Stihl Early 066 vs M-tronic 661 Standard HD-2 vs Maxy (Max-Flow)

The 3rd in a series of videos of these two going head to head in various forms. The 066 has the Insane-O SS zippkit and the 661 was taken a little further to the Psy-Ko level.
It all started with both in "stockly", aka sickly, tune going head to head with the 066 coming out on top.
I zipped the 066 and it stomped the stockly 661 pretty handily. I then zipped the 661 and left it in m-tronic trim and it came around nicely but still was getting beat. I then swapped out the stock HD-2 air filtration system for a Max-flow assembly and the 661 pulled slightly ahead of the 066. This is the video log we are watching here.
Next on the list was an "operating system upgrade" where I took out the m-tronic components and put in the first & second version
unlimited coil and adjustable carburetor. That is video logged in the following two sessions.
It is important to note that the 066 is by no ways or means a slouch. My guess is that it will handle a 50" bar saw-weetly. I did take the 661 a little bit further tune wise than the 066 in the end.
I scrutinized the original clip thoroughly. Time runs as follows:
066 @ 13,500 K 14.17 & 13.42
661 @ 13,500 K 14.52 & 13.69 With the stock HD-2 assembly
661 @ 13,500 K 13.95 & 13.35 With the Max-Flow (Maxy) system
So we watched the M-tronic version with the stock air filtration system running just a fuzz behind the tractor power 066. Once the low cfm assembly was replaced with the high volume Maxy system we watched the 661 edge slight ahead of the 066.
I'm well pleased at how the builds turned out. I think the 066 will come around a little bit more with time as the new bearings and seals get more "comfortable" with the process. With any luck, the owner will give us an opinion/update at some point.
I am currently available for custom saw modifications. If you are interested, please shoot me an email.
[email protected]
Thanks for watching.