Gurgling and popping on left side/rear cylinder - Kawasaki Vulcan 750 Forum : Kawasaki VN750 Forums
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post #1 of 6 (permalink) Old 06-14-2017, 07:07 PM Thread Starter
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Gurgling and popping on left side/rear cylinder

I have an 88 that I've juuuust about got ironed out, but I need a more seasoned ear to help me diagnose. I'm ear-shaven, coastered, degoated, and running straight pipes. I hear this prevents good compression on the short pipe, my problem side, and I'm not sure if my PO rejetted. Have tried a few 24hr seafoam baths, to no avail. Just finished up this afternoon with dropping the bottom of the carbs and running a guitar string up through the pilot. No change. Tried the blowback method. No change. Set my intake screws to 2.5 on both sides to have at least some sort of control variable. I've been keeping it on the center stand because my cork seal around the stator case drips a tiny bit, so I'm not sure if symptoms would show if I had a stuck float (leaking gas out of pipe/into oil). And I'm a carb virgin although I've successfully executed the tuxedo mod (while mounted) and had no problems working around them today, I'm pretty dexterous and persistent. Also I've attached a photo of the bottoms of the carbs, which may end up confirming that I need to pull them, but when looking up into them with a flashlight, they are perfect looking, no yellow varnish at all. Shops around here will only touch it for a rebuild, which runs around 600 and I'm not about that. Please, any suggestions would be helpful, and I'll post the clip of it running asap, though these phone mics aren't exactly scientific instruments.

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Last edited by lVluffin; 06-14-2017 at 08:12 PM.
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post #2 of 6 (permalink) Old 06-14-2017, 08:39 PM
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That pic yo! yuck! Did you soak the carb bodies?

Actually it doesn't sound too bad, short clip though, and no revs. It's probably gonna burble with the pipes like that.

Only thing I can think of... Maybe, only maybe, a little bit of a sticky valve. Need to put some miles on it if it's been sitting a lot. But it could just be the stubby pipe.

The short pipe won't lose compression, but low-end torque will suffer some. Where mine can cruise and pull away from 2300rpm, yours may need to be maybe, 2500-2700 or so. Not sure of exact numbers, my exhaust is all stock.

Is it that little putt-putt at the pipe that concerns you? I'm thinking it's the pipe, but sluggish valve closing will do it too. It wouldn't be sticking enough to cause a rocker to tap, just leaking a bit. Riding it can clean up the valve stems, it might go away on it's on if that's the case.

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post #3 of 6 (permalink) Old 06-14-2017, 09:56 PM Thread Starter
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yeah the struggling sound concerns a bit, but i figured i was only going to be able to mitigate it, if not completely eliminate it. but i like the "ride more" solution, i can get with that. Ive got plenty of seafoam in the tank, and in the oil as well with the last change which was only a few dozen miles ago, so hopefully it clears up. I'll get it out tomorrow afternoon and see how she does nice and warmed up. hopefully its nothing (read:hopefully im not making anything worse), but i come from the plain jane car world so anything but absolute normal sounds like it hurts. im get a little bit of carb sneeze on occasion, which seems to confirm your sticky valve diagnosis. wish me luck! the stator is the only thing thats stranded me yet, and id like to keep it that way.
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post #4 of 6 (permalink) Old 06-15-2017, 10:15 AM
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Seafoam in the oil and gas is a good start, as was the seafoam soaks, but those carbs are NASTY inside if that's what yours are looking like on the jet covers. I would pull them and deep clean them, for sure, and probably check the jet sizes. I have pod filters on mine and stock exhaust and run 142/42 (4 sizes up from stock) so you could probably benefit from the same treatment, seeing as mine are likely just a tad too rich for my setup (read: probably good for yours)

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post #5 of 6 (permalink) Old 06-16-2017, 10:40 AM
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You should use a higher octane ovaltine

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post #6 of 6 (permalink) Old 06-17-2017, 05:09 AM
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Originally Posted by Goofyfoot2001 View Post
You should use a higher octane ovaltine

If you ever need someone to watch your chocolate milk /b/ro, I got ya =)

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