upgrade the top end

Discussion in 'Performance Mods' started by Street Ryderz, Jan 7, 2017.

  1. Street Ryderz

    Street Ryderz Active Member

    So as many of you know both of these kits will fit the bottom end of our engine with a spacer plate between the block and cylinder! As I was doing my research and looked at the dyno graphs the specs for the mxs sport say it can make 16hp @ 11,500 then the write up for the stage 6 sport says it can make 17hp but when I looked at the dyno graphs it shows that it only makes 8hp @9,500 but then I noticed that the info on top of the graph says it is for the 50cc sport version!So that is very respectable output for a 50cc and in a very suitable rpm range for our needs as a street set up!My problem is I cannot find the proper dyno graph for the 70cc version from stage 6 has any of you come across this and if so can you post it please and thank you! mxs-kit-cylindre-70cc-sport-axe-de-10mm-mxs31446476_courbepuissance.jpg cylindre-culasse-stage6-50cc-sport-mbk-booster-stunt-s6-7115100_courbepuissance.jpg
     

  2. jaguar

    jaguar Well-Known Member

    so are you going to get one?
     
  3. FurryOnTheInside

    FurryOnTheInside Active Member

    "...these kits will fit the bottom end of our engine..."

    How much power can the clutch handle before it just slips and burns?
     
  4. Street Ryderz

    Street Ryderz Active Member

    Yes I'm going to build one but I want to use the stage 6 70cc mk 2 as its cylinder is nikisil treated and the port area at the bottom of intake isnt as deep as the mxs sport 70cc so less cutting of the case under intake!
     
  5. Street Ryderz

    Street Ryderz Active Member

    More spring tension will have to be used and rolling on the throttle but that,s fine,Sean at appollo racing has been running the mxs 70cc top end for a while now and it seems to handle it ok!semi metalic brake pads can be used as clutch pads for improved friction.
     
    FurryOnTheInside likes this.
  6. Steve Best

    Steve Best Active Member

    I apologize guys, I have a Minarelli 50cc nearly ready to go but have been swamped with work and SAR this fall. Winter has hit and biking is out of the question now. Thinking of building a test stand / dyno for bench testing in the garage, but my time is limited. I'm supposed to be semi-retired but work keeps finding me.

    [​IMG]
     
  7. Street Ryderz

    Street Ryderz Active Member

    Steve do you think that where the cut out under the intake is in the spacer(adapter)plate could be ramped to reduce cutting so close to the case bolt!
     

    Attached Files:

  8. Steve Best

    Steve Best Active Member

    Here is what mine looks like while it was being made:
    [​IMG]
    It is cut on the bottom to mate with the Grubee engine, on the top to mate with the Minarelli.
    You can see the "under the intake" port is drilled in preparation for ramping.
    I did not cut the case in this area, and there is no port there in the Grubee, so it ramps.
    [​IMG]

    I have another camera now so I'll try to get more pictures.
     
  9. Street Ryderz

    Street Ryderz Active Member

    cool thanks! I was looking at how much Sean from apollo cut out and it seemed like it could be cut in on an angle so as not to have to relocate the case bolt and yes sorry the intake transfer lol!
     

    Attached Files:

  10. Frankenstein

    Frankenstein Active Member

    Anyone know if a eton viper cylinder can fit on the lower half of our motors? Normally a 90cc motor.
     
  11. Street Ryderz

    Street Ryderz Active Member

    Thats a case reed cylinder that uses wider stud spacing and the stroke is longer so pretty hard to do!
     
  12. Frankenstein

    Frankenstein Active Member

    Hey what is the stud spacing anyway I never bothered to measure and I'm still too lazy to do it now.
     
  13. Street Ryderz

    Street Ryderz Active Member

    45mm for the 66cc I forget what the 48 is but 40mm comes to mind!
     
  14. Frankenstein

    Frankenstein Active Member

    And that's a perimeter measure not diagonal across the bore right?
     
  15. Street Ryderz

    Street Ryderz Active Member

    R
    Right!
     
  16. Frankenstein

    Frankenstein Active Member

    Hmm, that's... Tiny.
     
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