MS 660 Cylinder Compression

[StihlNick]

Picked up a weathered 660 last night for $500. Plastics are faded. Measured 158 psi cylinder compression and was wondering how this measures to Factory specs. Starts 2 pulls. Runs great. Ordered Factory Dual Port and new Badge for top cover.

 

[blsnelling]

That's very good compression.

 

[StihlNick]

Should I do anything to the baffles or the ports on the dual port muffler that will help with performance?

 

[blsnelling]

I would still open up the muffler body opening as large as the deflector will cover. Take it all the way back and to both sides. Do not bring it forward. You can also widen the slot int he DP cover. I would open the interior baffle as well.

 

[StihlNick]

OK thanks a ton! Next I would assume Pull the caps and retune? How many turns out is a good place to start?? Thank you for your time.

 

[blsnelling]

OK thanks a ton! Next I would assume Pull the caps and retune? How many turns out is a good place to start?? Thank you for your time.

Absolutely. I like to start at 1 1/4 each and fine tune from there.

 

[Iceboy]

Picked up a weathered 660 last night for $500. Plastics are faded. Measured 158 psi cylinder compression and was wondering how this measures to Factory specs. Starts 2 pulls. Runs great. Ordered Factory Dual Port and new Badge for top cover.
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158psi for a MS660 and for $500??? That sound like good deal.

 

[Ryan'smilling]

158psi for a MS660 and for $500??? That sound like good deal.

Looks like a heck of a deal from where I'm sitting too. Especially with a decent sized bar and chain and double dogs already on the saw. That stuff adds up.