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Mazzmo Engineering - XJ650 Project

Discussion in 'XJ DIY How-To Videos' started by DaygloDavid, Oct 10, 2020.

  1. DaygloDavid

    DaygloDavid New Member

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    Whilst searching for XJ650 exhausts, came across a series of videos where Mazzmo Engineering do a project on an XJ650 including an 820cc "Big-Bore" engine.

    Here is the first of the series of videos,

    If you've got the time, IMO, they are all well worth viewing.
     
  2. k-moe

    k-moe Pie, Bacon, Bourbon. Moderator Premium Member

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    big bore = big vibraton.
    Better to swap in an XJ 900 engine IMO.
     
  3. JBurch

    JBurch Active Member

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    You could always have it balanced
     
  4. dkavanagh

    dkavanagh Well-Known Member Premium Member

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    I found those a while ago and now he stops by here from time to time. He does some really nice work!
     
  5. k-moe

    k-moe Pie, Bacon, Bourbon. Moderator Premium Member

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    Which would require welding blobs to the crank weights, and a a number of reiterations. Fiddly, and expesive if done by a shop. Still fiddly if done in-house.
     
  6. Minimutly

    Minimutly Active Member

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    Putting bigger pistons in a 4 inline does not require a rebalance, provided the pistons and rods all weigh the same. Will likely make less power than a 900 though, and given the 900 is the same physical size....
     
  7. k-moe

    k-moe Pie, Bacon, Bourbon. Moderator Premium Member

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    That's the key. And in this case they don't weigh the same. Everyone who I've contacted that used any of the big-bore kits for the XJ series had increased vibration afterwards.
     
  8. Minimutly

    Minimutly Active Member

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    Sorry, I meant all the replacement rods and pistons weigh the same. Balancing the crank wont change anything. Adding weight to it to compensate for heavier pistons - why would you?
     
  9. Mezzmo

    Mezzmo Member

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    Hi Guys,
    There is no vibration issue with my engine. I have used a stock 750 crank, rods and barrels with a set of pistons. Check the video below on how I balance rods and pistons. Its really no different for any set of pistons. Generally there are pretty close anyway...
     
    Kweb1889 and Franz like this.
  10. k-moe

    k-moe Pie, Bacon, Bourbon. Moderator Premium Member

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    I would not assume so given the reports I've read about the aftermarket big-bore kits thus far. Yamaha pistons and custom-made (not from a kit provider) pistons are another matter.
     
  11. Kweb1889

    Kweb1889 Member

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    I loved your videos they were full of useful info and I also bought a sand blaster and soda blasted my stuff to clean it and it worked great.
     
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