Author Topic: CL350 - left cyl drops out under load  (Read 611 times)

Offline CL_Dan

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CL350 - left cyl drops out under load
« on: Oct 06, 2017, 22:58:27 »
Running into an issue with a CL350 I picked up a few weeks ago and could use some help troubleshooting.
1973 CL350
Cheap pods - mains and secondary jets bumped up a size. Cant remember exact numbers off the top of my head.

Bike ran fine for a few weeks. Started it yesterday and lost the left cylinder at anything over 1/4 throttle. Could release the throttle and hit it again. The left cyl would come back, but only to 1/4 throttle before dying again. Pulled the carb, no gunk, no sticking, no crap in the jets.  Replaced the points, plugs and fuel lines with no change.  Compression test shows around 150 for each cylinder.  The issue is only when the bike is under load.  I can sit in neutral and rev all day with no issues.  I've seen a few threads with issues kind of like this, but nothing exact.

Any thoughts?
1971ish CL350 - current project
1975 CB125S
1975 CB550 -Sold
1969 CL450 - Sold it

Offline Sonreir

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Re: CL350 - left cyl drops out under load
« Reply #1 on: Oct 09, 2017, 12:57:05 »
Usually, if you're dropping a cylinder on a Honda twin with two ignition coils, the very first thing to check is the battery. It may look just fine to a voltmeter, but it's possible it's bad.

That said, I suggest another quick check check before you replace parts:
Grab a strobe light and check the timing advance on both cylinders. Make sure your timing is correct at idle and at full advance.

If you need instructions, let us know.
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Offline CL_Dan

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Re: CL350 - left cyl drops out under load
« Reply #2 on: Oct 20, 2017, 17:28:00 »
Sorry for the slow response, I've been traveling for the past few weeks and havent been around the bike. I'll try to verify the timing tonight.
1971ish CL350 - current project
1975 CB125S
1975 CB550 -Sold
1969 CL450 - Sold it

Offline advCo

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Re: CL350 - left cyl drops out under load
« Reply #3 on: Oct 20, 2017, 17:44:05 »
Change your plugs. Was just having a similar issue on a CB200.
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Offline runmikeyrun

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Re: CL350 - left cyl drops out under load
« Reply #4 on: Oct 23, 2017, 08:22:57 »
Check to make sure you don’t have a crack in your coil or wire.  These components get old and the insulation breaks down and cracks.  Often the wire is leaning close or onto the cylinder head fins etc.  Electrical shorts there will be most pronounced under a load.  If you have a test light clip the lead to ground, start the bike, and move the test point over the length of the wire and around the coil.  If there’s a crack a spark will jump to the point and the bike will stumble. 

Another possibility is it is arcing to the frame, bracket or gas tank.    If you can’t find it with the test light (or don’t have one) run the bike outside at night or in a dark area (don’t asphyxiate yourself!) and spray the area with a mist of water from a spray bottle.  Any short will again produce blue sparks and a drop in idle. 

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Offline MotorbikeBruno

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Re: CL350 - left cyl drops out under load
« Reply #5 on: Nov 03, 2017, 16:25:54 »
You mention the carbs are clean, but what about fuel level?  Could have one that is getting fuel and the other has fuel, but not high enough to deal with the snappy throttle?  I'm voting points/condenser/timing typically, but I've seen some odd things happen due to fuel level and how fast the fuel fills up in the bowls. (some times someone bends the wrong tang and it's actually the float stop tang and doesn't allow fuel in fast enough).

Hope you get her sorted.