Engine failure

Discussion in '1st & 2nd Generation 1983-1989' started by Wands434, Aug 15, 2016.

  1. Wands434

    Wands434 New Member

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    86 vf500f

    So I was cruising along, 95mph or so and started to climb a hill and no power. Felt like it was running out of fuel so I clicked it to reserve and waited for it to pick up and nothing. I look back and I am rolling massive amounts of smoke. I pulled over and shut it down it continued to smoke for 20 min. Smelt of severely burnt oil. No knocking and temp was normal.

    So I believe I lost a valve seal. There was oil leaking from front left header pipe

    Can valve seals be done from above without pulling the head?

    [​IMG]
     
  2. jeremyr62

    jeremyr62 New Member

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    That's not good. These do fail by dropping valves but I expect you know that. I would check you have compression in all four cylinders. A valve seal going might give you those symptoms but tbh it sounds more serious.

    To answer your question, yes they can but is difficult. You have to stop the valve falling into the cylinder. Filling the combustion chamber with string is one way. Using a continuous flow of compressed air is another. If it is a seal I think you might be better off taking the head off.
     
  3. Wands434

    Wands434 New Member

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    I don't think the valve dropped. At idle it sounds normal all the way to 6k the. Gets boggy above that. I got in late last night and then to work this morning, but I'll do a compression test after work and see what it says. I'm a bit nervous to pull the head seams like a complex motor.


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  4. jeremyr62

    jeremyr62 New Member

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    The plug condition will tell you lots. It is a bit complex but not that different to most multi cylinder bikes. You will need a proper service manual for sure if it comes to that.
    If you are leaking oil at the header then it has to be valve related or rings, or you've holed a piston. Hoping for a cheap and easy fix for you.
     
  5. GreyVF750F

    GreyVF750F Member

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    It could be a number of things. Not the valve seal. Even if you take the valve seal out it would never pass that much oil. Could be a head gasket between cylinder and oil return hole, broken ring etc.

    You sure oil isn't running down from valve cover above the header pipe? There's no other place for oil to come from unless the head has a crack in that area. At first I thought you might have a K&N oil filter on and it blew like a lot of them are doing.
     
  6. Wands434

    Wands434 New Member

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    Oil looked to be coming out of the bottom side of flange where header meets head. Not wet above. I guess it really doesent take much oil inside of hot exhaust to create a ton of smoke.

    When I get back to the shop I'm going to do a compression check and check out the plugs.

    My biggest fear of pulling head is setting timing. I just got the bike and could really live without a 800-1000$ repair Bill.

    My local Honda dealer has a worse reputation than a 5$hr mechanic you find on Craigslist and is currently going under. I called 2 other shops and there not vary enthusiastic. The one shop that said to bring it in, failed to set proper timing on a buddy's gold wing and I ended up doing it. It was off 2 teeth on belt each side. Maybe it was a fluke maybe not.

    Do I have to pull motor to pull the head.


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  7. jeremyr62

    jeremyr62 New Member

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    Unless you have access to a really good mechanic you have to work on these bikes yourself. They are fragile and need TLC consistent with ownership. Just the way it is.
    You don't have to pull the motor to pull the heads but I think most do.
     
  8. Wands434

    Wands434 New Member

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    [​IMG]

    Is there a difference in 500's


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  9. Hellapet

    Hellapet New Member

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    I could not figure this out myself. Probably has to do with the 1986 update but who knows. Someone on here?

    Sad to see this bike having an issue, I thought you got a steal on it and was hoping the best.
     
  10. Allyance

    Allyance Insider

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    I have always gone by the 'F' designation, for my 83 it is VF750F, for yours it would be VF500F. Not sure what the extra A & AC mean, VF750C were the Magnas.
     
  11. Arnzinator

    Arnzinator New Member

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    At that time there may have been California only models (AC designation) . I seem to recall my 86 1000R's Honda shop manual covering both. I think the Cali models had extra emissions hardware.
     
  12. jeremyr62

    jeremyr62 New Member

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    If yours is an 86 it will have the half moon cut outs on the cylinder heads. If you have this then there are quite a few differences to the 84/85 models. If the photo in the first post is your bike, you have a genuine 86. If this is not what you are asking, I'll get my coat..
     
  13. Hellapet

    Hellapet New Member

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    He's just asking which parts list to shop from, the one labeled VF500F A or VF500F AC. Where are the half moon cutouts to be found, out of curiosity?
     
  14. NormK

    NormK New Member

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    You have just go the bike, it is a 500 and you are cruising along at 95 mph, sounds like a disaster waiting to happen to me
     
  15. Hellapet

    Hellapet New Member

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    No reason to think the bike can't handle it. Whats the difference between doing 95 on the first day and doing 95 after 6 months on a 30 year old bike? Sounds like OP is a confident mechanic and would make sure the bike was up to snuff before getting on.
     
  16. jeremyr62

    jeremyr62 New Member

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  17. Hellapet

    Hellapet New Member

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  18. jeremyr62

    jeremyr62 New Member

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    Well, the distinction is a bit obscured now by the passage of time. In the UK (where I lived at the time) I think we got the "new" design in 85 so we only had one model year with the "old" design.
    I think the US got two model years with the old design. I could be spouting bs here though. In the end it doesn't matter as the half moons tell all.
     
  19. Wands434

    Wands434 New Member

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    I was just questioning the A and AC desalination I have no question it's not a 86 motor. I'll look when I get back. I'm a heavy wrecker driver started at 730 am and won't get back till 1am so I'm sol.

    The bike is only turning 7500rpm at 95 there's still 6k more to redline. It has 26k on bike.

    Granted it's 30 years old but so isn't everything else I own. Honda quality lasts.

    Granted most of my mechanical abilities are 2 stroke, gas turbines, heavy diesel and diesel 2 strokes.

    I truly feel it's not a large issue. I ordered the valve seals today and a Honda dealer a hour away is getting back to me on a top end gasket kit. They can get a complete gasket kit 280$ in 3 days but there looking for top only for me.

    I'm going for the gold I guess I'll do the top end. I was planning on doing it this winter anyhow, I open up every motor I buy. But wanted to get the rest of the season out of it.


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  20. Wands434

    Wands434 New Member

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    I'm going to drop the motor from frame most likely, anything out of the ordinary I should know, any tips or tricks.

    My oil pan is leaking just a little from what I seen its a pain and easier when pulled.


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