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68.65 mm bore. Anyone know what pistons?
Posted: Mon Apr 30, 2012 9:37 am
Author: malmojoe
I have a cylinder with 68.6 or 68.7 mm bores - not too good with the vernier. Is this recognisable as a known dia for something? Would be good if I could get some pistons for it.
Cheers
Glyn
Posted: Tue May 01, 2012 2:39 pm
Author: Keefleaf
69mm is 998cc
Measure again
Re: 68.65 mm bore. Anyone know what pistons?
Posted: Tue May 01, 2012 5:08 pm
Author: jimmock
malmojoe wrote:I have a cylinder with 68.6 or 68.7 mm bores - not too good with the vernier. Is this recognisable as a known dia for something? Would be good if I could get some pistons for it.
Cheers
Glyn
Internal mic is what you really need.
Jimmock.
Posted: Tue May 01, 2012 5:36 pm
Author: malmojoe
could be 69mm. calipers are cheapest chinese from fleabay. Where can you get 69mm pistons from now? All I can find is 70mm ones.
just another question, the measurement of a bore referes to the bore doesn't it? 66mm bore on a standard bike is 66mm with the pistons having some clearance, or is it the other way around?
thanks guyz, still learning
Posted: Tue May 01, 2012 11:19 pm
Author: zed1015
If these bores are used/worn you will need to have them honed to provide a fresh surface for new rings.
This will most likely create too much clearance for any pistons you get.
Better to get some 70mm pistons (which is max bore for the 900 liners) and get the block bored for them.
The cost for the bore job won't be much more than just the hone.
The machinist who bores the block will allocate a piston for each liner and bore each liner with the correct clearance for it's particular piston.
You cannot get the block bored correctly without having the pistons to work off.