Where to get good moly grease (6o% moly or more)

[robmack]

Just picked up a tube of honda moly77 grease that London Honda ordered in for me. 75grams 19$ + tax.

I searched for but couldn't find a MSDS for the M-77 stuff. Spline lube should be very sticky to make sure it continues to work over a long period of time. The pressure exerted by the splines pushes the suspension material of the grease out of the spline, leaving the moly lube behind. That's why you want 60% or more moly content but also a grease with extreme pressure properties. Popular in the BMW K-bike community is to use a 50/50 mix of Honda Moly 60 and Wurth Sig 3000. Read this to understand the reason. Wurth Sig 3000 is unobtainable in Canada unfortunately but a good substitute is Guard Dog Moly 525. If you end up using the M-77 on your splines, check them a bit more often to see if the lube is working as you expect. Worn splines are not cheap to replace but your time to inspect is cheap.

 

[dirtbag]

I wanted to know just how much moly was in this stuff so I called the manf. PolySi Technologies Sanford NC. I talked to one of the techs who explained it has more than 60% moly in a silicone based carrier.

He thought the heat may burn off the silcone, which I thought should leave the moly behind to do the grunt work. Maybe I'm wrong, but I figure it has to be way better than the general purpose grease I used last time ( which likely lead to my badly chewed up splines and the need for replacement of both the diff & wheel).

That said I will likely yank it apart after 5-7K to check on the condition vs having to replace these parts again.

 

[robmack]

I wanted to know just how much moly was in this stuff so I called the manf. PolySi Technologies Sanford NC. I talked to one of the techs who explained it has more than 60% moly in a silicone based carrier.

He thought the heat may burn off the silicone, which I thought should leave the moly behind to do the grunt work. Maybe I'm wrong, but I figure it has to be way better than the general purpose grease I used last time ( which likely lead to my badly chewed up splines and the need for replacement of both the diff & wheel).

That said I will likely yank it apart after 5-7K to check on the condition vs having to replace these parts again.

Some moly will remain behind but it's hard to know if it will be sufficient to prevent spline wear over a long service life. The silicone doesn't have the extreme pressure characteristics needed to retain the moly lubricant in the splines. The rotational forces and pressure will fling most of the grease to the outside of the drive shaft housing or within the drive shaft itself (unless there is a retaining cup built-in) in a short time.

The general purpose grease you used probably did no good and that contributed to the pre-mature wear. The M-77 is better but not as good as Honda 60 or 50/50 honda 60-Wurth Sig 3000.

The recommended service interval for final drive splines on the K-bikes is every other tire change, or about 10K kilometers. It's much longer for the clutch and output shaft splines. Many owners do the FD service more often because (1) its easy to do and (2) it prolongs the service life.

 

[dirtbag]

"The recommended service interval for final drive splines on the K-bikes is every other tire change, or about 10K kilometers." 5k to a tire? I would get 10K on my sporting bikes and my E3 went almost 20.

I don't see the grease being flung off due to rotation since the splined shaft fits into a spline bore which would help retain, or catch it - does make sense?

Thanks for the detailed input Rob. I think for now I'll run the m77 but make sure to yank it apart for service long before waiting for the tire to need a replacement. Maybe next it comes apart I'll be sure to have some Honda60 on hand , for now I'm just chafing to get the bike back together.

 

[robmack]

Oops, typo. Meant to type 20K kilometers. 5k per tire set is pretty low.

I don't see the grease being flung off due to rotation since the splined shaft fits into a spline bore which would help retain, or catch it - does make sense?

That makes sense. Different manufacturers have different designs. The drive shaft on the BMW is hollow all the way through. On the final drive end, grease is pressed out both ends of the spline because of the rotational and sliding motions. Consequently, it's lost to the inside of the drive shaft and flung around the final drive housing, where it does no good. If your shaft has a sealed spline, then the grease will be retained and perform useful work.

BTW, This is about the amount of grease you'll want to use ( Source ):