Makita/Dolmar sprocket bearing lubrication

[Flint Mitch]

I have a fairly new to me Makita 6421(used rental saw). I noticed that the sprocket bearing gets dry fast. I use Lucas X-Tra heavy duty grease(it says it is for high speed bearings) but after about 2 hours of use the grease is gone. Am I doing something wrong? I don't like dry bearings!

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[Full Chisel]

I've wondered this myself...

 

[buzz sawyer]

Once the clutch engages the bearing does not turn so basically it only turns at idle. Never had a problem with bearing failure from lack of grease. I use a moly engine assembly grease. I believe it gets some lube from the bar oil as well - migrating into the bearing area.

 

[jackjcc]

I use white lithium grease. Ive never really been concerned with it. Every time I've taken the bearing out of a working saw its had bar oil on it. I figure that's probably doing the job.


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[Flint Mitch]

I use white lithium grease. Ive never really been concerned with it. Every time I've taken the bearing out of a working saw its had bar oil on it. I figure that's probably doing the job.


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Seems to be no bar oil getting to it. Could there be an issue with the saw?

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[jackjcc]

No, I wouldn't say that. It's just that bar oil usually gets everywhere. Turn up the oiler maybe? I always max them out, no such thing as too much oil.


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[Flint Mitch]

No, I wouldn't say that. It's just that bar oil usually gets everywhere. Turn up the oiler maybe? I always max them out, no such thing as too much oil.


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I'm maxed out, it oils very well!!

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[jackjcc]

Huh, I dislike having all the gunk to clean out but I like having all that lube.


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[wde_1978]

Is Your clutch slipping a lot while cutting?
As @buzz sawyer said, the sprocket bearing doesn't really turn 13k once the clutch engages.
Maybe You are over lubing the bearing and the excessive lube ends up in the clutch's friction surface causing/allowing slip?!

I give the bearing a drop of bar lube (mineral oil, NOT BIO!) and there always seem to be some left upon the next inspection/cleaning.
Alternatively You could try some MoS2 lube, although honestly I never tried it as I never felt the need for it and just use a drop of mineral oil.

I think something is not a 100% right if Your saws sprocket bearing gets dry all the time!
I can't comment on other saws, but Your DCS6421 sprocket bearing should NOT dry out after only 2 hours of work - that is about 4 tanks of fuel only, right?!

Seems to be no bar oil getting to it. Could there be an issue with the saw?
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I keep the oil pumps maxed out on my big saws (the little ones have unlimited pumps so maxing out is pointless ), yet I have never noticed bar oil reaching the sprocket bearing!
It actually seems physically impossible as the centrifugal force of 13k rpms drives any excessive oil outward into the drums friction area.
Just saying.

Pictures of what You deem a dry bearing could help.

Like given for a great saw.
Cheers

 

[Flint Mitch]

Is Your clutch slipping a lot while cutting?
As @buzz sawyer said, the sprocket bearing doesn't really turn 13k once the clutch engages.
Maybe You are over lubing the bearing and the excessive lube ends up in the clutch's friction surface causing/allowing slip?!

I give the bearing a drop of bar lube (mineral oil, NOT BIO!) and there always seem to be some left upon the next inspection/cleaning.
Alternatively You could try some MoS2 lube, although honestly I never tried it as I never felt the need for it and just use a drop of mineral oil.

I think something is not a 100% right if Your saws sprocket bearing gets dry all the time!
I can't comment on other saws, but Your DCS6421 sprocket bearing should NOT dry out after only 2 hours of work - that is about 4 tanks of fuel only, right?!


I keep the oil pumps maxed out on my big saws (the little ones have unlimited pumps so maxing out is pointless ), yet I have never noticed bar oil reaching the sprocket bearing!
It actually seems physically impossible as the centrifugal force of 13k rpms drives any excessive oil outward into the drums friction area.
Just saying.

Pictures of what You deem a dry bearing could help.

Like given for a great saw.
Cheers

To my knowledge it isn't slipping. I will use it in the next few days and pull it apart. I'll shoot a few pics

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[Flint Mitch]

Updated with a new thread with a new issue/question

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