17 replies to this topic

[Guess-Works.com]

std stroke for 1275 is 81.28mm ( or near as damb 81.3 )

Well... 3.2" to be more precise...

But.. Dan's also got a point that in the early workshop manuals it's defined as 3.2" or 81.33mm.... think someone got their slide rule cocked up when workig that out

Edited by GuessWorks, 22 May 2007 - 10:51 AM.

[GraemeC]

0.1mm of stroke isn't going to make that much differnece though! Its changes Guesswork's calc from 10.56:1 to 10.57:1

My spreadsheet gives it as 10.64:1 though but it does go to silly decimal places. I would attach the spreadsheet for those interested but apparently I'm not allowed to upload excel files and I really can't be ar$ed to email out to everyone!

Not sure how you get to 9.7 though Dan?

Edited by GraemeC, 22 May 2007 - 10:51 AM.

[danwebster]

LOL no nor me, must have pressed the wrong button on the calc somewhere.

10.5, assuming swept volume is 344.7 given a 73.5mm bore and 81.3mm stroke.