Drained oil for a week now bike knocks at 3000rpm - Kawasaki Vulcan 750 Forum : Kawasaki VN750 Forums
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post #1 of 27 (permalink) Old 04-02-2019, 07:18 PM Thread Starter
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Drained oil for a week now bike knocks at 3000rpm

Bike was running perfectly for last 11k. No issues smooth and relatively quiet 🙂
Then I decided to change oil little different way. The one I use is Rotella 5-40. This time however I did not warm the engine before oil drain. I just open the drain thing (as you know it is not exactly a bolt) and just left it drain for a week. After adding a gallon of oil and new k&m filter I started the bike. It is running very nice up to about 3000rpm, then starts to knock like it will have broken pushrod, or half engaged gear. I am afraid to get it to that level. But as far as riding under 3000 is perfect as it was before. I do not believe this is chain tensioners. It is way too sudden. Any ideas?

Last edited by jpiterow; 05-27-2019 at 12:55 AM. Reason: Added promised videos of the problem
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post #2 of 27 (permalink) Old 04-02-2019, 07:37 PM
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I'm definitely not the guy you're looking for on this forum. I'm a newb. But why would it matter about running the engine? I just changed my oil 2 days ago and I followed an oil change procedure described on this site. It said nothing about running the engine first. It started with "place the pan under the drain plug". Did I follow the wrong procedure? I'd imagine someone would have said, "Hey, don't forget to run the engine first" if there was a danger of damaging the engine.

So my question is, why would not running the engine first cause engine damage?

Also, is there another thread describing the oil change procedure that explains all of that? Do I need to change my oil again?
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post #3 of 27 (permalink) Old 04-02-2019, 10:12 PM
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Running the engine a smidge before draining is to warm the oil up so it will flow easier, that's all.
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post #4 of 27 (permalink) Old 04-03-2019, 02:37 AM
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I've never been able to get a gallon of oil in mine.
Usually around 3 3/4 qts. is plenty.
Oil should not be above black line at top of sight glass when sitting on center stand.


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post #5 of 27 (permalink) Old 04-03-2019, 11:28 AM
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Ditto on what Roadpouring said. Overfilling can cause issues. Double-check your sight glass. There should be an air bubble at the top after you've given the oil time to all settle back into the pan.

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post #6 of 27 (permalink) Old 04-05-2019, 11:23 AM
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Over filled or maybe go up to midgrade or premium gas and see if the knocking stops.

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post #7 of 27 (permalink) Old 04-05-2019, 11:35 PM
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I'm wondering if maybe the hydraulic tensioners might "drain down" if the bike sits long enough? I do know the engines in these bikes make enough noises to drive you crazy if you let them.

I had some very serious concerns after I did the tuxedo mod last year. I started the bike up and there seemed to be a loud knock. I let it idle for a while, and it seemed to get only marginally better. I was worried that I'd messed up the mod and maybe the stator was causing the noises. I pulled it back apart and looked it over, and it didn't look like anything was going on that would be making the noise that I was hearing.

I ran it that way, and it got noticeably better. Ended up going to MCCTs anyway. . . .

It's a noisy engine.

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post #8 of 27 (permalink) Old 04-08-2019, 02:38 PM
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WAYYYYYYYYYYYYYYYYYYYYY to much oil. Drain it down to the point where others said to, and then try to see if the knock goes away

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post #9 of 27 (permalink) Old 04-08-2019, 10:21 PM
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First things first. Unless you live at the north pole, you should be using 20w50 oil. 5w40 is to thin to provide protection for the bearings under load. It has a very low film strength compared to a heavier oil. I can't remember exactly how much oil I put in my Vulcan 750, but it seems it was very close to 4 qts. On the centerstand, you should fill it up VERY SLOWLY until it just touches the top of the sight glass (not the line cast into the case next to the sight glass) If you think you have too much oil in it, siphon out some until you see a tiny little bubble at the top of the sight glass, and leave it there. You will notice that when the engine is running there is no oil visible in the sight glass. That's because the sump is mostly empty, the oil is circulating throughout the engine. What happens when you put too much oil in an engine is the crankshaft will hit the oil in the sump. The engine will feel sluggish and very low on power. And it will blow oil out the breather. The first thing I would do is drain that 5w40 out of it, and fill it to the proper level with 20w50 oil and see what happens. If there is still a problem, it is not likely oil related. Also I always use Emgo oil filters on the VN750. I won't use anything that says K&N or Fram on it, though I don't know if there is a problem with K&N oil filters or not. Fram oil filters are junk.

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post #10 of 27 (permalink) Old 04-09-2019, 08:12 PM
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I have to ask why you run such a heavy weight oil? I do think 5w40 is too light. Book states 10w40. I've always kept with the suggested weight and never have had issues. I do see you're in Arizona so maybe it's the hotter temps there. As for K&N, I've not had issues with their filters.
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