Stihl 661 vs Big Bore 064

Here we are watching the same 661 as seen in the previous 661/066 build sequence videos running against my newly upgraded 064.
I used a standard oem 660 cylinder assembly for this project.
Upon review of the dialog, I noticed a qualification was needed regarding the commentary about the differences in the combustion chamber work. The 661 chamber was reshaped along with the flow tricks added in. I did do the flow tricks to the 660 cylinder for the 064. I did not reshape the combustion chamber however.
As mentioned, there is a 1.2 pound difference in weight between these two when fully fueled.
Timed runs as follows:
661 @ 13,080 rpms 12.78 & 11.00
BB 064 @ 13,080 rpms 13.70 (cut out) 13.76 & 12.17
The 661 have some more work done and runs a little faster. The 064 runs a little slower but weighs quite a bit less.
I well pleased with the outcome of the 064 in BB trim.
I am currently available for custom saw modifications. please shoot me an email if you are interested.
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Thanks for watching.