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Thread: Bonneville Pistons for Chief?

  1. #1
    Join Date
    Nov 2009
    Posts
    199

    Default Bonneville Pistons for Chief?

    Does anyone know of a source for Bonneville pistons to fit Chief motors? I'm in need of 2 sets, one set of Std. and +.040 I'd prefer the ones that Jim Sutter was supplying years ago as that's what I used to balance my motor and they are heavy! Rocky has very few left and not the size I need. Trying to build up 3 sets of cylinders for the 24 Chief Cannonball rig.

    Thanks! Gene

  2. #2
    Join Date
    Jul 2001
    Posts
    508

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    Quote Originally Posted by gharper View Post
    Does anyone know of a source for Bonneville pistons to fit Chief motors? I'm in need of 2 sets, one set of Std. and +.040 I'd prefer the ones that Jim Sutter was supplying years ago as that's what I used to balance my motor and they are heavy! Rocky has very few left and not the size I need. Trying to build up 3 sets of cylinders for the 24 Chief Cannonball rig.

    Thanks! Gene
    Gene
    I have several used sets(no rings) of Bonnie pistons if that would help, all from Jim Sutter. the +.040 are on the shelf for my next top end rebuild (soon) sorry not for sale. nobody else is making them as the demand is not big enough.
    Kevin Valentine 13
    EX-Chief Judge

  3. #3

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    I am looking for a set of .020 bonneville pistone

  4. #4

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    46CHF, how do you identify Bonneville pistons as opposed to regular pistons? I have two pair of pistons marked .020. Probably aftermarket. One set has a number on the inside and the other set has JADE on the inside. Is the difference the location of the piston pin?
    Dave

  5. #5

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    Howdy Dave,

    Jade made Chief pistons years ago for which it would appear at the time they used one base casting for all three applications: 74 inch Chief, 74 inch Bonneville Chief and 80 inch Chief. From distant memory (my hot rod 1948 80 inch Bonneville Chief build in 96), wrist pin location was the same across all three, a Bonnie piston is taller than a 74 as there is a relief cast into the head for the piston to portrude into. An 80 inch piston has a shorter skirt to ensure clearance to case baffles on this longer stroke engine.

    At the time, I used Bonnie pistons as they were the only 3 ring piston for a Chief enabling use of modern narrow Mahle rings. I vaguely recall stock 74 and 80 inch pistons had a crown thickness of about 145 thou. This was my reference point for machining the thick crowns off the Bonnie’s down to about 150 to 155 thou for higher compression. I then trimmed the skirts to fit this 80. With cams it took all of my 230lbs on an extended 53 Chief kicker arm to start this beast, once running, pretty exciting stuff. In my 60’s now, not so exciting, probably going to fit extra thick lazer cut copper head gaskets before Bike Week to tone this thing down a bit.

  6. #6

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    Hi Peter, thanks for the reply. Today I noticed the box the JADE pistons are in has a sticker from Beck-Arnley part number:61 0077. Beck-Arnley quit selling motorcycle parts in 1973 according to their website. They now just sell auto parts. If someone has a Beck-Arnley catalog for motorcycle parts maybe this part number would tell me what I have. The overall height is 3.250, same as the bore. Dave

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