New Forester rim sprocket, won't align with MS290 chain

[RedOctobyr]

I just got an MS290, and ordered a Forester-brand rim sprocket and clutch housing for it. 3/8", 7T, to match the 3/8" chains and bar I already have.

It's part # ST316SCA757, from this eBay listing:
http://www.ebay.com/itm/Forester-Re...t=LH_DefaultDomain_0&var=&hash=item416eeffe28

The box that arrived shows the proper model #'s on the label.

I just installed it, which went pretty easily. But the chain doesn't line up with the sprocket. When the bar is against the mounting surface, the sprocket is too far away from the body of the saw (to the right, if you were holding the saw).

So the chain can't line up with the sprocket properly, and you can't rotate the chain by hand. The E-clip can be installed on the end of the crankshaft, with the sprocket installed. I have pushed the clutch housing towards the engine as far as it will go.

Am I missing something? Are the Forester rim sprockets supposed to be OK? My usage is only if a tree falls down on my property, so longevity isn't really an issue. Thanks.

 

[a. palmer jr.]

I see what you mean, the rim is too far to the right. I think the big part of the sprocket, the part that goes next to the brake should just about be flush with the body of the saw, only the splined part and rim should stick out. Either the clutch needs to go in further or you have some mis-matched parts. Most of the 290s I've seen use spur sprockets.

 

[huskihl]

Is the notch on the inside of the clutch lined up with the oil pump worm spring?

 

[RedOctobyr]

Thank you for pointing that out, I'm sure it was not properly aligned when I tried before But I just tried multiple times to align with that spring, and it does not seem to push on any further.

With the Stihl spur sprocket, it feels & sounds different when it seats, if you have that aligned with the spring properly, vs being wrong. But with this clutch housing, I can't tell a difference, if I line it up nicely, or deliberately do it wrong.

And I can install the E-clip on the end of the shaft, so I think the clutch piece is seated fully. If it had the ability to slide on another 0.1", for instance, I'd expect I couldn't get the E-clip on?

 

[huskihl]

If you put the drum on wrong intentionally, make note of how far the crank sticks out. Then attempt to install it correctly and you'll notice another .050"(guessing) or so when it's lined up.
Also, make sure the brake band is in between the notches on the case.
And make sure the washer is on the correct way. On mine, there's a recessed area for the clip

 

[AKDoug]

This is the second one of these this week on this board. The other one was an Oregon rim sprocket. Maybe you guys should buy them from Stihl ?

 

[a. palmer jr.]

I bought a new aftermarket sprocket for my 029. I'll let you know in a few days if it fits. Putting the engine together right now..

 

[ChoppyChoppy]

I have a 290 on the bench with rim sprocket and it works fine. Do you need.measurements?

I think it's Iregon, but.might be Stihl, been a few days and few saws since I messed with it (waiting on parts)

 

[RedOctobyr]

If you put the drum on wrong intentionally, make note of how far the crank sticks out. Then attempt to install it correctly and you'll notice another .050"(guessing) or so when it's lined up.
Also, make sure the brake band is in between the notches on the case.
And make sure the washer is on the correct way. On mine, there's a recessed area for the clip

Good suggestions, thank you. When I tried last night, I did not notice a difference in how far the crank stuck out with the Forester unit, whether I lined up the notch with the spring, or deliberately mis-aligned it. I had not looked at anything regarding the brake band; nothing jumped out at me as seeming weird, or binding, but I'll take a closer look. The washer is on correctly, the E-clip goes into the recess.

AKDoug, thank you for the heads up, I searched and found that other thread. That's good to know, because the Oregon version was the "high-end" option I was considering for a rim sprocket I should find out what the Stihl version costs.

I must confess, the inability to buy Stihl parts online makes me more likely to go aftermarket. I can get pricing for other online options on a Sunday, and I can order them easily. I don't even *know* what the Stihl one costs, and can't find out if the dealer isn't open, plus they may not have it in-stock, then I need to get there when the dealer is actually open, etc etc. I'm sure Stihl has their reasons for this business model, but it feels a bit like not keeping up with the times, if I'm apparently not allowed to even buy their parts online.

I may try to get some measurements off the Stihl clutch housing, vs the Forester, to see what that shows. But the end result, so far, *appears* to be that the Forester is simply shaped wrong.

I'll see what the eBay seller says about the situation, as well. If they simply shipped me the wrong part, then it's subtle, because it appears to fit, until you put the chain on.

 

[Franny K]

If it is just a little bit and the replacement is a bit thicker than the original just thin it down a little with a grinder. I found myself in that situation once.

What you linked in post 1 is a drum and sprocket assembly, not what I mentioned about above. You need to measure the thickness of the drum from where it hits the crank or clutch and the inward most point the rim sprocket can go and compare that with the original.

 

[a. palmer jr.]

The part number of what you bought is listed in his ad. You might see if the part number on the actual part matches the number in his ad for your 290. You could also sit the two sprockets next to each other on a flat surface and see if the height is the same on both sprockets.

 

[nnero]

I had the same issue when putting my 7900 back together. It ended being that the brake band was binding just a little bit causing the drum to not be seated all the way. Double check that and compare the new drum to old drum and look for differences. Does the 290 have the oil pump that runs at idle or not? Make sure the spring from the pump is in the groove on the drum, if you have that style pump

 

[Sagetown]

I learned the hard way. Just buy Stihl Rims, and you won't go wrong.

 

[old-cat]

I had the same problem with an aftermarket rim sprocket for an ms290 and the seller refused to refund the price so I gave up.

 

[nnero]

I forgot about that. You can only use a Stihl rim on a Stihl drum too, at least Im pretty sure

 

[RedOctobyr]

Sagetown, thanks for showing those measurements. The Forester is about 0.750-0.755" on the inside, so their sprockets are not compatible with anything else. That's too bad.

(edit- I mean that their sprockets do not seem compatible/interchangeable with, for instance, Stihl or Oregon sprockets, since the hub diameters are different)

Sent using Tapatalk.

 

[old-cat]

Sagetown, thanks for showing those measurements. The Forester is about 0.750-0.755" on the inside, so their sprockets are not compatible with anything else. That's too bad.

Sent using Tapatalk.

Those sprockets fit the 346 and 353 Husky saws and the Husky makes that ms290 look like a drunk pig!

 

[CR888]

The rim drive spocket should 'float' on the drum splines and have room to move. The problem with 'cheapest on bay' rim sprockets is they sometimes have imperfections on the inner spline grooves that jam it on the drum spline rather than sliding on and being able to float. Non OEM sprockets are hit and miss and sometimes need a few touch ups with a file to get a better fit. Some will never fit and need to be tossed but with a bit of work and determination you can fix the china Q/C issues.

 

[Stihlofadeal64]

This is the second one of these this week on this board. The other one was an Oregon rim sprocket. Maybe you guys should buy them from Stihl ?

There is a problem with these sprockets. I purchased a few of them, and none of them worked. I had the same alignment problem. My advice is the same -- buy a Stihl sprocket, you can get the rim set up for your saw, and be done with it. Sad news, but true news.

 

[a. palmer jr.]

If you buy from a local shop rather than online you can take your old sprocket with you and see if they match. Kinda hard to do on the bay..