# Stihl BR550 BackPack Blower Crankshaft



## Stihlskin (Jul 24, 2016)

Hello All. Stihl BR550. I have removed the spur gear that drives the plastic cam-gear as part of crank service, replace bearings, seals etc. I notice the spur gear doesn't have a keyway or alignment marks. Workshop manual provides no spec for this.

* Can someone pls provide a advice or a guide for the crank spur gear tooth alignment as it will prob adverse to the valve timing if I position it wrong. Thanks


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## backhoelover (Jul 24, 2016)

just slide the spur gear on does not have a certain way it goes. timing is done with the. flywheel, coil, marks on cam and mark on case where cam slides in. here is info to help


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## backhoelover (Jul 24, 2016)

on the svc manual info starts on page 16


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## Stihlskin (Jul 25, 2016)

backhoelover said:


> just slide the spur gear on does not have a certain way it goes. timing is done with the. flywheel, coil, marks on cam and mark on case where cam slides in. here is info to help



Thanks for that. Ok, just slip it on and set up the cam-gear as per workshop spec. Very much appreciated. Thank you.


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## PhilKawasakiuser (Aug 18, 2016)

I had the flywheel key get torn up and my flywheel was out of alignment when the basic valve adjustments were done. I was wondering what I need to do to get that blower back running again? Can I just replace the flywheel and expect the timing to be like it should be? I only am thinking this because I had to reposition the flywheel on a chainsaw and it was pretty straight forward. Thanks for any help


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## ANewSawyer (Aug 20, 2016)

I don't know of any reason it would matter. You should be able to replace the flywheel or retime and go.


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## PhilKawasakiuser (Sep 15, 2016)

You don't think it would have the valves set wrong cause of the flywheel being off during the valve resetting?


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## ANewSawyer (Sep 15, 2016)

As far as I know, valve timing is set by the cam which is geared to the crankshaft.

But, you must align the mark on the flywheel with the first coil bolt on the trimmers. You can't do that without flywheel easily. Just follow the info Backhoelover posted.


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## backhoelover (Sep 15, 2016)

sound like something got stuck in the timing gear and everthing came to a complete stop and the flywheel keep in motion and sheared the key. i would check gear with came plate off. also need to check the holes for the rode that hold the cam and cam followers in place i have seen where on the cylinder the rods go be reamed out and cause problems.


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## backhoelover (Sep 15, 2016)

you also have to make sure you are not in valve overlap when you setting the valves. this is where both valve have slight pressure from the rocker. if you are in valve overlap you need to turn the flywheel another rev and then you are ready to set the valves.


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## PhilKawasakiuser (Sep 16, 2016)

I have a BR500 thats not functioning. I believe I can use the flywheel off it right? Just got a FS130 lastnight for parts. Seems like it might be a runner but not sure yet. People give up on there old tools and replace often for no good reason but they want new. I will never throw any gas tools away and my best tools were previously given up on and discarded. Id never be able to afford my collection if I paid new for it. So I have somethings that feel like a work in progress for life and others that never took but a couple minutes and are running great again. I don't get what is wrong with people throwing away stuff that is atleast good for parts or they could part out and make some money. A neighbor I just found out has almost as many chainsaws as me but mine almost all run great and non of his even start. He has 14 currently. Five are homelite ryobi junk. 5 are old and damaged but the rest look like he used them once. He says he buys one every fall since his old one never will start but once. I looked at one of his and it started for me. What is the deal. These pro quality tools aren't cheap.


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## davhul (Sep 19, 2016)

Stihlskin said:


> Hello All. Stihl BR550. I have removed the spur gear that drives the plastic cam-gear as part of crank service, replace bearings, seals etc. I notice the spur gear doesn't have a keyway or alignment marks. Workshop manual provides no spec for this.
> 
> * Can someone pls provide a advice or a guide for the crank spur gear tooth alignment as it will prob adverse to the valve timing if I position it wrong. Thanks


Do you have any up and down movement in the crank. If so the flywheel will hit the coil. Then you know bearings are bad.


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## PhilKawasakiuser (Sep 29, 2016)

I don't have any that I can notice. I did a vac test on it about a month or two before this whole mess got started and I believe it passed with flying colors. Thanks tho for the warning but the reason that this got sheered was there was a screw that got picked up probably from the back of a pickup I had hauled it in just before. Thanks


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