Running on one cylinder

[mikes bikes]

I was out on a ride, everything running great, then all of a sudden, for no apparent reason, one side stopped burning fuel, we limped home, did some troubleshooting, made some changes, not sure what to do next. The bike will start first kick but is only running on one cylinder, one side seems fine with blue smoke coming out backside, the other side has no smoke coming out and un-burnt fuel dripping right out of the exhaust port onto the ground, I tested for spark best I could and thought one side looked weak, so I have replaced spark plugs, wires and coil, which has not fixed the problem. I have read all the posts, some suggest it could be reeds, stator, cdi or ground, thought I would check-in with you guys first, what do you suppose I should try next?

1984 RZ350, 9K miles, all original except for pipes, intake and jet kit

[gpaddict]

have you checked the compression?

[MK]

First (and easiest) : get off the pipe on the affected cylinder and look into the exhaust port.
Any carnage will show up immediately.

I suppose the usual piston damages because running only one side is not possible due to electric issues.
And the last left cause "carburetion" usually is clogged idle jets or maybe an air passage. But this usually does not happen during a ride from one second to another.

[mikes bikes]

Okay, I took the spark plugs out, slowly turning engine over reveals no funky sounds or noises. Placing finger over plug holes while turning over, movement and compression feels normal and equal. I took off the carbs and reeds, all looks fine with no obvious piston damage from the intake side. Did not look in exhaust port side yet as those exhaust springs are a bitch to get on and off. Ordered a new compression tester, arriving this week, will update. Thanks.

[MK]

https://www.amazon.de/ShiSheng-Federhak ... th=1&psc=1

[MK]

And I'd correct my statement regarding the carbs.
I remember one case where a main jet came loose during operation. This made the affected side die out, too.

[mikes bikes]

Thanks MK, the carbs are off now so I will check the jets this week too, will update.

[mikes bikes]

I did a compression test and things went well, I got the same readings on both sides. I also finally took apart the carburetors and may have reason to celebrate, the right side pilot jet screw had come loose and it fell out, never had that happen before, hopefully that explains things, I will get things put back together and provide another update. Fingers crossed.

[(F5)]

Haha. I was thinking jet fell out. Have heard of that before. Will foul plug pdq.