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Discussion Starter · #1 ·
Well......it looks like (possibly) back to square 1. I was having a problem with the left cylinder not firing. I found that the timing on the left cylinder was off slightly. Made the adjustments and fired her up. I was getting great compression out of the left exhaust, but, the left side was ice cold. I was trying to let it warm up a little and see if that helped. It idled for a minute or two, max, while I was trying to adjust the right carb so that the bike wouldn't over-rev and slightly adjusting the air/fuel as well to try and remedy the spark plug tells. When I shut off the engine, I noticed a fountain of oil coming out of the engine on the left side. It may have been my eyes catching the oil, but it appeared to be spewing out. I've attached pictures and I, foolishly, cleaned a lot of the oil before taking the pictures. I can't tell if it's coming out of the spark plug or if it's coming out of the exhaust header.
A few things to consider:
1)I recently rebuilt the entire engine including new piston rings. I am almost 100% positive, that I clocked them according to the factory service manual.
2)The bolt to hold down the cylinder head/spark plug onto the cylinder head/piston recently stripped out. I had a machine shop put in a helicoil and I was able to lightly torque the bolt. Now, bear in mind, the engine passed the compression test and passed a leak down test.
3)I removed the studs to the exhaust on the left hand cylinder to make it easier to mount the engine. I had no issues with the studs coming out or going back in. I used red-loctite on the studs and put them in to the depth they were previously.
4) Finally, while trying to read the spark plugs, when I pulled the right spark plug today, there was a small amount of white smoke coming out of the spark plug hole. I was unable to determine if that was oil or fuel, however, it was minimal and I shook it off.

Where do I start? I feel like we're going down to the lower case at the bear minimum. Honestly, if I'm going to do that, I am somewhat considering splitting the cases to re-inspect all of my previous work. I know this adds weeks to my build, at a minimum, but now that I've had to go back and re-do the top end multiple times, I'm not as confident in my work on everything else. I would rather not have everything dump on me after getting to ride for a day or two. Can anyone help me decide where to start? What a likely culprit would be? What the next steps are? Maybe other life choices I should re-consider haha. I'm a little deflated and feel beat down but I know this a learning experience. I want to thank everyone who has helped me so far with advice and I look forward to getting this right. Hopefully, it's something simple that I bone-headed up.


Oil 1.jpg
Oil 2.jpg
Oil 3.jpg
 

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Did you put new gaskets in each cam holder bearing? And new orings on rocker arm adjuster rods too? Did you clean gasket areas really well, i mean no old gasket left anywhere? Because it looks like the oil is coming from the cam bearing end holder.

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If the cam bearing gasket is on backwards, it will not line up the holes properly and will pinch the o-ring on one of the valve adjuster eccentric shafts and cause the leak. Not likely any damage, but to properly replace the gasket the engine needs to come out of the frame on a 350
 

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So you have two issues, the left side not firing and an oil leak? Is the spark plug wet on that side? Wet with gas or oil? The left side cam bearing gasket can be changed with engine in the frame.
 

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Is there a spot where all valves are closed, Mike? that would be the only safe way, since the top cover can't be removed in the frame IIRC
 

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Supposedly, there is a spot where they are all closed. Be easy enough to slack off all the valve adjustments to make it easier to find. Of course if it's leaking out of the cam box/head joint it has to come out any way.
 

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Discussion Starter · #7 ·
The ring around the spark plug is wet but the spark plug itself didn’t appear to be. I’m more concerned about the literal fountain of oil that appears to be coming out of the spark plug and exhaust headed. The oil seal on the left cam is brand new and installed correctly. The gaskets were all double checked going in so as not to block the oil passages. I’m finding it hard to believe it’s just a gasket issue. This shot out with pressure on shut down. Or it appeared to. Again, it could have been the shock of me just seeing oil everywhere. I could be wrong though and it could be a gasket. I have just tripled checked those and the seals when installing.
 

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Oil is pumped upstairs around a cylinder stud to oil the top end, watch around the corner of the head gasket and the cam box joint to see if it's leaking there. Ring gap placement has nothing to do with an external oil leak, it has to be a gasket or a seal. Breather tube open?, Tried running it, with the dipstick loose, to vent crankcase pressure?
 

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Discussion Starter · #9 ·
Oil is pumped upstairs around a cylinder stud to oil the top end, watch around the corner of the head gasket and the cam box joint to see if it's leaking there. Ring gap placement has nothing to do with an external oil leak, it has to be a gasket or a seal. Breather tube open?, Tried running it, with the dipstick loose, to vent crankcase pressure?

If the rings weren’t clocked properly couldn’t they cause oil to slip past them? I’ll check out venting it this weekend for sure to see what happens and now I’ll know to keep an eye on the area. I appreciate all the help here too, I’m just walking through my thought process. To get all the valves to close, I believe you just have to be 90° past TDC. That’s what I typically do to adjust the cam chain.
 

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If oil gets past the rings it comes out the exhaust pipe, not the outside of the engine.
 

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Are both of your ignition coils good? I believe a bad coil could affect a properly firing cylinder ... if you run out of options, try switching the ignition coils and see if the problem moves to the other side ...
 

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I had something similar happen on a 175. A BRAND NEW spark plug wasn't firing and causing one cylinder to not fire. Check your plug and check your coil like KnuckleBusting360 said. Also, remove the alternator cover and let all the gas and oil drain out before doing anything else. You'll probably drain half a gallon if you've been trying to ride it with one cylinder.
 

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Discussion Starter · #14 ·
It appears to be a gasket! I’m quite relieved. Is it possible to remove the points housing without pulling the engine? What are the possible downfalls? If I have to pull the engine to redo that then I’m going to have to go down to the head gasket. It wouldn’t be the worst thing but.......a small risk to avoid it wouldn’t hurt my feelings
 

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Can be done without pulling engine from frame, as you do not generally need to loosen head-stud nuts.....

But it's not particularly easier that way...Phone......
 

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Is that exhaust stud exposed going into the head? Is it me, or is there a big chunk of aluminum missing there?
 

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I was able to do both cam bearing gaskets and all the adjuster o-rings with my engine in place in the frame not too long ago. '71 CL350.
I simply rotated the engine to 90° past TDC where all valves are closed (I have stamped a small mark into the rotor to make this spot easier to find just for convenience), slacked all the valve adjusters, and removed the cam chain tensioner from the back of the engine (four bolts, not too difficult to get to from the throttle side with CL pipes).

I then carefully and methodically removed the points side bearing, being sure not to put any lateral or axial pressure on the camshaft, cleaned up all the mating surfaces, replaced both O-rings, and applied a light film of Bel-Ray grease to the gasket itself (makes positioning the gasket easy as pie during reassembly), once that side was done, I simply rinsed and repeated for the tach side.

Both gaskets can be accessed with the engine in the frame, just takes a bit of patience and a lot of care, and a steady hand... just my $0.02

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Discussion Starter · #19 ·
Well, turned out to be a backwards gasket. Bone headed move. I wound up leaving the engine in the frame. Rotated until all valves were closed, removed the cam chain tensioner and shockingly was able to remove the points cover with ease. I took Sprint’s advice and noticed the gasket didn’t look perfect on the housing. Simple fix and had I felt any pressure when removing or installing the housing I would have bailed to pull the engine. Bike fired up fine after I reinstalled and adjusted the cam, valves and points. Now to figure out why the left cylinder isn’t firing haha. I’m going to “swap coils” and see if that’s the issue. It’s not timing, and brand new spark plugs. I’m just hoping the coils are tired or something is grounding at the points connection. Will update soon. Thanks for all the help!!
 

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Backwards gasket, huh... ;) glad it was something simple. As for your ignition problem, check your points wire connections - if the terminals are turned the wrong way one of them will touch the points cover and ground it. If they're not already, turn the spade connectors like this - then they won't touch the cover

points.jpg
 
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