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Discussion Starter #1
When I start my bike cold (especially mild outdoor weather), I have a knocking noise in the front cylinder. It starts when I run up to 2-3k and continues as it comes back to idle for a few seconds, then suddenly stops knocking. As it warms up, it takes more revs to make it happen, and it stops sooner upon reaching idle. It stops knocking altogether by the time the temp guage hits the 2nd line (maybe sooner?) and doesn't knock again until the next cold start. Oil level is halfway between marks. 11,531 on the odometer. Original ACCT.

Any ideas?

Cold start. Knocks at idle after revving, then stops like a switch is flipped.

A bit warmer, but still not up to temp. Notice how it stops immediately upon hitting idle?
 

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Could be a sticky lash adjuster. Seafoam in the oil can help, I run it 200 miles before an oil change, just when I feel it needs some internal cleaning, not every oil change. Cleans valve stems too.
 

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Discussion Starter #3
I put some seafoam in the oil. I'll change it after about 200 miles and see if the knock clears up.
 

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Could be a sticky lash adjuster. Seafoam in the oil can help, I run it 200 miles before an oil change, just when I feel it needs some internal cleaning, not every oil change. Cleans valve stems too.
How much do you add to the oil?
Thanks!
 

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Discussion Starter #5
It was either 1 or 2 oz per qt. I wanna say 1. So a total of 4 oz.
 

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I ended up getting sick last week and not riding much. Fortunately not COVID. Believe it or not, other illnesses still exist :LOL:. I ran seafoam in the oil for 200 miles, then changed the oil. The old oil was dark, but otherwise very clean. No hints of metal, and noting in the screen. No improvement to the knocking sound when cold. I'm fearing I need to have the cylinder head redone.

A guy I know wants $400/head plus parts to go through them. That doesn't include the labor of pulling the engine (which I'm able to do) I'm really unsure what to do.

Part of me wants to sell it now before it becomes a major issue. Part of me wants to repair it no matter the cost. Part of me wants to ignore the problem until the end of season and then decide between the two options above. But ignoring it may lead to catastrophic failure and force me into the third option of junking it!

After my last bike, I don't feel comfortable working on the engine internals myself.

Advice? Opinions? It's a 2005 with 11,800 miles on it.
 

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I ended up getting sick last week and not riding much. Fortunately not COVID. Believe it or not, other illnesses still exist :LOL:. I ran seafoam in the oil for 200 miles, then changed the oil. The old oil was dark, but otherwise very clean. No hints of metal, and noting in the screen. No improvement to the knocking sound when cold. I'm fearing I need to have the cylinder head redone.

A guy I know wants $400/head plus parts to go through them. That doesn't include the labor of pulling the engine (which I'm able to do) I'm really unsure what to do.

Part of me wants to sell it now before it becomes a major issue. Part of me wants to repair it no matter the cost. Part of me wants to ignore the problem until the end of season and then decide between the two options above. But ignoring it may lead to catastrophic failure and force me into the third option of junking it!

After my last bike, I don't feel comfortable working on the engine internals myself.

Advice? Opinions? It's a 2005 with 11,800 miles on it.
Damn! $400/head is awfully steep. Especially if he's not pulling the engine.

You think that $5 stethoscope would help you any?
 

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Sounds like a once-per-revolution thing. Doesn't sound much like a bottom-end issue. Doesn't quite sound like the chain slap of loose ACCT's. I'm a bit puzzled.

Yes, Spockster's idea about a stethoscope is a good one. Harbor Freight has ones for super cheap, helps to identify wherabouts it's coming from.

~12,000 miles isn't much on an '05, so maybe something is sticky.

Does it stop doing it once it's fully warmed up? I do notice it goes away at idle for sure, like you said. I wonder if it could just be quieter than the engine mechanical noises at such low revs and loading.
 

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I keep thinking, if it's not ACCT, it must be a lash adjuster or rocker arm slapping.

The stethoscope does work really well, I've got one.

Is it vibrating much? I've never heard balancer noise, but that's always a possibility.
 

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Discussion Starter #13
I took a video this morning, and I was waiting for it to upload. It's a cold start. The video is me holding the phone and going from side to side, so there isn't much to look at. At one point, it's a close up of my collar and neck! However, you can get a better idea of the noise.


It's loudest at low idle. Above idle (including running on choke), the exhaust tends to drown it out.
I turn off the choke at ~1:30 and you can hear it better.
It's louder on right side (I remember it being louder on the left, but that wasn't the case today).
At ~3 minutes, the noise suddenly stops. It comes back whenever I rev up, and then stops again after settling into an idle.
Once fully warmed up, it stops altogether, regardless of engine RPM.

I used a long screwdriver to my ear to try to find the source of the noise.
It's definitely the front cylinder rather than rear, and it's definitely not in the crank area.
It seems louder at the top of the cylinder, rather than the top of the cylinder head, but I'm not 100% confident on that.

There's no significant vibration to suggest a problem with the balancer.
And there's no change to the vibration or running characteristics between when it's making the noise and when it's not.
I don't run WOT before it's warmed up, but it doesn't feel down on power at partial throttle (other than what would be expected with a cold engine).

I don't know what kind of oil was in it, as it was changed just before I bought it. I just hit 3k so I changed it.
It's now running Amsoil 10W-40 Synthetic Metric Motorcycle Oil.

I should just throw on my MCCTs and verify that doesn't affect it. But I wouldn't expect ACCTs to suddenly start functioning after warming up.
 

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To your last point, when my ACCTs started to fail the noise always went away when the engine warmed up. I didn’t wait long before swapping them out.
 

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Jason, I sincerely hope you can get this sorted out & it turns out to be minor.
Hydraulic lifter not keeping up? Or slow to pump up cold? Exhaust leak? Sounds to to be in the valve train to me. To many products claim to free up sticky lifters to recommend one .
I have heard of replacing some oil with an equal amount of marvel mystery oil, , running for bit and changing oil.

I’m sure you probably have ruled out exhaust leak by now.
 

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Lifter is the only thing I can think of that could come and go like that. Of course a sticky valve could act the same way.

I used to put a quart of Riselone in really old cars. But, the seafoam should have helped.
 

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