Speedfight carb jetting

Discussion in 'The Workshop' started by Paul Smith, Apr 13, 2021.

  1. Stevep

    Stevep Well-Known Member

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    5,895
  2. Paul Smith

    Paul Smith Member

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    72
    Bugger.... New piston and but no start
     

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  3. Stevep

    Stevep Well-Known Member

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    5,895
    No good
    Barrel as well.........
     
  4. Paul Smith

    Paul Smith Member

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    72
    I re built it again and got a higher compression this time but kind of sounds like the timing is out. Not sure how you check the timing on a 2 stroke?

    I think I'll strip and rebuild from the ground up with all new kit.
     
  5. Paul Smith

    Paul Smith Member

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    72
    Ok, so what could stop fuel getting from the carb to the plug?

    The carb is definitely getting fuel and I've replaced the petal but not convinced the fuel is getting to the plug. I tried easy start and no joy so just wondering how I could test if she would start if I can get it to the plug
     
  6. Stevep

    Stevep Well-Known Member

    Messages:
    5,895
    If it's cranking and the plug is staying dry then the vacuum created by the downstroke of the piston isn't good enough to open the reed petals and suck fuel in.
    The compression needs to be 100psi or above.
     
  7. Paul Smith

    Paul Smith Member

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    72
    Ok cool so I ordered a race crank and have stripped her to bits.

    Just got to work out how I can fit the new bearings in to the casing fit the crank and fit oil seals so they don't leak :-/
     

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  8. Stevep

    Stevep Well-Known Member

    Messages:
    5,895
    Head over to my website
    Streathamautos.Co.Uk
    Click on the blog tab on the upper right, scroll down, you'll see all the info you'll ever need for the speedfights.
     
  9. Paul Smith

    Paul Smith Member

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    72
    That's brilliant thank you I've started watching them. Wish I had seen some of it first .
    When you split the casing a small dowel thing fall out. Can you recall where that came from or goes as mine did the same but can't see anywhere obvious for it lol
     
  10. Stevep

    Stevep Well-Known Member

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    5,895
    It's a locating dowel, there should be two
     
  11. Paul Smith

    Paul Smith Member

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    72
    I have the 2 longer ones that stayed in the casing but this was a short style one. Maybe like a little spacer?
     
  12. Stevep

    Stevep Well-Known Member

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    5,895
    Ah no, not a spacer.
    I just watched the video back.
    That thing that fell out was one of the oil pump nuts.
    They are square nuts that go into a slot in the cases.
     
  13. Paul Smith

    Paul Smith Member

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    72
    The little one on the left? :)
     

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  14. Stevep

    Stevep Well-Known Member

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    5,895
    No, one of these
    [​IMG]
     
  15. Paul Smith

    Paul Smith Member

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    72
    Where does this go?
     

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  16. Paul Smith

    Paul Smith Member

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    72
    Ignore the eBay bit but it's the part I'm not sure where it goes lol. Does it just rest in the starter hole?
     
  17. Stevep

    Stevep Well-Known Member

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    5,895
    Yes goes in the hole furthest to the front of the belt case. Not quite rest in there, but should press in easily.
     
  18. Paul Smith

    Paul Smith Member

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    72
    Slight delay as I had to wait for time off. I have the new bearings in and new crank in new casing, seems stiff to rotate the crank. Hoping after a few rotations it'll free up. Fingers crossed
     

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  19. Stevep

    Stevep Well-Known Member

    Messages:
    5,895
    After the engine halves are together and the bolts torqued down again, tap the crank each way and you should find it loosens up a little.
     
  20. Paul Smith

    Paul Smith Member

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    72
    I hope so :).
    That'll be the first job tomorrow
     

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