Fitting a VF500 1986 engine in a VF500 1984/85 frame

Discussion in '1st & 2nd Generation 1983-1989' started by jeremyr62, Mar 24, 2017.

  1. jeremyr62

    jeremyr62 New Member

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    This is a new thread about the 84/85 VF500 bike I purchased in this thread
    http://vfrworld.com/forums/showthread.php/52750-Possible-VF500-purchase

    The engine has a rattle and I have just taken the rear camcover off and discovered this. Probably not the cause of the rattle but enough to make me want to swap out the engine.
    DSC_0071_s.jpg

    I am not too bothered as I have other engines. However these are all 86 engines with the Honda modifications. The difference in the engines that gives me a slight wobble is this one.

    DSC_0069.jpg

    I looked at the frame and I reckon the engine will fit.
    I am sure this must have been done before. Can anyone confirm that the later engine will fit in the earlier frame?

    Edit: The rear cam cover from the 86 will fit onto the 84 engine when it's in the frame so I expect the 86 engine will fit OK.
     
    Last edited: Mar 25, 2017
  2. Captain 80s

    Captain 80s Member

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    85 and 86 frames are identical. 84 had welded upper cowl mounts on the side. 85 & 86 were bolt on so they could be replaced if crash damaged.

    Oh and 84 frames had a service bulletin to drill an extra drain hole in the frame to prevent water from freezing and expanding the rectangular frame under the engine.
     
  3. jeremyr62

    jeremyr62 New Member

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    Thanks for that.
    You learn something new every day. Mine has the welded brackets; never realised that was changed.
     
  4. Mind_Surfer

    Mind_Surfer New Member

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    Jeremy, I am not sure if this helps, but I have a 1984 engine in a 1986 frame. Did the swap thirty years ago, so don't recall much detail other than the coolant piping on the '86 is larger diameter IIRC.
     
  5. jeremyr62

    jeremyr62 New Member

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    I was just a bit concerned the wider cylinder heads of the 86 might foul on the 84 frame but this doesn't seem to be the case. So it all systems go for the engine swap.

    Did you ever tell why you had to swap engines?
     
  6. Mind_Surfer

    Mind_Surfer New Member

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    Yes, dropped a valve at high rpm.

    Sent from my XT1031 using Tapatalk
     
  7. jrodrims27

    jrodrims27 New Member

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    of course it fits, it's what I'm running...an 86 engine in an 84 bike. The heads and valve covers are wider so it's a tighter fit, getting the back valve cover on can be a little tight. I took the valve covers off to fit the engine in and then had to remove the back left bolted tabs inside the valve cover. I don't really know what those are for but it makes taking it off and putting it back on for valve checking purposes possible because otherwise, I couldn't get the damn thing off, no room. Maybe you'll have better luck.

    valve cover.jpg IMG_20161127_095617.jpg

    https://www.youtube.com/watch?v=A0SukgXfQlo&feature=youtu.be IMG_20170212_130958.jpg
     
    Last edited: Mar 29, 2017
  8. jrodrims27

    jrodrims27 New Member

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    Hey mind,

    You dropped a valve 30 years ago? On a relatively new engine/bike? wow... that's the kind of luck that I'm accustomed to.
     
  9. Mind_Surfer

    Mind_Surfer New Member

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    Jrod, it was still under the 12 month warranty. Denied of course, citing abuse & neglect. Hehe

    Sent from my XT1031 using Tapatalk
     
  10. jeremyr62

    jeremyr62 New Member

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    I have fitted 86 engines back into 86 frames and had no trouble. I have no trouble taking off the rear head covers either. Your experience suggests maybe the frames are not the same after all. Anyway, I am sure I'll manage one way or the other.

    If the VF500F engine turns out OK otherwise I might get a set of exhaust cams off Ebay for it. I find it hard to scrap stuff.
     
  11. jrodrims27

    jrodrims27 New Member

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    hey Jeremy,

    The 86 engine did indeed fit my 84 frame but the back valve cover is very close to the frame on the left side, maybe about 1/4 to 1/2 inch gap at best.

    Fitting used cams on different used rockers probably won't last you very long. Not to mention putting different used cams into the already worn cam bearings/caps isn't the best thing to do. You should probably check the condition of your rockers for divots before going that route. From what I've read, the relatively poor quality steel in the cams many times have gaps/holes right below the coating that show up with minimal wear. If you have another complete good engine sitting around, you'd probably be much better off with that and keep the damaged cam engine (with unknown noises) aside just for parts. The headaches with that one could be endless for you. Good luck pal.
     
  12. jeremyr62

    jeremyr62 New Member

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    You are probably right. I have two bikes, two really good 86 engines, a very iffy 86 engine which is definitely just for parts and now the 84 engine. I wont be spending anything on the 84 engine until I have had the cams out and then only if it looks like it could be a runner.
     
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