Ohlsson & Rice: Gearbox Sprocket Removal

[CNew 403]

I am trying to disassemble a gearbox off an O&R chainsaw and it looks as though the sprocket should separate from the main gear shaft. I removed the little 5/16” head screw but the sprocket is not budging. I attempted some slight prying with a screw driver as well as some light tapping with a flat head punch. Nothing seems to work. Before I go any further and risk damaging something does anyone have any suggestions on what I might try?

 

Thanks,

Clint

[factory 483]

It's supposed to come off the same way as the flywheel does, i.e. loosen the screw & strike the it sharply to free the sprocket from the taper.

But I have also found they don't always want to come off easily too, I would try a parallel punch that fits in the screw hole, as hitting the screw a lot may damage the threads (I can't remember if it had a left hand thread too).

If there wasn't a seal & possibly a plastic bearing race used for the shaft, I would have tried heating the sprocket to try & free it.

 

For reference here is the sprocket removal procedure given in the chainsaw maintenance manual;

 

David

[CNew 403]

David,

   Awesome, thank you very much for the recommendations and for sending the removal info from the manual.  I’ll give these approaches a try. 

 

Much appreciate!

 

Clint

[CNew 403]

David,

   Success, I was finally able to get the sprocket free from the taper. It took some negotiation before it finally let loose, definitely being stubborn... It even started separating the center shaft splines from the main gear hub but I was able to tap that all back together ok.  That was probably more work than needed just to clean up the case of old grease but it’ll be peace of mind knowing it was all cleaned and the bearings were checked and greased and the gear itself is all free of old gunk.

 

I appreciate all all the help!

 

Clint