Stihl MS 661 7 vs. 8 Tooth Sprocket

I run 36" and 20" bars with both a 7-tooth (standard), and 8-tooth sprocket, and compare.

[@anthonypryor2852]

If you can file chain well the advantage with mild porting and exhaust work is with the 8 pin. Used it for 40 years

[@brentw9809]

I put a 8 tooth sprocket on my 395 I love it

[@danielbargas3377]

I like the 8 tooth for 30 inch and under

[@CTSCAPER]

I just got an 8 tooth for my 066 to use with a 20" bar for milling. I'm looking forward to the results.

[@Human1337]

Oh yeah! That setup is amazing.

[@thejackel1844]

Simply put , an 8 tooth sprocket will increase chain speed, ( Limbing ) . A 7 tooth sprocket will increase bottom end torque ( Felling, Bucking ) ...

[@jgartmann]

why would you chose to limb with a 661

[@dustinshort6207]

@@jgartmann man needs to cut some big limbs lol

[@Dyno625]

Thanks for the comparison video. I have an 8 tooth for my 661 but have not tried it yet. Looks like it will by fine with my 28" bar

[@tonyg.2294]

time to spring for a mic brother, ur killin me!

[@milesff7]

I run an 8 tooth on my 461 with a 20" bar, and on my 661 with a 28" bar. You have to consider that by increasing the diameter of your sprocket, you're decreasing the torque output of your saw. In the end, run a shorter bar with the faster chain speed to see the benefit.

[@Human1337]

That's exactly why I didn't think that it would do so well with the 36" bar, and decided to include the 20", was surprised at how well it did perform. Today for the first time, ran the 8-tooth sprocket, with the 36" bar, and a square ground chain, not sure how well it would have done without the muffler mod I just did, but with it, it was a cutting beast, was a joy to run.

[@milesff7]

Human what was the diameter of the opening hole you drilled in the muffler modification? I'm going to wait till my warrantee has expired, but I want to do the same.

[@Human1337]

Not 100%, but I believe it was 1/2". Biggest bit in the set, though you don't have to use that size, can go bigger or smaller, all pretty subjective.

[@Vinson351]

Where did you get an 8tooth? I’m having a hard time finding one for my 661.

[@Fabzacres]

Only drawback (and probably slight) is that the increased diameter of 8 pin might put more wear on the bar rails

[@anthonypryor2852]

It puts less wear.

[@kiteslights7189]

heck that saw has a ton of torque

[@kurtfniessl5987]

Fuck ya try climbing with it. I get bitched constantly about how I sharpen my spurs on site. If you don't have razor sharp spurs you can't run a 661 with a 36" bar. I just tell my boss it's cheaper to sharpen spurs than get a lift in.

[@stihlnz]

Who would have thought .. thanks Human .. going to change out my 660's to 8 ..will look at my 460's and the 880 too. Well done, owe you a beer. Ever down in Wanaka New Zealand after this virus blows over look me up.

[@Human1337]

I'd stay with a 7 on the 660 unless it's modded or less that a 36" bar, not a super torquey saw in my opinion

[@stihlnz]

@@Human1337 thanks for that advice, I run the 660/460 all with 24" more for bucking the big old man pines that I seem to get on to. ..then bring the 880 out for the bigger stuff cheers

[@stihlnz]

Good man Human, thanks for your info ..will be sure that my next sprocket is 8

[@dngendron]

Perfect choice in music 🤟🏼

[@bjimbosld]

I wanna see an 8 tooth sprocket with my 661 and my 16” 024 bar and chain but might not be worth the results in conversion price.

[@GoodDayFarm]

What chain? On both bars. Thanks! It sounded like the saw wasn't working as hard with the 8 tooth either, it would be interest to see a RPM comparison with both sprockets.

[@Human1337]

Both chains used were the stihl full chisel. RPM is really dependent on pressure applied, I find that it cuts smoothest as a substantially high rpm though, haven't put a tach on it while cutting, something maybe I should do.

[@GoodDayFarm]

Full comp or skip tooth? It would be interesting to see the RPM comparison....

[@mart446]

Human but what pitch? 3\8 or .404? im thinking of. getting the 36" bar but dont know if i should get one pitch or the other. .404 stays sharper longer and thats what i want...

[@0j0nn]

3/8 is good enough in my opinion

[@lagoonrd4173]

Mart seen a video on that, and it did stay sharper when the 3/8 took a dump on the same tree and same cut

[@liamdawson4365]

Interesting comparison, have you considered what that increased chain speed will do for any chainsaw protective clothing you may use?

[@joshuamusser8893]

I wouldn't test that

[@cbr600rrturbo]

I wonder how the 462 with a 8 pin & 28 bar would do?

[@timidater4803]

wouldnt be enough difference for me to change

[@Mr42960]

That's really surprising for how hard that wood looked with full comp rs chain. Were you pushing the saw much or just kinda floating it in the cut?

[@Human1337]

Not adding much at all, just a little. Anymore than that and the RPM's drop and it slows cutting speed.

[@benfairhall5331]

Ok so I’m totally confused now I have a 462 and I thought the 7 pin would increase chain speed overall leading to faster cut? (Well what I believe) yet on this it seems the 8 pin which I believe is a stock cuts faster yet with a slower chain speed? Why is this very confused

[@82f100swb]

You have it backwards, the more pins on the sprocket the higher the chain speed

[@rnilazarev2553]

STIHL 👍👍👍 💪💪💪

[@stihltech206]

Make sure your chaps are rated for it. The ones rated at that chain speed are special order only at most shops

[@Human1337]

I know you're correct, and was curious about what my actual chain speed was. Unable to find anything published, I found a calculator here www.madsens1.com/bnc_chn_speed.htm it's showing a chainspeed of 5,900 ftm with a 7-tooth, and 6,750 fpm with an 8 tooth. Wondering if this is correct, if so, not even close to the 2,750 fpm rating of my new chaps.....hmmm......

[@stihltech206]

Yeah, I did an in house chain speed project and came up with over 3500 in the cut with the 8 tooth... that's at about 8000-9000 rpm. With no load your numbers are correct

[@stihltech206]

Also, you CAN wear 2 pairs of chaps if you want. It DOES give you more protection... But you gotta cinch em up tight

[@ballerfaller7073]

I wear inserts in my clothes and I am almost sure even without a 8 tooth sprocket most pro saws will cut right through. They are there as a added layer not as a catch all. Best to just know what the saw is capable of and be carful.

[@kiteslights7189]

I wounder how my older 660 would do with a 8 tooth on a 36 inch might have to try it I ran a 8 tooth on a 30 did fine

[@moaski]

What’s the part number for the 8-tooth sprocket?

[@donniepatton1523]

I have a question, I have a Stihl MS 660 and a Stihl .404 pitch, .063 gauge bow bar. Can I adapt the saw to run this bow with a # 46RS chain? I am prepared to make an odd length chain.

[@twostrokeandsawdust]

Nice comparison! I run an 8 tooth sprocket on my ported ms880, with full chisel .404 on a 42 inch bar it is approx 11 seconds per cut faster thru a 38 inch log than a 7 tooth. would an 8 tooth be better for running skip chain?

[@Human1337]

I would certainly think so, as a skip tooth is made to be less strain on the engine on large size bars. 8 tooth sprocket would likely pair perfectly with a big skip tooth.

[@twostrokeandsawdust]

Jason Hayes that sounds about right, the rpm would be similar, i run 8 tooth on both my saws now, the 880 set up with .404 and my 460 set up with 3/8, only reason I'd use a 7 tooth sprocket again would be for milling or breaking in/ stretching a new chain.

[@twostrokeandsawdust]

Jason Hayes you should have no trouble running an 8 tooth on a 660, what length bar do you run? my 880 runs with a 42 inch all day, but any bigger and i think the 7 tooth would have to go back on to get the torque back up.

[@oliverm5sc]

Your letting the saw rev too much with the 7 tooth, not in the peak power RPM. Push on it a little or take the rakers down a tad

[@sellsn01]

You mentioned in the 660 video, you thought you could go up from the 36" bar. Do you feel the same for the 661 cm?

[@Human1337]

Absolutely. I would put on a skip tooth chain though, pulls my full comp great at 36", not sure about full comp any larger than that.

[@nickinnewy7567]

stupid question, but can i get away with the same chain length going up to an 8 tooth sprocket, or do i have to add a link?

[@Human1337]

It's a little bit of a tight fit, but I use the same chains.

[@nickinnewy7567]

Hey Mate, thanks heaps, and can ya tell me again what you were saying about the oiling, push what button in? I've neva had the 661 oiling the bar right.

[@gregmenniges5963]

Miss you dude

[@DanielDauphin]

Why would you ever put a 20" bar on a big saw like this?

[@Human1337]

No reason, just playing around.

[@jwinn4886]

I often run a 24" bar on my 066 (8 tooth sprocket). Bucking a lot of firewood it's just a time saver.

[@FishFind3000]

Nice looking saw. Is it m tronic?

[@Human1337]

yes sir, same saw I used in the 661 c-m review. pride and joy =) Now if I could only get her to go on a diet....

[@Fabzacres]

U

[@mathewkromeo2934]

I've never cut wood or used a chainsaw before. I just bought a 661. 😳 I'm going to get some lessons and lots of safety gear..There must be some pros to buying a big ass saw for a first saw, right?

[@MrPaddy1000111]

Big saws are safer. Less kick back and less dangerous. Small saws are light, have a lot of kickback, you have to bend over and be more unstable with bucking etc etc. You are far safer with a big saw. Good choice!

[@Vinson351]

@@MrPaddy1000111 except a big saw has two to five times the horsepower. I have a ms250 and a ms661. I wouldn’t recommend a 661 as a first saw. Bigger saws kickback a lot harder than a small one and usually kick back just as fast. I can manhandle the 250 in most kickback situations the 661 I cannot. Don’t give people stupid advice.

[@MrPaddy1000111]

@@Vinson351 Sorry but you're wrong. There's a reason why top handle compact arborist saws can't be sold to the general public (at least in the UK). Small saws kick back fast and people feel too safe around them so they do stupid things. I can put my ms881 in a cut and leave it in there with one hand on it because I know darn well it ain't going to kick back because of the weight. Kickback isn't about horsepower it's about chain speed and weight. A high chain speed and a low weight will kick back like hell which is why they put anti-kickback chains on small saws. A heavy saw with a lower chainspeed will kick back less.

[@Vinson351]

@@MrPaddy1000111 I’ve never hear of such crap. I’m sure people have been hurt by them but I have literally never seen anyone injured by a top handle saw. I’ve also been on the fire department for 14 years. Have never seen anyone injured with one of those during that time either. If you think chain speed is different between the two you obviously don’t know about diameters and rpm. The bigger saws have a bigger sprocket and turn the same engine rpms in many cases. Do you math. I have seen hundreds of injuries from people with bigger saws. The bigger the saw the bigger the injury was. Also about not being able to buy them in the UK. It’s a nanny state over there where you have to have permission to wipe your ass. So it wouldn’t surprise me that they tell you that you couldn’t buy a saw. Your 880 touches a tree or anything that will make a kickback situation it will jump out of that cut. Don’t think it won’t because it hasn’t. It can happen.

[@MrPaddy1000111]

@@Vinson351 sorry mate but the H&S reports are completely different to what you say. Why would the fire service be called to a chainsaw injury? 😂 why would you not be able to buy a top handle without cs31 and why would you have to do training to crosscut with larger saws before being able to train with top handles. I take it you aren't a fully certificated tree surgeon (I am) and I do it for a living. I've seen people cut themselves with smaller saws and even silky saws more than big saws. In fact, I don't know anyone who's had an injury from the big stuff. Smaller saws like an ms200t has a higher chain speed than a ms881. A 200t tops out at 14,000 an 881 tops out at 11,000. The sprocket on big saws is larger but not enough to make a 3000rpm difference. The main thing that might give a larger saw more kickback is it not being fitted with a consumer grade safety chain

[@SMiller5488]

Would a 8 tooth work good on a 362 running a 20in. bar?

[@Human1337]

Mine didn't like it too much. Many factors come into play though, mine wasn't fully broken in, and I'm sure the chain was a bit aggresive. I'll have to try it again in the future.

[@itzOLE3]

Ever change the sprocket on a 200t??

[@Human1337]

Yeah, I'm running a 7 tooth on mine now.

[@Anonymous-uu5nc]

Would you recommend an 8 tooth on the 461?

[@Human1337]

I'd guess that it depends on the bar size. With the way my 661 ran the 36, I would think the 461 would have no problem pulling a 30 with an 8-tooth.

[@D2500R]

Tim B I have a 461 and recently went to an 8 pin. Have not regretted my decision as it runs a decent amount faster and has the hp to back it up. 28" bar

[@CNKCLAN2]

Anyone have the part number for the 3/8 8T (8-tooth) rim sprocket for my 661C? Looking to try one out vs the standard 7-tooth it comes with. Want to make sure it works and don't trust the Chinese knock offs.

[@pieinthesky4106]

From my experience, the Chinese sprockets are well made and just as good in performance durability.

[@lifeisgood070]

recommended for an MS 362?

[@Human1337]

Can't say, when I tried it my 362 wasn't really broken in yet, but my gut tells me that I'm going to stick with the stock rim.

[@edwardungerman4057]

get some better chains. my 026 throws bigger chips. 33 rsk

[@tomyousch7070]

Prue bs