New MS660 MM questions

[1dragon]

Okay guys some ramblings, questions and what not. MM'd the 660 today and retuned the carb. I drilled a hole directly in front of the exhaust port 9/16" in diameter. Next I opened up the side port as far as i dared due to the way the deflector is. Seemed to maybe gained some, but I did refill it with 50to1 Stihl Ultra and premium. the old owner had 40to1 Stihl non synthetic and premium, so maybe I felt that instead. I did leave the screen in, I don't think I could feel the difference like I did when I MM'd the 029. does this sound right? Should i do more internally to the muffler? It didn't really seem any louder, not that I'm really after that side of it.

I just hope after I get this skip chain off and go full comp that it will pull an 8 pin 28" bar. I am just really not as impressed as i am with my 029/039 8 pin 18". Currently the 660 has a 7 pin. Am i really missing something here? i'm not talking that I had the 28" bar buried, used the same stump to test and tune the 029/039 on. I will say it was harder to bog the 660 after the MM and different fuel mix.

Another note is the old owner talked about how fast it would gulp fuel. I was surprised just tuning and cutting some i burned half a tank. :msp_scared: LOL

Thanks for the patience guy's as this is my first big saw and i'm just rambling on.:taped:

 

[struggle]

When I did mine I completely ground out the internal baffle. It needs to be compltely removed and yes it will be louder when done.

 

[1dragon]

Okay thanks' I'll do that then.

 

[albert]

IMO stock late 066's and 660's do not beneifit from going overkill on large muffler openings. Drop the cylinder and do some machine and port work, then larger is in order.

 

[1dragon]

IMO stock late 066's and 660's do not beneifit from going overkill on large muffler openings. Drop the cylinder and do some machine and port work, then larger is in order.

Well I have to say i've considered pulling the jug and seeing if i could ditch the gasket. I have ported and polished several automotive heads but really don't know the in's and out's of 2 strokes. I assume you check squish with something on the piston that will squish down so you can mic the distance. I also assume you want to widen both intake and exhaust ports, as well as port the top of the exhaust port and the bottom of the intake. Am I close here? Saw runs great as far as starting, idling and all. Don't want to screw my new to me saw up.

 

[struggle]

I would be extremely cautious on porting it. The 660 isn't as easy as others from what I have read here.

It is a lot easier to screw it up than make it run stronger.

 

[1dragon]

Well I don't believe it would be the saw I would want to do my first port job on. However I wouldn't have a problem trying to ditch the base gasket. I think I would be relatively safe doing that. Not sure how much of a benefit just doing that would be though. Wish I had the coin to send it to one of the pro's on here and get her ported.