1968 cb450k1 engine rebuild question

Grayson

New Member
Ive built a few bikes but never done a full engine rebuild on a bike. I pulled the jugs off my 1968 cb450k1 the otherday and started messuring the cylinders to see of they were within the servicable limit or if i was gonna have to get them bored over (standard - 2.7560) (limit - 2.7600) but i took a ton of measurements and im getting an average of 2.9017 anyone have any suggestions? Can i bore it bigger? Was it bored to 2.9000 and now i just need to find some new pistons to fit this or maybe just new rings if i clean up the existing pistons. Thanks for your help in advance.

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My experience with the 459 is that there are very few OE standard size pistons available. The Service manual should tell you how big the 1 over 2 over 3 over and 4 over sizes are. Typically you get pistons, then have the bore done to match. I suspect there is still room for another bore if needed.
 
TheCoffeeGuy said:
My experience with the 459 is that there are very few OE standard size pistons available. The Service manual should tell you how big the 1 over 2 over 3 over and 4 over sizes are. Typically you get pistons, then have the bore done to match. I suspect there is still room for another bore if needed.
Awesome thanks for the info
edit: it looks like i can overbore to 74mm just wondering if anyone has done this and if there is any issues that is could cause down the lane? im not trying to build a race engine or anything. most of my engine parts ill be replacing with ome parts, I just wanna bring some new life into this old bike and do it properly.

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THR racing will sell you a pair of 74mm pistons that are suited to 93 octane street gas.
 
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