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Discussion Starter #1
I have a Vulcan 750 2002. It picked up a bad vibration within the last two weeks so much my right foot gets really numb. SHe also wasnt running right, hesitating, low on pickup at times, so even after sea foam I decided to pull the carbs and clean them. They were gunked up a bit and after a bit of learning experience they are on the bike again and it runs great... But the vibration is still there. I bumped one of the coolant hoses into the rear cylinder so I had to drain some coolant and replace the O ring. I noticed in the coolant metal filings or shavings. Looking on the diagram the water pump is directly beside the right footpeg. I am wondering if anyone thinks or had this problem that the impellar is causing the vibration. Has anyone changed this? How much time is involved. It doesnt look that bad to do. One more thing, I read somewhere on this forum that if the oil is overfull that that could cause vibration. When I bought it used from the dealer earlier this year I noticed that the oil is wayyyy full. I asked the dealer and he said it was fine and they fill all their bikes that full. I dont believe them. All info I read says fill between L and H when on centerstand. That is why I may take her to a private shop if I can find one. Actually if I can do it myself, I would. Its hard to find good reputable mechanics especially the dealers. Sorry to ramble but the oil is free of debris. I dont think it is the dampeners. Any thoughts. BTW engine mounts seem tight.
 

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I would say probably old rubber in the engine mounts is the source of your vibration, but you could also put a vacuum gauge on the cabs to make sure they are in sync. If there are metal shavings in your coolant you probably do need a new water pump and a coolant flush, but that's not necessarily a symptom/cause of the vibration.
 

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You need to ride a sporty sometime if you want to know what vibration is. No VN can ever vibrate as much. My pegs are like giant rubber cushions. Without them it would be impossible to ride for more than a few miles. So don't get too freaked out about the vibes. Check the bolts on the peg and make sure they are secure. Sometimes it's that simple.
 

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Discussion Starter #4
Yes I have heard that about the Sporty. The carbs are synced. It just started doing this a lot, more that what I think is normal.
 

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Haven't read of any vibration from the water pump, but it does involve bearings and a shaft.

I wonder if the oil screen was pulled from the left side and what it looked like. If not, I'd want to see it to be sure it's not vibrating from the dampers.
 

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1986 VN750
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Balance dampers is another thing to consider. When they wear out the engine vibrates more, and it leads to some pretty nasty failures.
 

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Discussion Starter #7
I was wondering about the dampers. I put 4000 mi on since March and at the time the oil was really clean. It is very dark now but I saw no debris. I could take a look at the screen.
 

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Rubber from deteriorating dampers will collect in the oil screen. If the damper gear is grinding the case, there will also be aluminum shavings. The gear will eventually cut a hole in the side case once the dampers fail completely.
 

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Engine mount bolts can be tight, but that doesn't mean you can't have loose rubber from shrinkage. (TWSS)

High engine oil will definitely not cause vibration... nor low oil.. nor any other fluid levels. Keep the oil level within spec. No need to overfill on this engine, and don't go back to that "mechanic". It's not a Chevy 2.2. If you mean check the oil yourself, for sure. Do that regularly. You still have a centerstand, right?

I'm not sure on this engine if you can scope to physically see the balance dampers. If you can, do that.

Metal shavings are a really bad sign. Like others said, inspect the screen, and did you cut open your oil filter too?
 

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Discussion Starter #12
Good idea cutting the filter. I must check that. The screen is really clean, no particles or debris. I oredered the impellar and seal today and the other parts. I figure the filings coming from somewhere and that is the most logical, right? I will tackle that job in a week when I get everything. If that s not it I must look elsewhere. My list of things to do to the bike for this winter is growing.
 

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Discussion Starter #13
Screen is clean - No debris at all - I ordered the parts for water pump impeller replacement and seal. I guess thats where I'll start.
 

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Have you put it on the center stand and checked out the vibrations at different RPM’s? A “buzz” is not what I would expect from the dampeners but could be. Shavings are another thing. (Are they magnetic?) The V twin nature of the Vulcan is not the same as a Harley so your vibrations will not be the same. My H2 will buzz your hands numb after a tank of gas. It has no rubber mounts for the engine (great Japanese engineering!!) and the mirrors are just for looks. It would seem as though you could have a engine mount failure. Easy to check, one at a time. You could have a water pump issue but are you losing any coolant or seeing water in the oil? When you crack the side drain plug any water (if you are on the side stand) if drain off first. Try and catch the first drops in a jar. You will see water in it separate right away. The impeller and shaft are steel and the case aluminum so if they are touching it could only happen if you lost the C-clip that holds the shaft in place. Not a good thing but best to catch it now if that has happened.

My son and I are replacing the mechanical seal on his bike again because the last one didn’t last overnight. I have searched the forum for similar issues with the seal but most guys with this problem did not post what the final result was.

Keep us informed and good luck.
 

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Discussion Starter #16
Got parts today finally. Going to pull off crankcase cover and check water pump. Also do coffee grinder mod.
 

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Discussion Starter #17
Oh yes - on center stand it still buzzes - especially at higher rpm. I am pretty convinced its not a riding issue ie bad tire etc. I dont like the idea of the shavings, and no they are not magnetic. My plan is to do a visual on water pump. As far as I can see there is no water in the oil. I have not excluded engine mounts. Will keep you informed. Looks like this Saturday will be my cycle work day, so Im hoping for good results.
 

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Discussion Starter #18
Ok so i didnt like the metal chips in the coolant so I ordered a new mech seal and impeller and o rings. The mech seal wasnt in the best shape, dont know if that would cause my vibration or not but... the shaft has some lateral play, maybe quarter inch. Is this normal. It seems tight otherwise. and on the right side balancer idler gear the washer is not connected or held in place by anything. It has wear marks on it. I know the cover does some of it but should it ride on the gear like that. the exploded view doesnt show too much. Pic attached if I can do that right.
 

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Discussion Starter #19
Update - Having pulled the engine, and found that the mechanical seal and bearings of water pump to be really bad, I decided to split the crankcase open and replace the waterpump shaft bearing. Im glad I did. It had a lot of play. The other thing I found was the balancer shaft was really wobbly. I think that was the real source of my vibration. The rubber balancers looked good but I decided to change them anyway. I ordered new bearings for balancer shaft. Lets hope that was it but from the look of the condition of these bearings I believe it was. Question for some of you senior guys - This is a 2002 with 15K miles on it. If it were you would you change piston rings at this time? I had no problems in that dept but I seem to get varying opinions to those I talk to. I know I have to hone cylinders. I don not intend to make the bore bigger.
 

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15,000 miles ain't much, the rings should be in pretty good shape....
So what I'd ask ...is how long do you plan on keeping the bike? How many miles do you expect to put on the the thing?

New rings will give you an basicly a new motor you'll need to break in again. If you plan on logging up a lot of miles and keeping the bike a long time, I'd go ahead and do it.
But if you only put on 2-4,000 miles a year, or can foresee selling the bike down the road, seems like a waste of money and time. JMHO
 
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