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  1. #1
    SonicRA's Avatar
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    Unhappy Is there Life after 86.5mm...?????

    Hey there Crew, hey I have a full riva motor running 86.5mm pistons. Ive just fried the back piston but looking at riva's part listings thats it.... only the one oversize? How can this be surley you get more than one shot at it? Cheers James


  2. #2
    Buaidh No Bas howestek's Avatar
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    Saw R&D 86.5mm at dales jet sports. Special made Wiseco for R&D?

  3. #3
    Moderator OsideBill's Avatar
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    I have 87mm in my 1390 not sure if yours is sleeved or plated but maybe give Lowell a call he can steer you in the right direction on these.

    http://www.greenhulk.net/forums/show...t=piston+sizes

  4. #4
    SonicRA's Avatar
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    Its a sleaved motor, and the 1390 group k pistons are designed for plated not sure if this is an issue? anyone? James

  5. #5
    Moderator OsideBill's Avatar
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    Quote Originally Posted by SonicRA View Post
    Its a sleaved motor, and the 1390 group k pistons are designed for plated not sure if this is an issue? anyone? James
    How is it designed for plating? A piston is a piston. You can go the extra mile and have it coated for better lubricity and thermal bearier. I say as long as you have room to bore and hone to the correct clearances I do not see an issue here. The head may need to be matched for new style piston crown and diameter,

  6. #6
    SonicRA's Avatar
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    Hey no worries then, I just wondered about the material and design of the rings more then the pistons! Cheers anyway!

  7. #7
    YudLuz2's Avatar
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    One of my recent customers had a sleeved 86.5 motor
    and did the same thing. He just bored up to the 87mm
    Group K piston. I did a little fine tunning and with my
    handling package it was hitting right at 81 mph through
    some mild wind chop.

  8. #8
    Moderator OsideBill's Avatar
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    I have an extra sleeved core cylinder if anybody needs one $75

  9. #9
    mrbtd's Avatar
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    Is there only one type of sleeved cylinder ?

    I.E. LA Sleeve,SBT

  10. #10
    No the Miller sleeves are not as big in diameter as some of the sleeeves used by Chapin and Judge. I have cylinders that were Chapin/Judge which probably are Lamey derived that had 90mm sleeves, they are out and the hole is 90mm. The Mel Miller and Speedwerx/Hedlund engines have sleeves around 87-88mm measuring thickness at the transfer roofs where the cast iron meets the aluminum.

    I've also seen one sleeve at 94mm's in a GPR - they used CR500 pistons long before the rage on this forum of big bores.
    Last edited by MTRHEAD; 12-26-2007 at 01:39 PM.

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