1968 CL350 No spark to right cylinder

Edy

Hi folks, been awhile. Had to go out of town for a bit. Got the carbs back together. They were in great shape, really. The real culprit of the weak running is that it's only on the left cylinder. Changed plugs and the right is still pristine. Points look pitted but gapped correctly. I shined them up a bit with no difference. Anyone care to describe where to check for voltage with meter?

jayel · Posted: Sat Apr 04, 2009 5:38 am Post subject:

should see 12v at the b/w wire at the coil, with the points open check for voltage at the points wire, you will have some loss from being connected thru the coil and condenser, but that will tell if your getting any thing thru the coil or not, with the sparkplug out and laying on the head, with key on snap the points open and see if the plug fires, yes ok/no? = bad coil, condenser, spark lead or plug cap then switch the points wires and the spark leads to the opposite cylinder, problem move? = bad coil, condenser, spark lead or plug cap, doesn't move something in the carb or cylinder/valves

Edy · Posted: Sat Apr 04, 2009 8:22 am Post subject:

Thanks bunches. Thats just the kind of troubleshooting directions I needed.

Edy · Posted: Sat Apr 04, 2009 3:31 pm Post subject:

Good news- I'm wrong. The right plug does spark.
Bad news- Right cylinder still not firing at all judging by the condition of the plug and the cool temp of the pipe when the other side is running.
Did a compression test which was ambiguous to me. I could get the compression up but it leaked off quickly. My guage is some ancient el cheepo that's been rattling around in my vintage tune up stuff ( the stuff is vintage I mean)
Off to adjust the valves and time the bike.
At least the weather is cooperating. Froze last night but I'm in shorts and flip flops now. All of 65F I suppose.

jayel · Posted: Sat Apr 04, 2009 4:02 pm Post subject:

may have weak spark on that side, what does the spark look like at the points? yellowish/arcing = bad condenser, hot and blue is good, try some new plugs

Barchetta · Posted: Sat Apr 04, 2009 4:22 pm Post subject:

I spent the day freezing and covering the same problem. Mine was just the sparkplug cap, and the wire, coming apart. The spark got to the wire but not to the plug. The obvious solutions sometimes take me all day to resolve. Embarassed

I'm no pro.

But when I did finally work it out and fix it, I felt GREAT!

Question Edy:

If you're getting spark, how's the fuel flowing to that cylinder? When my cylinder wasn't firing, my plug was wet with gas. Even if the points aren't quite right, the cylinder should fire if there is gas. Are the right points arcing when running? I held a clean business card between the points and kicked it over until the points closed on the card. Then I pulled the card out to clean the surface. Worked for me. Or if the points gap was too much, that also caused the same problem for me. Hope you work it out, Barchetta.

Edit*
Yes X2 what jayel said.

Edy · Posted: Sat Apr 04, 2009 5:37 pm Post subject:

I did attempt to compare spark strength. I'm working outside because my garage is a north facing drafty structure that is cold enough to hang meat in. The sunny gravel drive and the picnic table are much nicer. After dark, I'll try again. Couldn't really tell the difference in the day. I don't see how the carb could be keeping gas from going to the cylinder. It really looked good. I put new plugs in it first off and the one on the right looks like it just came out of the package. The points did arc some though.

Between phonecalls and dyslexia with my feeler gauges, I'm only into the valves on the left so far. They seem tight. My feeler gauges are the ones I used on my old Toyota truck. Could they be too wide. Seems like the spring holder is a little proud of the valve stem end causing the gauge to bend in the narrow direction. Can that be so?

Just hope I don't find that the cylinder can't pull fuel into itself because of ring probems.

jayel · Posted: Sat Apr 04, 2009 6:32 pm Post subject:

don't rule out a bad plug just because it's new, switch the plugs side to side, did you try switching the points wires where they plug into the coils and switch plugwires to opposite cylinder? (in effect changing which cylinder the coil is trying to fire)

tbpmusic · Posted: Sat Apr 04, 2009 6:54 pm Post subject:

You said you gapped the points.

I'll bet your timing is way off - changing the point gap on these bikes also changes the timing.
There's a very specific procedure to follow - go here and read about it....

Timing Notes

Edy · Posted: Sat Apr 04, 2009 7:41 pm Post subject:

I didn't gap the points. I said "Points look pitted but gapped correctly. I shined them up a bit with no difference." That doesnt' mean the timing isn't off though and your writeup is great. I also probably misled Jayel by saying I replaced the plugs with new ones straight off. I meant that I replaced them as soon as I figured it was only running on the one side. Hope I didn't mess the bike up too much by riding it as a single for almost 20 miles after I first got it.

tbpmusic · Posted: Sat Apr 04, 2009 9:15 pm Post subject:

Barchetta · Posted: Sun Apr 05, 2009 6:54 pm Post subject:

If you're getting gas, and there is spark going to a new plug, tbpmusic is right. Timing is the likely culprit. Not the only answer, but the most likely.

Edy · Posted: Mon Apr 06, 2009 8:17 am Post subject:

Thanks you guys. I'm now awaiting a new set of points and condensor. I figured if the timing is picky, I want to do it with new points. You'll probably hear from me next weekend.

Just to rule out any weirdness, what would be a good way to confirm that I have gas to the cylinder?

Barchetta · Posted: Mon Apr 06, 2009 10:47 am Post subject:

I'm no pro, but when my cylinder wasn't firing, I could pull my sparkplug and the electrode was wet with un-burt gas.

I heard a tip that I don't know if it's true or not. Supposedly it's a dirt biker trick for clearing fouled plugs after you drop the bike and can't get it started.

With a rubber glove, you hold the spark plug cap just off the plug so that the electricity arcs to the plug, in the cylinder. Sometimes I got a little backfire, but it was enough to get the cylinder going again. If anyone knows what I did was wrong, please say so. I don't want to hurt my bike, or anyone elses. I was hundreds of miles from my garage when I used the trick, and it at least got me home.

Edy · Posted: Mon Apr 06, 2009 11:25 am Post subject:

Well, that plug was dry and shiny after running on the other cylinder yesterday. Looks like its back to the drawing board. I just never thought that the carb was the culprit because it was in such good condition. Now, I'm finding posts that talk about one side of the petcock clogging. Will try to find the time today to check it out.