SL350 Running Issues
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Thread: SL350 Running Issues

  1. #1
    Member LEGION's Avatar
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    SL350 Running Issues

    Hello Ladies and Gents. I haven't been around the forum for some time since selling "Herbie" the 1980 CM200 a while back to a friend. I've since had an SL350 land on my lap and I'm working on getting it running and could really use some help. Here's the scoop.

    I drained the gas tank and refilled it with 2 gallons of fresh 87 octane fuel. Removed both carb bowls and dumped out the old gas. A while back on a weak attempt to get it running I removed both carbs and gave it a good cleaning but this time around I didn't do this. That was probably 2-3 months ago.

    With the choke on fully it fired up in about 5 kicks. Sweet. Purred like a kitten actually but then I realized only one exhaust header was getting warm. Left side was hot, right side was dead cold. With the bike idling (on the left cylinder) I removed the right side spark plug wire and promptly got zapped but I managed to stick an inline spark tester and verify that it was getting spark. Next I moved on to fuel. I sprayed starter fluid straight down the throat of the right side carb and saw zero change in engine speed or header temp.

    The next place I went was either bad spark timing or valve clearances. The service manual I have states they should be .002" and .004" (I don't recall if those are intake or exhaust). The smallest shim I had was .006" so I rotated the crank to set each at TDC and verified the tappets were loose and attempted to put the shim gauge in the gap. No go. So they are all less than .006" and judging by the amount of slop I don't suspect they are less than .002" so I think bad valve clearances are unlikely. Perhaps someone here can shed light otherwise.

    Next I did a compression test on both cylinders and they were right around 150 psi by the time I got tired of kicking. Manual states 150-170 is normal and since this was done fairly cold I called that a pass.

    Then I opened the points cover and adjusted the point gap where the contacts open and close. Manual states they should be 0.3mm to 0.4mm so I adjusted them where the 0.3mm shim had very light drag and the 0.4mm caused visible opening to make it fit. Next I checked for spark timing by attaching a multimeter across one set of points and turned the meter to test continuity. I cranked the engine through its paces and rotated the whole plate until the points opened right at the F mark (which I think means the right side cylinder). In hindsight, I only did this for one set of points but I can't adjust them independently so was this okay?

    I checked the spark plug gaps upon reinstallation and found them to be in spec. Manual said .028"-.032".

    I buttoned everything back up and gave the bike a few kicks (took more than 5 this time around) but it fired up and alas... Still runs on only the left cylinder. Same symptoms. Has spark, starter fluid has no effect. No backfires no nothing.

    Can anybody shed light on what is going on here? Is the right side carb flooding the engine and that's why it doesn't run and starter fluid (more fuel) has no effect? When I put the fresh gas in I watched the fuel go through the filters and made sure the flow stopped once the bowl got full so I know the float valve works. Maybe a float height issue?

    Any help would be great because I'm stumped.

    Thanks in advance.

    -Harrison

    SL350 Running Issues-img_20170430_202023.jpg
    Last edited by LEGION; 05-01-2017 at 08:08 AM.
    1980 Honda CM200
    2007 Kawasaki KLR 650

  2. #2
    Senior Member doode's Avatar
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    Has spark, or got zapped? Those are two different things.
    Did you try new plugs? and caps and trim the ignition wire while you're at it?

  3. #3
    Member LEGION's Avatar
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    Quote Originally Posted by doode View Post
    Has spark, or got zapped? Those are two different things.
    Did you try new plugs? and caps and trim the ignition wire while you're at it?
    Thanks for the reply Doode!

    I got zapped in the process of removing the spark plug wire from the plug itself while the bike was running. I then placed an inline spark tester between the wire and the plug and saw a consistent flash. I didn't visually confirm there was a spark. I find it hard to hold​ the plug against the cylinder while kick-starting but it might be worth it just to triple check. I was using a spark tester like this.

    http://m.harborfreight.com/inline-ig...ker-69014.html

    While I had the spark plugs out I kept track of the left/right ones and compared them. The left side was dry and a light black. Right side looked a little wet and smelled like gas. Same gaps from left to right. Plugs are like new.

    I should've swapped the plugs while I had them out just for good measure...
    1980 Honda CM200
    2007 Kawasaki KLR 650

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  5. #4
    Senior Member doode's Avatar
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    I just reread your original post... You need to make sure the rt side points open at F on the correct stroke. Sounds like the left side is timed to LF, but the rt side timing needs to be set just as accurate. Check and confirm. You can adjust the open/close of each side separate from the plate

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    Member LEGION's Avatar
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    Quote Originally Posted by doode View Post
    I just reread your original post... You need to make sure the rt side points open at F on the correct stroke. Sounds like the left side is timed to LF, but the rt side timing needs to be set just as accurate. Check and confirm. You can adjust the open/close of each side separate from the plate
    I can't adjust the spark timing independently since both sets of points are rotated when I turn the points plate. Or am I missing something? Nonetheless i should have done my continuity test on both sets just to confirm. Now that I think about it though I actually was testing the right side because I remember it was just plain F and T. Not LF and LT.

    I should also pay attention to what's going on in the valves when I'm setting this because maybe it is off by 360 degrees. Previous owner "rebuilt it" so who knows. Hmm...
    helo75 likes this.
    1980 Honda CM200
    2007 Kawasaki KLR 650

  7. #6
    Senior Member doode's Avatar
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    You can loosen the top and bottom screw of each side and pivot it to open/close sooner/later.

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    Member LEGION's Avatar
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    Quote Originally Posted by doode View Post
    You can loosen the top and bottom screw of each side and pivot it to open/close sooner/later.
    According to the service manual those screws are only for adjusting the point gap and not the point timing. Regardless I don't think I'm dealing with a couple degrees off. Otherwise I would be getting popping or at least some sort of heat coming from the pipe right? I'm wondering if the spark is a full 180 degrees off or there's something weird and I'm getting no spark at all. I need to remove the plug and visually verify a spark to be sure.
    Last edited by LEGION; 05-02-2017 at 10:24 AM.
    1980 Honda CM200
    2007 Kawasaki KLR 650

  9. #8
    Supporting Member Yendor's Avatar
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    The correct process is to Set the Left Side GAP as close to the middle of the point gap range as possible then time the left side.
    The timing on the right side is then set by adjusting the GAP.
    As long as the Gap is within range when the right side is timed walk away, it's done right.

    To get any better you have to use a Timing light.

    Still the same process.
    Set the left then time the Right by moving the Gap. Double check the Gap is within range when timed.

    If the Gap is not correct, - Find what the GAP is on the right by checking with multiple feeler gauges.
    Then Move the Left Gap by Half by the out of range difference and follow directions above.
    1970 CB 350 CAFE - Current Project on the bench,
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  10. #9
    Member LEGION's Avatar
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    Quote Originally Posted by Yendor View Post
    The correct process is to Set the Left Side GAP as close to the middle of the point gap range as possible then time the left side.
    The timing on the right side is then set by adjusting the GAP.
    As long as the Gap is within range when the right side is timed walk away, it's done right.

    To get any better you have to use a Timing light.

    Still the same process.
    Set the left then time the Right by moving the Gap. Double check the Gap is within range when timed.

    If the Gap is not correct, - Find what the GAP is on the right by checking with multiple feeler gauges.
    Then Move the Left Gap by Half by the out of range difference and follow directions above.
    I'm going to start the process you described now just to be sure it's set right. In the meantime, do you see anything that's amiss? Still boggles my mind that it has spark and it has fuel but the exhaust pipe remains cold...

    1980 Honda CM200
    2007 Kawasaki KLR 650

  11. #10
    Member LEGION's Avatar
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    Update:

    I've set both point gaps to where a .308mm shim fits easily and a .406 causes noticable point movement when inserted. I've also rotated the crank while testing continuity over the point gaps and found the left side breaks continuity here:


    And the right side breaks continuity here:


    Both gaps are correct and the timing of the breaker opening is correct. Interesting enough, now I can't get the bike to run period. Not even on one cylinder. It's been hooked up to the battery charger and I've tried shots of starter fluid. No pops, no stutters no nothing. Also verified the blue wire goes to the right side ignition coil, yellow wire goes to the left side.

    I am at a loss here. Anybody have some ideas?

    Here is my current point setup.

    Last edited by LEGION; 05-19-2017 at 07:51 PM.
    1980 Honda CM200
    2007 Kawasaki KLR 650

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