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Discussion Starter · #1 ·
Hello all,

So i recently purchased my 90 vulcan 750 two weeks ago. everything ran great up until the other day. a large knocking noise was coming around the oil fill area. (this is my first bike and i am new bike motors). I rode it to my friends house in hopes he could check it out and see what that noise is. when i was down the street from his house, the oil light came on. so i made it to his house, we looked at it, and it just looked a bit low on oil. long story short, i (stupidly) tried to make it home and roughly a mile after i leave, the motor dies on me while going 30ish mph and i come skidding to a stop. once it cooled, i was able to get it started again but i had to keep it around 2 rpm to stay on. i'm thinking the worst... i drained the oil last night and there are aluminum shavings in it. one thing i didnt remember pulling out was the oil screen, so this AM i peer into the hole and see the screen deep in the hole. I was able to fish it out, and the screen is all cut up and abused.

What are your thoughts on this? do you think i did some major damage? or perhaps i am very lucky and i can just buy a new screen, put new oil, and see how it goes?
 

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Was the bike making the loud knocking noise when you tried to ride it home?

Aluminum bits in the oil... Sounds like a rod bearing went out.

Not a good thing. If its still making noise....DO NOT ride the bike until someone looks at it.

How did your oil get low? Does it leak oil?
 

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Hello all,

So i recently purchased my 90 vulcan 750 two weeks ago. everything ran great up until the other day. a large knocking noise was coming around the oil fill area. (this is my first bike and i am new bike motors). I rode it to my friends house in hopes he could check it out and see what that noise is. when i was down the street from his house, the oil light came on. so i made it to his house, we looked at it, and it just looked a bit low on oil. long story short, i (stupidly) tried to make it home and roughly a mile after i leave, the motor dies on me while going 30ish mph and i come skidding to a stop. once it cooled, i was able to get it started again but i had to keep it around 2 rpm to stay on. i'm thinking the worst... i drained the oil last night and there are aluminum shavings in it. one thing i didnt remember pulling out was the oil screen, so this AM i peer into the hole and see the screen deep in the hole. I was able to fish it out, and the screen is all cut up and abused.

What are your thoughts on this? do you think i did some major damage? or perhaps i am very lucky and i can just buy a new screen, put new oil, and see how it goes?
You "could just buy a new screen, put new oil (in), and see how it goes" but I doubt that you will ride very far in that condition. There has to be a reason for the oil to disappear, the shavings to suddenly appear and screen to get sucked inside. The screen is suppose to collect all the shavings (very minimal) due to normal engine wear from circulating around in the motor. You need to know where the shaving came from and why before you go any further. The screen may have been installed wrong but I doubt that as it is a pretty straight forward setup. I would say since the motor did restart you may have a chance of saving it without too much of a problem but you do need to not run it anymore unless you are just looking to destroy it completely.
 

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Discussion Starter · #4 ·
Yes it was still making the noise. i put a magnet to the shavings and it didnt stick, so thats why im assuming its aluminum. Could the shavings have just been from the oil screen? its cut up pretty bad. i am already prepared to pull the motor, i already have part of the bike disassembled. after i started it the last time to make sure it wasnt seized, i've kept it off. i think it had enough oil, but it was just so black that i couldnt see if the fill window was just tinted or something. it looks like it does not leak a drop of oil
 

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Discussion Starter · #5 ·
It did seem that the person installed it incorrectly. i pulled out the plug as follows... drain plug, spring, washers, THEN fished out the screen
 

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yea that screen has seen better days.

magnet picked up the metal particles you say?? then they are NOT aluminum.

was it vibrating badly while running? (not just the noise, but shaking)?. maybe the dampers are going/gone. that could cause metal shavings in the oil/screen.
 

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yea that screen has seen better days.

magnet picked up the metal particles you say?? then they are NOT aluminum.

was it vibrating badly while running? (not just the noise, but shaking)?. maybe the dampers are going/gone. that could cause metal shavings in the oil/screen.
That would be a good outcome. No Case Splitting !
Dampers = $40.00+

:smiley_th
 

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Just a thought: could be balance dampeners doing the beating. BUT, wondering though if someone did the stator mod and let the engine fill with heavy shavings from cutting to fast and that stopped the screen enough until the pump sucked it flat. If so it could have torn at the screens oil passage end and now the filter or pump is stopped up, and the rod may be knocking from the oil starvation.
 

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Discussion Starter · #10 ·
Yeah initially when I put the magnet through the oil on my pan, it didn't pick up, but when I put it against the screen it was hitting the magnet. Do you think the screen or dampers would have caused the loud knocking noise and the oil light to come on? I know only me opening this bad boy up will give me the true story. I have ordered a manual and I'm hoping to get it by Friday so that I can disconnect everything I need to to pull the motor. Is there anything you all would recommend I replace while I have it out? Everything looks original except for a replaced petcock.
 

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Discussion Starter · #11 ·
Oh yeah, and about the vibration... I didn't so much notice an increased level of vibration, but I think my focus was on the loud knocking noise!
 

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Discussion Starter · #13 ·
I've unfortunately accepted that the motor must be pulled. Haha. I will keep you all updated once I pull this out and start taking things apart to assess the damage! Thank you for the feedback
 

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I really can't see how the screen got sucked into the engine. It won't physically fit. There is a spring behind it, so it is supposed to have pressure on it. Having the oil pressure light come on is not a good thing. Engines don't live very long without oil pressure. Loss of oil pressure could have been caused by a plugged up screen, or if you have a bad bearing, you could be losing oil pressure there. I would remove the flat cover on the left side of the engine, the one with three screws. HOPEFULLY, you won't find that someone hacked up the stator cover. If they did, and with all the bits of metal you found, things don't look good. If it is cut up, then I would go back to whoever you bought it from and confront them with it. If you can get them to admit it, demand your money back.

Unfortunately there is a procedure that has been used by many boneheads lately to replace the stator without pulling the engine. It involves cutting out the front of the stator cover, so the stator can be removed and replaced without removing the cover. I have the cover off mine right now, and it is obvious that there is no possible way you can do this without getting metal shavings inside the engine. I figured it was no big deal, as they were only damaging their own bikes. But if someone buggered up their bike, then sold it to an unsuspecting buyer without telling them, then it becomes a whole nother matter.

If the stator cover is not cut up, then the most likely issues would be a bad bearing (though it seems like you have more metal particles than a bad bearing would cause) or a balancer gear chewing into the case. Either way, I would not hold out to much hope for that engine. Most likely you only found a small part of the shavings, the rest are scattered around throughout the engine (remove the oil filter and cut it open) That, plus riding it without oil pressure, likely caused more damage than it would be worth it to fix. You could go ahead and tear it down and see how much damage there is.

There is a manual you can download from this site. I also have the Clymer manual, which I like better. Also check out Roaches videos. He did an excellent job. Even better than a manual.
 

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It didn't get sucked into the engine. It is collapsed and torn and still covered in shavings if I read his post correctly. But most of all, looking at the screen I have laying here in front of me, that screen is gummed up pretty bad which would restrict the oil flow and with the vacuum of the oil pump it would collapse.
 

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Discussion Starter · #16 ·
Thanks for the info guys, once I open this thing up, I'll get a good idea of the damage done. If I need to search for another motor, what years are interchangeable for my 90 Vulcan? Any of the years?
 

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All years are interchangeable. Before you pull out the engine, could you remove the left side 3 screw cover? I'd like to see what is behind it.
 

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Discussion Starter · #18 ·
That thing is on there really tight... When I wake up I'm going to take another stab at it, but when I tried to get it off with an impact screwdriver before I left for work, it wasn't nudging. I'll keep you updated
 

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I ended up using a screwdriver bit in a socket (so I could put some of my 280 lbs behind it to hold the bit into the screw) to get mine to break loose, yea they can be stuck!

also, I believe them are P3 sized, not P2.. use the right sized screwdriver tip on them
 

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All of what look like Phillips screws on Japanese bikes are actually JIS "Japanese Industrial Standard" They look close, but a Phillips screwdriver or bit does not fit properly, and can strip the screw. I usually grab one of those screwdriver bits from my large box of oem tool kits that come with new bikes, clamp it in a pair of ViseGrips at a right angle, and use it like a socket.
 
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