Clutch Lever, Neutral Switch)
Need troubleshooting.

No Varoooom? Ignition related.