no fire on cylinder 1 xj550

Hey guys, im new on this forum. I just aquired a 82 maxim 550. The plan was to buy it as a bobber project, and right now the only actuall engine modifications is pod filters and straight exhaust. The problem i seem to be having with it now is that it just doesnt want to fire on cylinder 1 ( exhaust is cooler on that cylinder and it runs slugish and sputters when opened up. Every so often the carburator on that cylinder will leak fuel out the intake if i leave the fuel turned on. Iv been through the carbs several times and cant seem to see what the issue could be.. Also installed new plugs, and there is spark on the cylinder that wont fire. Any ideas??? Thanks a bunch! Lots of good info on this site.

 

this is how to test ignition system, when you test the secondary of the coils unscrew spark plug caps (boots) test the ohms should be 10 k ohms . then cut back the spark plug wires 1/4 inch to give better connection to the plug caps when you screw them back on, use a little silicon on the wires insulation to help them slide back into the caps.

 

is your petcock not original if it is its vacuum operated and has no off position. oem has on res(erve0 and pri(me) if not original is the vacuum port capped at the intake carb boot?
sounds like you have a sticking float or bad float valve in carb 1.
what do you mean by Ive been through the carbs? read this link http://www.xjbikes.com/forums/threads/in-the-church-of-clean.14692/
this link will help you understand the circuits in the carb, enrichment (choke) pilot, and main jet.
http://www.xjbikes.com/forums/threads/in-the-church-of-clean.14692/.
this is how to rebuild
http://www.mtsac.edu/~cliff/storage/gs/Mikuni_BS-CV_Carburetor_Rebuild_Tutorial.pdf
you should start by doing a compression test then check your valve clearances to evaluate the engine. instructions are in the info overload link.
then its carb rebuild time to get them zestfully clean.
and of course information overload
http://www.xjbikes.com/forums/threads/the-information-overload-hour.27544/
a lot of reading but you will only get out of your bike what you put into it.
this is a wiring diagram for 550 seca it is similar to maxim excapt for fuel guage and a few other guages
http://frankjohansson.com/stuff/xj550/XJ550ElectricalDiagram.html

 

Try a new plug.....

Still gotta address the leaky float though--- but it COULD be a loose fuel line, or worn fuel rail O-ring, or bowl gasket, or loose bowl, loose drain screw, bad drain screw O-ring........

 

it is always best to look for the simple things first fuel line and clamp whould be the start​

 

thanks for the ideas guys, last night i pull the bowl off the leaking carb, and if i push the float up with my finger when the gas is turned on, the fuel flow stops completely, and when i let the pressure off, it continues to flow as it should. Iv meticulously cleaned the needle and seat and it doesn't seem to stick at all, but when i get every thing buttoned back up together it still will over fuel the odd time. when i pulled the plug ( only a couple days old ) it was covered in soot, i cleaned it the best i could and it seemed to be sparking good, but who knows, maybe that's my issue..

 

If its got a good spark, it probably ain't the plug.

Using your finger on the float is no indication--- you're finger is a lot stronger thang the float itself. But that being said, my thought would be to replace the whole fuel valve assembly..... Better yet, do all four, do your wet-setting and be done with it.

 

some times when you first fill the bowl with fuel you have to tap on the bowl with a screwdriver handle, i belive it is due to the inrush of fuel and escaping air causing the floats not to float properly , i adjusted the other Tang the one at the float and post which sets the low end that the float can drop when bowl is empty.
you could try turning the prime on and off several times to slow the flow of fuel into the bowl when first filling.

so is your petcock standard issue vacuum controled?
did you ohm out your ignition system? to eliminate it as a pronblem
sooty plug is a rich plug (extra fuel less air)
in the information overload thread it explains what could cause sooty plugs.
you could try taking a spare spark plug connecting it to cylinder 1 plug wire ground it to head and see if you have spark when you turn it over.
if you have spark you will have to look at other things
warm up the engine put a new plug in and run the bike at idle for 5 minutes then look at plug. sooty? this is called a plug chop.
typicaly with pods and open exhaust you run lean did you check your jet size po could have over jetted it to compensate for the mods.

do the testing of ignition and plug chop at idle and get back to us.

 

Normally you don't need to do anything with the float low-stop tang. If it got bent,then yeah...... Otherwise leave it alone. If the fuel level drops, the float automatically drops. THAT tang should not be holding the floats up, rather, it just keeps floats from dropping too far and risk having the fuel needle slip out

 

well it turns out that it was just the spark plug. I tossed a new plug in and did a plug chop, the new plug looked good after i pulled it out and inspected it. I guess the old/new plug just had too much soot on it to properly operate.

the other issue i have with the bike now is, the clutch seems to be slipping a little when i crack it open. The clutch plates are new from the previous owner, however when my one carb was over fueling it dumped a significant amount of fuel into the engine. i changed the oil the other day with proper motorcycle wet clutch oil but it still seems to be slipping.. could there still be enough fuel residue inside the engine to thin the oil enough to cause slippage? When i dumped the oil, i also cleaned out the oil filter with fresh oil.

 

Adjust your clutch cable. Gas contaminated oil won't make the clutch slip. Just because the PO says things are new, does not mean that those thigs are new.

 

ok, ya its even adjusted to the point where I have a harder time getting it into neutral.. iv taken the clutch apart already and the clutch plates appeared to be new.

 

How many km on it when you bought it?

 

Ooooh, kms... K-moe goes international!
kms...K-moe... coincidence? Or undercover Canadian?

 

Roughly 25,000 kms. Seemed kinda low for the year. Where can i find a rebuild kit for my carbs? Im thinking if i want it to run right, i should probably rebuild them.

 

Chacal's got it all., knowledge, great service and almost every part for all XJs. Link to Xj4ever is at the top of the page. Or start a conversation with him. He'll hook you up.
Or here's a shop in Ontario...
http://m.siriusconinc.com/index.php
Don't see complete 4 carb kits, but I thought I saw individual ones. I was searching 750s though, didn't check 550s.

 

awesome, good to know! another question, sorry this is kind of amateur, but can floats that are not set the same or at the right level cause cylinders to run either to lean or rich, causing misfiring or even no firing?

 

Yeah, float height is an important part of tuning these carbs. Too low can mean lean, or in extreme cases, fuel starvation... just not enough gas to feed the machine. Too high will cause the opposite. That's why the XJ masters stress the bench float set as a starting point, as well as the wet set (on the bike) to get it dialed in.

 

Science!

 

That's low enough miles that the fiber plates could be hardened from sitting, which will cause the clutch to slip. Even if they look new the plates may be the originals.

 

So I did a compression test, and the results came in at 125 psi on cylinder 1, 93 psi cylinder 2, 105 psi cylinder 3, 140 psi cylinder 4.
it seems pretty weird there is a almost 50psi difference between my cylinders, however when I tested I left all plugs in the engine, and never held the throttle open, plug caps were off though. So, would my next step be to do a valve check/adjustment and then redo the pressure test? If so, how do you do a valve adjustment on these engines?

thanks

 

im thinking that possibly the difference in cylinder pressure is causing my misfire..

 

http://www.xjbikes.com/forums/posts/122016/

 

you should unplug the tci when doing the compression test also throttle wide open remove air filter
550 engines:
Minimum: 100 psi
Standard: 121 psi
Maximum: 135 psi
Max. variance between lowest and highest: 14 psi
READ how to do the test PROPERLY
http://www.xjbikes.com/forums/threads/the-information-overload-hour.27544/
it is very close to the top of the page
you have to do it right to do it right.
retest so you have the correct info to compare to when you change your shims.

 

So my engine is running better now that i adjusted my floats and synced the carbs. However it is still running rich on two cylinders, and im thinking its maybe my emulsion tubes that ate plugged... Now the isue is getting them out with out destroying the carb body. From what i can see the push from the bottom up into the carb body. They are so coroded they just will not come loose even after using a large hammer and a socket that fits the tube right... Any ideas on what to do?

 

do not use a socket use a dowel . the jet holds them in place . you remove the slide
if you look at the naked carb photos
http://www.xj4ever.com/inside your carbs.pdf

page 22 you will see how things flow into the carb you want to squitr carb cleaner into the air jet on the right side of the carb rear of carb the cleaner will flow down to the emulstion tube it should come out the main jet hole. also if you squirt it in where the slide needle it will come out the main jet hole.

tape or plug the main jet with something and fill up the holes with cleaner and let it soak in then remove main jet and try tapping it out from below

edited out removed direction someone slap me .

 

XJ550H
Hold up a sec here, look at page 24 of inside your carbs.pdf. You will clearly see that the brass emulsion tube is machined on the slide (upper) side of it with a shoulder and must be driven up from the bowl side once the jet and copper washer removed. Unless I am missing something here the jet and copper washer hold that emulsion tube in place from the bottom side and would have to be driven out going up.

You may want to revise your statement "THEY SLIDE OUT INTO THE BOWL SIDE NOT UP"
Please correct me if I am wrong

 

Unscrew the main jet from the bottom making sure you get the washer out as well, and then tap the emulsion tube up into the carb throat:

 

you are correct

 

So I guess I never realized that there is a washer sitting on the tube under the jet "smacks head" im lucky I never cracked the carb body heating it up and pounding on it.. How do you get the washer out? can you just pick it out fairly easily?

 

After the jet is unscrewed, the washer lifts right off. It may be gummed, but a small pick or screwdriver carefully used will lift it.

 

Haha! Yeah, after you said you had a socket that fit the tube right I was wondering if you knew there was a washer there. I was picturing you pounding on the washer wondering why the emulsion tube wouldn't come out. That's why I specifically mentioned the washer.

Glad you didn't crack anything!

 

No worries
Just didn't know if something was different with Mikuni 550 carbs. I know I had some apart years ago. Thought they were the same as the Hatichi's I'm always messing with.

 

Well they were pretty much plugged solid through all the little air holes. Now that there cleaned and back in the bike she's a whole new beast should it still pull hard past 130 kms in 6th gear. It seems to go like a scared rabbit up to about that speed...

 

Excellent. Now that you've got the emulsion tubes cleaned out, check your plugs in a little bit to see what they look like.

 

So my plugs look great, and the bike runs good with plenty of power, the only thing is it seems to have very poor top end power, the fastest i can get it to go is 132 kms/ 82 miles per hour.. And by the sounds of it this bike should do at least 100 mph. Because im running straight exhaust with no bafffles could this effect the top end power. Up to that speed it pulls really hard. Any help would be appriciated

 

Yes.

 

Rice_Burnarr........nice picture!

 

I don't ride fast so I'm not the best source to provide input into your high(er) speed question, but I did recently approach the speed you mentioned and at that point my bike felt like it had plenty more where that came from.

So I'm no expert on high speed operation, but in addition to the potential tuning issues caused by the pods and straight exhaust, I would consider fuel sources to rule out high load fuel starvation issues. Float bowl levels, dirty float valve beanie filter screens, dirty and potentially clogged petcock, carb bowl gaskets, and maybe even a partially clogged gas cap vent. That kind of stuff can go unnoticed because it doesn't have impact under low load, low fuel consumption conditions. But under high speed, high fuel consumption conditions, you may be (temporarily) running out of fuel.

You might be able to test for tuning issues by adding a little choke when you've topped out. If your bowls are full, you should be able to introduce additional fuel to the mix by giving it some choke. If choke helps at high load, you're probably looking at a tuning issue. However, if choke doesn't help, it might be because your bowls have been sucked dry due to the load and there's no additional fuel to add even with the choke. Although it might depend on how low the level is... The choke pickup might be lower than the main jet.

 

Haha! Thanks! Couldn't have done it without you.

 

ok, so im still baffled with my lack of power at wot. I built lollipop baffles for the exhaust, thinking it was a back pressure issue and it actually ended up decreasing the top end power even more.. It seems like if it was a getting under fueled it would sputter and miss somewhat. Could it be that I over jetted it? it comes stock with 112 mains and I installed 117.5 mains, and keep in mind that its got pod filters and straight exhaust. Also could it be the needle setting? im not really too familiar with how to adjust the needle and exactly what it does.. sorry, I seem to be beating a dead horse, I just want this bike to run to its full potential.
thanks guys

 

Did you try giving it a little choke after you had topped out?

 

I'm not seeing it anywhere in the discussion....

Have you actually checked and adjusted your shim clearances yet?

 

Iv tried giving it choke and it doesnt help the power at all.. No i havent checked the valve shim clearences, where would one obtain new shims if it apears to be out of spec?

 

Some dude named Dave runs a shim pool. If only there was a way to draw his attention to this thread... @hogfiddles , do you know how to get a hold of him?
Getting the shims into spec is an extremely important step to getting these bikes working properly. Check this link:
http://www.xjbikes.com/forums/threads/airhead-valve-adjustment-with-pics.14827/#post-122016

 

Also i was just riding today, and it felt like the clutch slipped out through 4th and 5th. It has new clutch plates, but iv been having issues getting the clutch adjusted proporly. It seems when it is set right, it wont go into neutral, and if its set so that it can go into neutral then it noticeably slips under hardly any load. Maybe it needs a new cable.. But could that be whats causing the power loss?

 

Cool, that would be nice. Lol iv been kind of avoiding doing the valve job due to the fact it looks like a good size job

 

what oil are you using? oil not specifically designed for wet clutch motorcycles (or deisel engines, for some reason) will make your clutch slip. Check out K-moe's oil link:
http://www.xjbikes.com/forums/threa...or-a-wet-clutch-motorcycle.43702/#post-386713
As for the valve job, it's not thaaaaat tricky, once you've got the tools and info. It gets easier each time as you become more familiar. If you don't want to buy the shim tool, read this too:
http://www.xjbikes.com/forums/threa...-the-tool-vs-ziptie-w-pics.29209/#post-249951
Listen to BigFitz. He the man.

 

So choke didn't help at WOT. Implication is that either A) you are already giving it more fuel than it wants, or B) that your fuel bowls are being sucked dry and there simply isn't any fuel in the bowls to be added by the choke.

Sure would be nice to know if it wants more fuel or less fuel.

If you've got a working vacuum petcock, you could do a WOT chop to see what the bowl level is. Run at WOT until it won't go no more and then kill the motor and coast to a stop. Then once you're stopped, check the bowl levels. If the bowl levels are way down, you're sucking the bowls dry faster than the supply can refill them.

Maybe some of the smart guys around here can come up with an easier way to figure that out...

 

Stop chasing your tail.
Read this: http://www.xjbikes.com/forums/index.php?threads/the-information-overload-hour.27544/
Do all of the things.
Nothing can be avoided. Everyone who owned the bike before you avoided the maintenance; you can't afford to.