Stihl MS661 - Air Filter Cover Mods

[@joescissorhands141]

Thanks a TON for doing the #'s on this!! Was pretty sure the best bet was "modded OEM airbox with fresh HD2's", ie most economical & practical, it's nice seeing confirmation! I have a ~10sec clip that shows mine, don't wanna link here on your vid but you can get that extra flow to the air-filter *w/o* cracking the airbox (like yours where the bottom edge is now gone, that entire rectangle needs to mate-up for it to press the filter into the carb-wall properly), you can instead just open holes in the main airbox and line with filter-paper or whatever and not only get that huge increase in CFM potential, but it's pre-filtered so filter cleaning interval is *way* up!!

[@StihlChainsaws]

Regardless, it's a cool video & some great content! STAY SAFE

[@Redbull661]

thank you sir

[@brad7989]

Maxflow FTW!

[@98durangopack]

So for my 661 carb, if I keep factory airfilter and do the cover mod do I need to adjust the carb?

[@ocsplc]

If you’re introducing more air flow probably

[@heathhigdon2815]

Nice video, very informative

[@StihlChainsaws]

I understand your thoughts on air flow, but dont you get more chip build up with those holes. You say it gives it a spot for the chips to escape, but it's taking air in & not releasing air there. Am I wrong, cause my experience with it is I get a lot more build up with chips without air cover or with modded air cover?

[@Redbull661]

in the summer if it's not raining I run no cover because I've noticed almost zero chip accumulation in the filter. As for the physics going on. I guess honestly I couldn't articulate what/why it's happening that way.

[@pentecost66]

Some run them with no covers,just wondering your thoughts. Also what’s up with the 404 any advantage’s.

[@Redbull661]

I have run with no cover many times. It's fine unless it's raining :). 404 just lasts longer. Stays sharper longer. Can take more beating. More meat so longer chain life. 661 has the power to pull it.

[@nickb6162]

So was there any difference in times ? You think a 461 cover would benefit from modifying?

[@Redbull661]

max flow is faster. no doubt

[@rickfinzel]

doesnt the 661 have the new electronic carb? if so wouldnt u have to reset it to truly get the best out of it after increasing air?

[@Redbull661]

it adjusts to most changes to the saw just like it adjusts to environmental changes on it's own. Now if I took a stock saw and then did a muffler mod, air filter mod, timing advance, and ported the cylinder all at once I might do a reset. But generally unless I am having problems with the saw I don't do a reset. I've experimented with doing it quite a bit over the last 3 years and that is where I am currently at on the subject.

[@rickfinzel]

@@Redbull661 ok was just wondering all of my saws are the older style

[@Redbull661]

yes sir. yeah been trying to beat the mtronic with standard carb and can't do it. mtronic is always correct tune.

[@calebwillhelm2635]

Redbull661 How are they able to accomplish that and still be on EPAs good side

[@air2bmc]

What tank/handle guard is that?

[@Treeesmith]

Ever run the max flow with the modded oem cover?

[@Redbull661]

doesn't really fit well.

[@ocsplc]

Get rid of that lightweight bar and gravity will eat that Ash faster with a quality regular steel bar. MHO

[@benredmond8271]

Yea why 404? 3/8 cuts faster in my experience. I only run 404 on my 088

[@Redbull661]

lasts forever

[@bladigonzalez4182]

@@Redbull661 buenas dias compre

[@bladigonzalez4182]

Me puedes ayudar talvez