Drained oil for a week now bike knocks at 3000rpm - Page 3 - Kawasaki Vulcan 750 Forum : Kawasaki VN750 Forums
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post #21 of 27 (permalink) Old 06-02-2019, 10:38 AM
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Quote:
Originally Posted by GDI View Post
Yeah, I'm running 5W40 Shell Rotella Synthetic, too. Seems to be OK. . . .

The only thing that I notice is that the clutch *really* grabs when the motor is cold? I'm thinking that maybe I should try another oil on the next change to see if that makes any difference.

You all think the 5W40 might be causing the clutch to be grabby like that? Maybe the oil doesn't really matter?

GDI
That's known as Coffee Grinder Syndrome on the VN750. Warming the engine and moving the clutch lever in/out a few times in neutral can help avoid a problem on the first takeoff. But you should always be careful on the first couple of takeoffs anyway, keeping the rpms low and slipping the clutch until it fully engages. The rest of the day it should be fine, however mine did have CGS once after being parked a couple of hours.

There's info on the forum for CGS, drilling the clutch basket, etc. Seafoam treatment in the oil helped mine for a while, but it was back after a year or two.

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Last edited by Spockster; 06-02-2019 at 12:20 PM.
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post #22 of 27 (permalink) Old 06-02-2019, 12:06 PM
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I encountered that "coffee grinder sound a couple of times, along with the clutch grabbing. It was never a problem. I always warm up my engines before taking off, and that problem won't happen if you do. Let it run until the needle on the temp gauge reaches the second mark from the left. That indicates that the thermostat has opened and coolant is flowing through the system. I also make sure my clutch is not stuck before shifting into gear. In fact, for the first start of the day, after warming up the engine, I shut it off, put the bike in gear, pull the clutch in, and rock it back and forth until it rolls easily. The Vulcan clutch tends to stick overnight. The holding the clutch in I restart the engine with the bike in first. You can then ride away without that loud CLUNK. Those clunks put a shock load on the transmission parts. For the rest of the day it is never in neutral. I hold the clutch in at stop lights, and park it in first.

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post #23 of 27 (permalink) Old 06-02-2019, 12:26 PM
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Edited my post below to include....

CGS shouldn't be a problem after warmup and the first couple of clutch engagements, but mine did it once after being parked just a couple of hours. I ended up flat on my back with the bike laying down 20 ft away. Extended sissy bar hit me square in the back, and sheared a couple of bolts in the backrest.

Best to get in the habit of testing clutch action right after being parked for a while. This engine cools down quick.

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post #24 of 27 (permalink) Old 06-13-2019, 12:04 AM Thread Starter
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This will be sickest coffee grinder I know

Quote:
Originally Posted by Spockster View Post
That's known as Coffee Grinder Syndrome on the VN750. Warming the engine and moving the clutch lever in/out a few times in neutral can help avoid a problem on the first takeoff. But you should always be careful on the first couple of takeoffs anyway, keeping the rpms low and slipping the clutch until it fully engages. The rest of the day it should be fine, however mine did have CGS once after being parked a couple of hours.

There's info on the forum for CGS, drilling the clutch basket, etc. Seafoam treatment in the oil helped mine for a while, but it was back after a year or two.

Guys please help. I guess engine opening, but what am I looking here at. How can just oil change destroy motor like that? Was all fine I let oil dry for a week then change it and even did not ride at all. I am just slowly rising RPM just a bit, and it starts knocking.... Is there any centrifugal thing which could get loose? Any springs? It is a generator side or clutch side to open? Seems that clutch is fine, I can roll the bike without knocking up to 2500rpms. Getting higher and all hell brakes loose. What happens at 2500rpms in regular bike? Why such magic number?
Anybody? (oil level is all good)
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post #25 of 27 (permalink) Old 06-13-2019, 11:53 AM
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The clutch grab when cold is the coffee grinder syndrome. There is a mod to fix it (drilling a series of holes in the clutch basket). Works like a charm.

Also, the way to get the correct amount of oil is to pour 12 ounces out of the gallon and then pour the rest in the bike.
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post #26 of 27 (permalink) Old 07-05-2019, 10:56 PM Thread Starter
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Looks like I have broke something by adding too much oil. Anyone knows what it could be?
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post #27 of 27 (permalink) Old 07-06-2019, 10:33 AM
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What issues have you tried to diagnose? The easiest thing that creates a knocking/rattling is the automatic cam chain tensioners (ACCT's). Have you looked into those at all? If not do some searching on the forum for the proper fixes. I don't know if that might be your problem or not, but nobody here has ever heard of dropping the oil, then getting a knock.

- What have you tried to diagnose so far?
- Have you looked into the ACCT's?
- What type and weight of oil are you using?

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