Vtr250/mc20 spada valves into 86 vf500f engine

Discussion in '1st & 2nd Generation 1983-1989' started by jrodrims27, Nov 23, 2016.

  1. jrodrims27

    jrodrims27 New Member

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    Hey VF500F fans (if there are any left). My idea for new VALVE springs for my old, low mileage 84 engine worked well...but for only about 1500 miles and then it dropped a valve.
    Everything was great, all the valves looked perfect, adjusted to specs. Only 3 were slightly damaged and I replaced those with new ones. THEN one of my original, great looking valves broke right at the cotter groove and ruined my engine. Anyway, after a whole bunch of profanity and aggravation, I dusted off my spare 86 engine and I purchased all new valves. All of them. I even found a brand new front head on ebay for it and threw that on. The part numbers for the valves on an 86 engine are the same as the MC20 Spada/VTR250. I installed those with the springs I had bought for the 84 along with all new cotters and retainers and it's running very, very well with the 84 carbs.

    Just in case anyone was still wondering if it's possible to use VTR250 valves, it is on the 86 engine. Not that VTR250 valves should be any more plentiful for any reason, they're the same as the 86. However, I found a place in Japan selling them on ebay for the VTR250 in decent quantities. According to CMS NL, these actually fit a 2009 European version of the VTR 250 also... These were advertised however for the older 1989/1990 VTR250. I guess it might be possible to use these for the 84/85 because the exhaust valves are the same as the 86 but I have no idea at all if the different part number intake valves are different in dimensions. I'll post some pictures of the 86 engine in my 84 bike as soon as I get my plastics all back on. These engines are very old now and those valves do break, after all, they have been under tension for 30+ years and when they do break and drop into the combustion chamber, it's catastrophic to the engine, your morale and your wallet. I had been thinking...it'll never happen to me especially with my brand new springs right?? Well, wrong! I can't recommend installing new springs on used valves this old as a solution for added longevity. Good luck to all, God knows we most definitely need it.

    Oh! One more thing! The 84 exhaust fits perfectly on the 86 engine with the larger oil pan. I foolishly bought a complete 86 exhaust thinking it was somehow different due to the enlarged oil pan. Wrong! Waste of money! Exhaust is the same for 84 through 86. Are the 86 heads wider than the 84/85? Look at the picture, of course they are so you can't interchange cams or valve covers.

    So there it is.... before- everything great, disaster, 86 engine installed, everything is great again until...? We'll see. Speedo and Tach needles POINTING STRAIGHT up pic included. Youtube running 86 ENGINE (kinda boring) too.
    IMG_20151205_093555.jpg IMG_20161008_132017.jpg IMG_20161127_095656.jpg IMG_20161127_095617.jpg IMG_20170206_115914.jpg IMG_20170206_115859.jpg Untitled.jpg IMG_20170212_130958.jpg IMG_20170212_130958.jpg

    https://youtu.be/A0SukgXfQlo
     
    Last edited: Mar 2, 2017
  2. Wands434

    Wands434 New Member

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    I wish u the best. I love my 86 500 but after one motor down and the replacement one running a little off. I may have lost faith. Cr500 motor next. If the current motor quits.


    Sent from my iPhone using Tapatalk
     
  3. jeremyr62

    jeremyr62 New Member

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    I think it was some of the aftermarket pipes for the 84/85 that didn't fit the 86. I bought a very cheap Laser 4-1 pipe for my 86 but have yet to fit it. (I am not sure it even will fit but I can always bodge it).

    Want to make sure I have the skills to set the carbs up for it first. Don't want it running too lean for obvious reasons.
     
  4. jrodrims27

    jrodrims27 New Member

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    Maybe someday, there'll be a practical, viable electric conversion or something like that. I've only seen a couple of different engines fitted into the VF500F frame but both bikes were in really rough shape already. It could be a bunch of fun to try it. Imagine that! Riding a VF500F with a reliable, maybe slightly more powerful engine?....wow.
     
    Last edited: Nov 27, 2016

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