Cylinder not firing troubleshooting....please help

[rich_mcd]

My experience so far.
I bought an '80 xs last year, didnt do to much to it, this year I am trying to get it on the road. I have recently put the keihin carb kit on, with straight pipes and the bikes starts up and fires almost everytime with the first kick. The kick is pretty hard, so I assumed compression was pretty good.

The issue I have been having is the right cylinder seems to not be firing. This is what I am assuming due to my incredibly little amount of mechanical experience. The pipes shake, and push out air and get hot, but the plug seems to be wet with either oil or oil/gas possibly. I get a spark from both plugs, but I don't know what defines a "good spark" so I just assumed it was good enough, switched the wires to the plugs, little to no change.

Unfortunately, the bike got rained on last night, but it doesn't seem like any water got into the carbs just the outside of the pods are wet but now when it is running it pops blue smoke out the carbs.

I am going to do a compression test now, and adjust the cam tensioner but I was curious where the TCI is so I can disconnect it for doing the compression test. Also, how to I check the coils with a ohm meter, Like I said, I am an incredible newb!!

Rich

 

[xjwmx]

I had an inlet valve sticking open in one carb. The first symptom was that cyl wouldn't fire. The second symptom was gas pouring all over the floor from out of the airbox. If you have a leaky carb inlet valve it might cause firing on one cyl.

But your pipe gets hot, so it is firing.... If your smoke is dark rather than bluish, it's over rich. Bluish is oil, white is water vapor.

The tci connector is under the left side plastic cover. For testing your coil, there's already a lot written on that.

PS. after you do the cam tensioner, check the valve clearances, esp. the exhaust.

 

[rich_mcd]

I checked my battery today also, I was reading 11.6V with the bike off. Would that result in poor spark and thus poor firing from the cylinder? The left side plug looks great, nice colour and all but the right, not so much.
It almost sounds like gurgling from the right side, and there is a spark....SOOO I am assuming again that maybe it is just weak.

 

[xjwmx]

But what does it read running? Charge it at the 2A setting or less for a couple hours. Then check the voltage at around 3000 rpm and see if you can get it to read between 14-15V. If not, troubleshoot the charging system. 11.6V isn't low enough to make it run bad though, if it reads that while it's running too. Charging is easy to troubleshoot with '80 and up.

 

[weekendrider]

To start you may want to get the pods dried out. You swapped the wires and the problem is the same have you swapped the plugs? Check your plug caps for resistance.
A loose spark is easy to find in the dark. Maybe check the ends of the plug wires and trim if necessary.

 

[rich_mcd]

First off, thanks for all the help and responses so far, I really do appreciate it.

So, I checked the charging system at 3000 rpm, read 14.4ish V. I have the pods off right now, just trying to get the cylinder going, it has been doing this for about a week. I checked the cam tensioner and the little tit, for lack of a better work comes out and goes back in fairly even as I turn the rear wheel with the plugs off.
I am going to check the valves next, but I need to go buy some feelers. How would I go about checking the resistance at the plugs? I have a multi meter but I am a tard when it comes to using it. Set Ohms to 200, ground it and positive into plug wire?
I am just stabbing in the dark here when it come to electrical especially.

 

[rich_mcd]

how do I disable the TCI? Can I just disconnect the battery when doing the compression test?

 

[gggGary]

If you are going to kick it for the compression test just leave the key off. Or put the plugs back in the boots and make sure they are touching metal.

 

[xjwmx]

The tech section lacks a link to a good compression testing thread. It ought to have one. It's simple but there are things you need to do, like hold the throttle open, ground the plugs, continue till the gauge peaks, and such. It's not xs650 specific, but it comes up a lot.

 

[rich_mcd]

so compression test said 150 psi per side after 5 kicks, went to 7 kicks and it just kept going up. Got to about 180. So, compression seems good, charge and battery seem good, brand new out of the box carbs and still wet right hand plug and gurgling out of the right exhaust. With a weak looking spark. Will try to figure out plug wires and maybe the coils. Stupid bike.....this hobby sucks, lol.

 

[xjwmx]

There's just one coil on it. Put the plugs in the opposite cyls and move the wires to the opposite cyls too. Leave the wires the same at the coil. It will run that way if you have stock ignition. See if the problem changes cyls. 180 is crazy high. Could have lots of carbon build-up. Could also have fluid of some kind in it.

 

[mrriggs]

What you are describing sounds exactly like what my bike was doing with the Keihin carbs and drag pipes. It was running so rich that it was fouling the plugs and causing to run on one cylinder.

Everything I did to get these carbs working right is in this thread.

http://www.xs650.com/forum/showthread.php?t=6592

 

[rich_mcd]

Yea its a 650, I was kickin' the hell out of it, 7 kicks, basically got tired so I stopped. Any way to flush the carbon without tearing it apart? Gonna try switching the plugs and wires again tomorrow, and see what happens. As well as checking the valves.

What else could be causing a weak spark? The manual said a check the ignition coil; primary and a secondary, so I assumed there was 2. To check the resistance of the coil I put the positive meter on the plug and ground out the negative? I am looking for 2.5 ohms, so I set the meter to the 200 and look for 2.5 ohms?

 

[crazyazsredneck]

put new plugs in they are cheap and solve alot of common problems ,also brand new carbs are not set , just close enough to get it running . so u can finish the fine tuning and adjustments needed. sounds like one side is to rich adjust ur air to fuel mixture

 

[xjwmx]

The manual said a check the ignition coil; primary and a secondary, so I assumed there was 2. To check the resistance of the coil I put the positive meter on the plug and ground out the negative? I am looking for 2.5 ohms, so I set the meter to the 200 and look for 2.5 ohms?

The sec is where the plug wires come out and the pri is the other two terminals. Two independent coils like a transformer, inside the "coil." If you're getting spark on one side at least, the coil is okay. It's either plugs, wires, or attachments. Very easy to check by switching them around like I said before.

I would pay heed to riggsy on the Keihins, if you're having his problems.

 

[rich_mcd]

It looks like I am going to make up a sync tool, see if maybe the cables are contributing to the problem and order new needles.The left plug was a nice tan colour but has since become dark and covered in soot. So, I will see if I can lean the whole thing out a little before I the new needles get here and see how that goes. Anybody have any ideas where to get needles like this in ontario?

 

[Q Tip]

this may be way out of left field, but are you running vacuum petcocks? On my GS500 Suzuki, I had a torn diaphragm in one of the petcocks. When the bike was running that carb was sucking too much fuel and drowning out the one cylinder. It was intermittent for a while then all the time....I changed the (faulty frame mounted) petcock to one from a Honda 250 dirtbike and the bike has run perfectly for about 8000 miles now.

 

[Gordon]

On the coil, the primary side is the side that has the regular wire's running to the 2 post's. The secondary side is where the plug wire's come out of the coil. Your coil should have 2 plug wire's coming out that can NOT be replaced! However, as was suggested earlier, trim about 1/4 inch off the end where the cap that attaches to the plug screws on. Put on lead of the ohm meter to one of the plug wire leads, the other end on each of the small wire post's, checking the reading one post at a time. Do the same for each plug wire. To check the primary side,attach each lead from the ohm meter to each of the smaller wire terminal's. That is your primary reading. Easy piesy. Your doing a good job, and asking for help is allways a good thing. However, having said that, there is allot of info allready covered on this site in the tech section. Look there after you read your manual before asking here. Some of us get a little frustrated typing the same answer's over and over again. You understand, right? RIGHT!!! Good luck, and DO let us know how it goe's, as we were all novice's once,too!!! Personally, I've been working on and modifieying vehicle's for over 45 years, and I, too, need some advice from time to time. And remember, there really is no Dumb or Stupid question's.