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Powroll pistons

cyclebuster

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I have a set of Powroll 10041 part number high dome pistons said to be an 836 kit for a CB750. Has anyone ever seen this number?
 
Dont know about that number but there is a set of Powroll pistons for the 750 on ebay right now.
 
I have a set of powroll pistons that has 10040 on them. Does anyone know where the specs for them might be obtained?
Would like to find bore clearance specs and comp.ratios. any info will be appreciated
 
More than likely they are 65mm which is an 836cc. If you can get some pictures we might be able to determine the compression ration from the dome shape. Are you looking at doing a build with these?
 
Going through my stuff i found the correctly bored cylinder set for these pistons. All I need now is some rings, and a gasket set. I have a high performance camshaft, and a ported cylinder head here, so I hope to put it all together soon
 
They are 65mm pistons.will take a pic as soon as i get over to my shop. Would really like to find specs on bore clearances.can stock sleeves be bored to 65mm without problems?
 
mine are. well they look stock anyway. being NOS in old packing I am missing 4 teflon pin end sliders. anyone have some?
 
Yup 65mm is the common 836cc no problems with stock sleeves. Any 836cc gaskets will work, I like Cometic brand. Finding rings for these pistons may be the problem with your build. I read on sohc4 forum about someone looking for rings for powroll pistons and they never found them. But for your information I have some 970cc pistons and was looking for rings and contacted Total Seal and they could make me a set for $145. The problem is the Powroll pistons are a cheaper cast piston and dont know if they are worth the money of having custom rings made. May want to look into new Wisco or Cycle x pistons. PM me if you want to go more in depth, I would like to hear more about your build. Got some pictures of your head? What cam are you going to run?
 
Thank you, the rings on the pistons only have a couple hundred miles on them. I was thinking with a fresh bore and hone they may reseat ok. Just gathering parts for an engine build right now. Currently putting together a XS650 for the wife. Have to finish that project first. My 750 runs great now,just toying with the idea right now. Have had these pistons in storage for over 25 years, waiting for my stocker to wear out, don't know if i will ever wear it out
 
I guess it is possible the rings may seat with a fresh hone in the cylinders. I have never tried used rings because I dont want the hassle of having to take it apart if it doesn't work. Still need to determine your compression, they had 10.5 and 12.5 ratios or there abouts.
 
The motor they came out of wasnt run enough to even break in when he crashes the bike and it got parted out. The rings are like brand new as is the pistons. I have talked to guys that build race motors for cars and didnt think there should be any problems in sealing as long as the proper end gap is obtained. I am guessing they are the 12:5 to 1 pistons by the size of the dome on then. Will post a pic
ASAP. It seems powroll is going through difficult times,not sure if they are still in business.
 
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