yamaha blaster piston hole pls help

Discussion in 'Engine' started by helpblaster, Nov 9, 2019 at 10:54 PM.

  1. helpblaster

    helpblaster Member

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    Screenshot_20191109-214959.png Screenshot_20191109-215143.png Screenshot_20191109-215015.png Screenshot_20191109-215054.png bought a brand new piston and cylinder off ebay. i was running it for about 2 hrs and it stop. no compression at all i took it apart and piston had a hole my spark plug on top of the tip was broken.
    i have a LRD exhaust and pipe Mikuni carburetor main jet was 230 what should i do next pls help do i need a 280 main jet ? here some pictures...also a picture what kind 2stroke oil i used
     
  2. helpblaster

    helpblaster Member

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    here picture of my pipe
     

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  3. Slydog

    Slydog New Member

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    230 is the stock jet i believe.you would definitely need to jet up for that pipe.maybe someone running that pipe would know the jet size to start with.that oil is questionable.this thing is air cooled
     
  4. Slydog

    Slydog New Member

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    Any pieces in the crank area?hows the rod look?
     
  5. Awk08

    Awk08 Administrator Staff Member Technician

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    LRD pipes require at least a 300 main jet, the one I had liked a 330 main here @ 1800' elevation in summer temps
    lower elevation and lower temps will require more fuel/richer jetting
    I'd buy 300 thru 350 mains, start large and plug chop down

    stock jetting with an aftermarket pipe, ebay cylinder with unknown piston to cylinder specs or ports chamfered ?
    and cheapest 2 stoke oil around, is a recipe for melting pistons :(

    If you still have the factory cylinder, just have it bore/honed to a new piston, by a reputable shop
    up that main jetting to match your pipe or other airflow mods, using plug chops to determine that
    and stop wasting $ on chi-wanese junk, sad but true :(

    plug chops
    https://www.blasterforum.com/threads/how-to-plug-chop.53237/

    Chi-wanese Paper Weights :(
    https://www.blasterforum.com/threads/oh-no-dont-use-cheap-chineese-parts.72185/
    https://www.blasterforum.com/threads/more-info-on-the-chinese-blaster-cylinder.66076/
     
  6. Slydog

    Slydog New Member

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    Awk is 100% right roll with it.is the crank small end discolored
     
  7. helpblaster

    helpblaster Member

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    rod look good no up and down.. i only have little play side to side
     
  8. helpblaster

    helpblaster Member

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    update i installed another ebay piston and new spark plug and change main jet 300 for about 4 hr later my spark plug burn down again.. not sure what to do anymore maybe i need good brand 2stroke oil or something.
     
  9. helpblaster

    helpblaster Member

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    i did i put in a brand new ebay carburetor
     
    Last edited: Nov 10, 2019 at 8:55 PM
  10. Slydog

    Slydog New Member

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    Do you still have your oem parts?they are far superior to the Chinese junk
    I believe awk said 300 thru 350 mains.you did do a leakdown test before starting hopefully.did you start with the 350 jet and check plug?lean is mean but not for long
     
  11. helpblaster

    helpblaster Member

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    i installed a new piston and new spark plug and change my main jet to 300 and my spark park blow up.. i think its the 2stroke oil
     
  12. Slydog

    Slydog New Member

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    You should read up on jetting and plug chops.you need to take your time and get the jetting right.leakdown test the engine for air leaks.heat cycle engine and retouqe.buy a 4 pack of plugs or more.you have to fix your lean condition or change piston every time you ride
     
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  13. DKavcak

    DKavcak New Member

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    There could be a multitude of things going on here. I'm going to list a few of what I think is going on:
    • It's entirely possible you had slag and burrs from your jug ports/cylinder ports/piston skirt break off. These Chinese pistons don't exactly have the quality control that the "big guys" have, so you have to kind of go over everything with a magnifying glass to rectify it.
    • Your jetting was VERY lean. With any aftermarket exhaust, I think the leanest jetting I've seen was my buddy's Blaster, and that had a 260 main jet. It runs like utter garbage at 1000 to 1500 ft. above sea level. Try to run a 280 main at the bare minimum.
    • The two-stroke oil you're using may not have the lubricating properties of something like Amsoil, Klotz, Yamalube, Bel-Ray, etc. I've used Quicksilver, which is a cheap Autozone brand, on my YZ250 for a long time with no issues.
    • In addition to the oil properties, depending on how you get oil into the combustion chamber, your oil pump may have bombed, thus causing a lack of "cooling" lubrication. Two-strokes are funny, where you can run it with just gas, since that's what ignites and runs the damn things, but you can't run it on just oil. The oil is mainly there for lubrication and cooling.
     
  14. Slydog

    Slydog New Member

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    Are you premixing 32:1?
     
  15. helpblaster

    helpblaster Member

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    thanks for the help i traded both of my yamaha blaster for a kawasaki 220r 2stroke
     
  16. helpblaster

    helpblaster Member

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    thank you for helping this noob out thanks again <3
     
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  17. DKavcak

    DKavcak New Member

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    Hell yeah! KDX's rock! I've always wanted one. They're the best woods bike in my opinion, hands down.
     
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  18. Slydog

    Slydog New Member

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    Blaster 1 exblaster owner 0. Blaster wins
     
  19. helpblaster

    helpblaster Member

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    here picture of my new bike
     

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  20. Slydog

    Slydog New Member

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    Nice trail bike.looks clean.i have a kx. And a yz. Besides the blaster.
     

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