Performance heads

Discussion in 'Performance Mods' started by gary55, Oct 4, 2016.

  1. gary55

    gary55 Active Member

    66 cc engine heads left to right. Stock straight plug head = 10.1cc's. Stock slant plug head = 6cc's. Pancake performance head = 7.9cc's. Round finned performance head = 8cc's. Flat fined performance head = 8cc's. While these performance heads are far better made than a stock head, they won't increase compression unless you are replacing a straight plug head. I am not sure how the squish band effects pre ignition if at all. If it has no effect than there should be no worry of early wrist pin or chrome bore lining failures.
    [​IMG]
     

  2. jaguar

    jaguar Well-Known Member

    where can the 8cc heads be bought?
     
  3. gary55

    gary55 Active Member

    pancake and flat finned head from kings. The flat finned head (far right) is off a GT 80 engine from kings, but they sell them separately. The round finned head was from mzmiamiparts out of Florida.
     
  4. jaguar

    jaguar Well-Known Member

  5. butre

    butre Well-Known Member

  6. jaguar

    jaguar Well-Known Member

    this is fortunate for me because I own a Suzuki AX100 and they sell parts for it. No parts for it are available down here and the main source for its parts in England has a problem using my debit card. So thanks.
    It also brings back memories of the MZ I used to own when I lived in Dallas. It was crummy but free so I rode it till it self destructed the crank.
     
    lazylightning@mail.r likes this.
  7. gary55

    gary55 Active Member

  8. FurryOnTheInside

    FurryOnTheInside Well-Known Member

    I am looking at the Chinese knockoff of the RSE, or at least very similar looking design.
    I'm not a fan of buying knockoff stuff but money to get this engine running has been spent on too many lovely forks and awesome brakes (I just can't help myself!! Haha), and with free shipping from China it's just a lot more affordable in the UK. So I'm just wondering if anyone has any thoughts on this one or has tried it. o_O
    I didn't want to start a new thread for this question.
    If I don't get replies I'll probably just order one anyway. :)
     
    Last edited: Mar 19, 2017
  9. butre

    butre Well-Known Member

    I believe the mzpartsmiami rse type reed is Cuban made, not Chinese. It's not a direct knockoff of the RSE, it's just similar conceptually. there's not much you can do with a bolt on externally mounted low profile billet reed valve
     
  10. Steve Best

    Steve Best Active Member

    The Chinese knockoff of the (mzpartsmiami) RSE head does not duplicate the squish area very well, and will not work as well.
    I have both. It is possible to recut the squish area. The Chinese knockoff of the RSE head is also lighter and slightly less fin area. I don't think that would make much difference in my climate, but maybe in Miami or Arizona?
     
    FurryOnTheInside likes this.
  11. FurryOnTheInside

    FurryOnTheInside Well-Known Member

    Thanks for replying but it isn't the reed I'm referring to, it's the pancake head with the German looking cross shaped top.
    I'll get the genuine RSE reed valve later on and then I will feel less like a bad person who buys rip offs of real MBers hard work. :oops:
     
  12. FurryOnTheInside

    FurryOnTheInside Well-Known Member

    Thank you for your reply. I will try your emery glued to spare piston technique. I had thought it looks like less fin area. As long as no serious malfunction issues this is looking like a sensible option for a UK/European build. :)
     
  13. Steve Best

    Steve Best Active Member

    Sometimes a picture is worth a thousand words:
    [​IMG]

    [​IMG]
     
    FurryOnTheInside likes this.
  14. gary55

    gary55 Active Member

    Re working the stock head as Steve shows is your best option from a economical stand point. It will still have decent compression, and if you dial in the squish gap to the rec
    commended .8mm it will have higher than stock comp.. Probably in the 145 psi area.
    Using the head Steve shows on the right will require a good deal of material removal from the jug or resurfacing the jug to use a teflon tape style gasket. I've herd the tef. tape gasket works well. You will still be left with to wide a squish area without opening up the dome. Too wide being relative as to what one is looking for. You have probably seen the earlier posted perf. results.
    Of the heads below the left head with the fins that converge toward the plug is a 6cc head. It will bolt on with no compression loss over the slant plug head, and has a squish band close in width to what Steve produced at 7.5mm. The other two while having the narrower band are still like the flat head Steve shows in that there volume being 8cc will need the same work to maintain a good compression, i.e. decking jug or tef. tape gasket.
    [​IMG]
    [​IMG]

    So since it's not that hot where you live the only draw back to the stock re worked head is constant re torquing.
     
    Last edited: Mar 20, 2017 at 10:57 AM
    Steve Best and FurryOnTheInside like this.
  15. FurryOnTheInside

    FurryOnTheInside Well-Known Member

    Thanks Gary. You've given me lots of info there to help me get started on this head when it arrives. I have already ordered it. I just don't feel comfortable with going far from home with the stock head having read the disaster stories, and seen the quality of the stock generic non-Grubee head I received. I wanted a way to make the engine more my own anyway. :cool:
    I will be using the twisted Teflon tape gasket anyway. I'll buy a compression tester next month and check cranking pressure and squish clearance. :)
     
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