Swapping out a busted worm drive for a 6T Picco with a 7T Picco for my MS201T?

[pining_fir_yew]

I don't have a replacement worm drive on hand for the 3/8 Picco 6T clutch drum (1129/00A) but I do have a Picco 7T 3/8 clutch drum and worm drive in the parts bin. Can I safely swap it out until the replacement parts arrive? Currently running the 16" 9T Rollomatic E Bar with the recommended 63PMC3 3/8 Picco chain. I'm assuming a 7 Spur sprocket will have less torque and more speed than a 6 Spur, that's not really a huge deal for now. We are working on red oaks all next week and I'd rather not have to use the spare 540xp in the interim.

All the parts seem to fit together well, and I'm having trouble finding anything that specifies compatibility one way or the other.

edit: sorry if this is a dum dum question...

 

[Bob Hedgecutter]

I believe you can- not done so on the 201, but the 200T ran 6 tooth here and the MS200 (rear handle) ran a 7 and the parts interchange.
@lone wolf should be able to confirm for you though- he knows a thing or two more about these than I do.

 

[pining_fir_yew]

I believe you can- not done so on the 201, but the 200T ran 6 tooth here and the MS200 (rear handle) ran a 7 and the parts interchange.
@lone wolf should be able to confirm for you though- he knows a thing or two more about these than I do.

Thank you! I was too shy to tag the resident expert myself heh

 

[lone wolf]

I don't have a replacement worm drive on hand for the 3/8 Picco 6T clutch drum (1129/00A) but I do have a Picco 7T 3/8 clutch drum and worm drive in the parts bin. Can I safely swap it out until the replacement parts arrive? Currently running the 16" 9T Rollomatic E Bar with the recommended 63PMC3 3/8 Picco chain. I'm assuming a 7 Spur sprocket will have less torque and more speed than a 6 Spur, that's not really a huge deal for now. We are working on red oaks all next week and I'd rather not have to use the spare 540xp in the interim.

All the parts seem to fit together well, and I'm having trouble finding anything that specifies compatibility one way or the other.

edit: sorry if this is a dum dum question...

IDK on the 201 but prob, just see if it fits and works. Look before you put it on by checking the drive lugs make sure they match up and fit in the drum sprocket, know what I Mean?

 

[pining_fir_yew]

IDK on the 201 but prob just see if it fits and works.

Thanks! I didn’t have anything on hand to do a test cut but it felt normal under throttle - so far so good

 

[lone wolf]

Thanks! I didn’t have anything on hand to do a test cut but it felt normal under throttle - so far so good

Is it oiling?

 

[pining_fir_yew]

Is it oiling?

Yup! The worm drives seem identical apart from the cut outs for a 7 rather than 6 spur. The only thing I’m slightly worried about is a noticeable loss in torque, which in theory the extra tooth would cause? Idk. Though it’s not like im flush cutting stumps with it so im guessing its probably not going to be an efficiency issue

 

[lone wolf]

Yup! The worm drives seem identical apart from the cut outs for a 7 rather than 6 spur. The only thing I’m slightly worried about is a noticeable loss in torque, which in theory the extra tooth would cause? Idk. Though it’s not like im flush cutting stumps with it so im guessing its probably not going to be an efficiency issue

What size bar did the saw it came from have and what bar now?

 

[pining_fir_yew]

Hmm good question, we run our 200T with a 14” bar but the 201 has a 16” one. It was purchased before my time but I’d say the saw originally was fitted with the 16” - just bc if anything we go down sizes from the saw’s original factory fittings.

Edit: Oh sorry I miss read that. The 7 spur was some thing I just picked out of the bin of parts that were probably ordered on accident. I kept the same bar that I had originally - the rollomatic picco 3/8 .050 with a nine tooth sprocket

 

[lone wolf]

Hmm good question, we run our 200T with a 14” bar but the 201 has a 16” one. It was purchased before my time but I’d say the saw originally was fitted with the 16” - just bc if anything we go down sizes from the saw’s original factory fittings.

Well I would say the larger tooth sprocket would be better on the 14 not the 16 and vice versa. Now what is the combo you now have?

 

[pining_fir_yew]

Well I would say the larger tooth sprocket would be better on the 14 not the 16 and vice versa. Now what is the combo you now have?

That makes sense now that I think about it. The 6 spur kind of felt clunky on the chain even when it was new. Hmm interesting.

So now it’s 7 spur sprocket on a 16. Smaller tooth as in you add the 7th they get smaller right?

 

[lone wolf]

That makes sense now that I think about it. The 6 spur kind of felt clunky on the chain even when it was new. Hmm interesting.

So now it’s 7 spur sprocket on a 16. Smaller tooth as in you add the 7th they get smaller right?

7 tooth on the 16 bar will drop the torque some, put on the 14 in bar with that one. The more teeth the more chain speed and less torque.

 

[pining_fir_yew]

7 tooth on the 16 bar will drop the torque some, put on the 14 in bar with that one. The more teeth the more chain speed and less torque.

gotcha, will do. I doubt I’ll miss the extra 2 inches as much as I’d miss the torque.

 

[Captain Bruce]

I don't have a replacement worm drive on hand for the 3/8 Picco 6T clutch drum (1129/00A) but I do have a Picco 7T 3/8 clutch drum and worm drive in the parts bin. Can I safely swap it out until the replacement parts arrive? Currently running the 16" 9T Rollomatic E Bar with the recommended 63PMC3 3/8 Picco chain. I'm assuming a 7 Spur sprocket will have less torque and more speed than a 6 Spur, that's not really a huge deal for now. We are working on red oaks all next week and I'd rather not have to use the spare 540xp in the interim.

All the parts seem to fit together well, and I'm having trouble finding anything that specifies compatibility one way or the other.

edit: sorry if this is a dum dum question...

With your experience, WE will all assume you have the IPL for your top-handle in hand. Your asking if 2 parts are compatible? The parts list diagram answers that, without all the wasted keyboard time......any climber is worthy of $100 ++ / hr. Your question involves a $10 part? Go get what you feel is needed.....?

as to the difference in performance? Who cares; you are tool-blocked. Get the job done, and than order the parts x 2, and "spare "yourself, and the forum, any further such issues..?? Just saying.......

 

[pining_fir_yew]

Hi Bruce,

Yes I’ve referred to the IPL and it does list the 6 Spur Sprocket as the correct part but also includes the caveat that there may be other options made by stihl not listed in the manual.
So yes -

The parts list diagram answers that

- but only in part.

Go get what you feel is needed.....?

I don’t have a stihl supplier that has such a specific item on inventory so I need to wait for the replacement worm drive to arrive.

"spare "yourself, and the forum, any further such issues..??

The reason why I ultimately decided to post the question was because I spent about an hour searching past forum posts without finding a conclusive answer. I also looked over stihl’s part catalogues and was fairly sure that it was an appropriate substitute for the interim. But I wanted to get a second opinion so here I am.

Yes I’m tool locked but I’m trying to do my due diligence before charging full steam ahead using a saw that I didn’t purchase with my own money. Especially due to the fact that I’m not about to use the janky T540xp nor would I run a saw that isn’t oiling.

I appreciate @lone wolf and @Bobhedgecutter for helping me out when they could have let this post languish as just another saw question that takes up space on the forum without a conclusive answer in the replies. it can at least offer that value to queries in the future.

 

[pining_fir_yew]

Just for everyone’s reference, the 7 spur lost some torque with the 16” bar but it was only slightly noticeable. It’ll suffice!

 

[lone wolf]

Just for everyone’s reference, the 7 spur lost some torque with the 16” bar but it was only slightly noticeable. It’ll suffice!

I suppose it did ! But you are running .