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Moly

David919

David919

Ride Again!
Joined
Dec 10, 2015
Location
Livermore, CA
Moto(s)
2005 Honda 919
Name
David
BARF perks
AMA #3283700
molybdenum disulfide oil, so any one out there, with several valve clearance checks and reshims under their belt, want to let me know what they think about oil/dry versus wet/grease in this application? Honda service manual says use oil, but in the process of looking for some I see a lot more grease than oil, so got me wondering. I’m hoping there will be the usual no shortage of opinions. Thx
 
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David919 said:
valve clearance checks and reshims under their belt, want to let me know what they think about oil/dry versus wet/grease IN THIS APPLICATION? Honda service manual says use oil,
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This^^^^
 
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"valve clearance checks and reshims" does not make it clear what u want to apply moly to.

I don't oil anything when I do a valve adjustment. the valves, shims, cams, etc are already coated in oil.
 
It says, “Install the newly selected shim on the valve retainer. Apply molybdenum disulfide oil to the valve lifters. Install the valve lifters into the valve lifter hole”.
Thank you, you’re reply is the kind I’m looking for, importance of putting it on and or/if there is a practical difference between the two products. I’m a commercial equipment mechanic and never done a moto valve check or reshim. My compressor rebuilds have never asked for additional/different lube on anything. Any info. is good info at this point.
 
fast4d said:
paper oil filter will stop moly cold.
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From what I’ve read today, supposedly, the moly coats and impregnates any porous surface and isn’t easily flushed away, providing improved lubrication. True or not, necessary or not, I don’t know. I’m inclined to get th oil and do it like it says just to be sure, I didn’t know if someone had practical experience with the grease being better or worse. Seems to me if the tolerances are tight in this area grease might actually inhibit oil passage.
 
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The moly is to prevent new parts (or old parts shorn of any oil during the repair) from running dry while the flow of oil gets back up to the top end.

I don't know what the manual says but when I replace shims on my DL650 (I have to pull the cams) I put a tiny dab of Lucas Assembly Lube (moly based oil) on the shims, buckets, cam lobes and journals on assembly to insure it doesn't run dry on first start.
 
dmfdmf said:
The moly is to prevent new parts (or old parts shorn of any oil during the repair) from running dry while the flow of oil gets back up to the top end.

I don't know what the manual says but when I replace shims on my DL650 (I have to pull the cams) I put a tiny dab of Lucas Assembly Lube (moly based oil) on the shims, buckets, cam lobes and journals on assembly to insure it doesn't run dry on first start.
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Sounds good, thx
 
moly is meant to be used on NEW engine/parts assembly.

I used it when I built a 302 stroker. However IMO it really wasn't necessary as I primed the oil pump through the distributor drive gear.

the engine got oil pressure and hand rotated before initial start up and run in.
 
FWIW, I just looked it up in my Suzuki service manual and for the DL650 they recommend a dab of motor oil on the shims and moly on cam lobes and journals on reassembly after a valve adjust. I don't think moly on the shims will hurt anything and will eventually get flushed out. It is compatible with all engine oils so no harm there either.

One advantage of the Lucas Assembly Lube is that it is tacky so it sticks to the parts and doesn't run off like motor oil would so it stays in place until you are ready to fire up the bike. The stuff is cheap at ~$6/4oz and you don't need much. My 4oz bottle is still 3/4 full after +5 years. I also use it on a few frame bolts that tend to seize.

Also, when I change the oil/filter or do a valve adjust I unplug the crankcase position sensor (so the motor won't start) and crank the engine a few times to prime the oil pump, filter and misc. passages as an additional precaution.
 
Moly (molybdenum disulfide) is an inert, dry sub micron size powder that has remarkable lubricating properties. It can handle incredible pressure and heat and because the partial size is so small, it can work itself into the microscopic pores of many materials like metals and plastics. That's why it's used extensively to treat metal surfaces subject to friction and is used in a vast array of oils, greases, pastes and other lubricants. It is even applied dry. And it is used by just about every engine manufacturer when an engine is first put together.

Because of these properties, it can be used for a wide variety of things. I wouldn't hesitate to use it when putting new shims in. It's perfect for the job and will treat the wear surfaces of the new shims (or old ones) to reduce wear. I'd also put a light smear on the cam lobes. Don't goop it up, just a light smear.

I also use a thick paste of moly applied with an old, short bristle artist's paint brush to the threads I screw into aluminum alloy. Yes, it will alter the torque required to secure the fastener but I almost always use my educated wrist rather than a torque wrench.

Even better than moly is tungsten disulfide. The only reason tungsten disulfide is not as popular as molybdenum disulfide is that when their lubricating properties were first discovered and they began to be used commercially, tungsten was much more expensive than molybdenum so the cheaper element was used. Now, tungsten disulfide is in the same price range as moly so that's why I recommend it over moly. Note, though, that the commercial market for tungsten disulfide hasn't caught up with the moly market and therefore there are fewer products available. You can mix your own, though, as both are easily available for purchase. You can even buy either on Amazon.

I have a can of this for spraying it on:

https://www.amazon.com/LOWER-FRICTI...647&sr=8-5&keywords=tungsten+disulfide+powder

And I have the raw powder as well.
 
fast4d said:
paper oil filter will stop moly cold.
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Wrong.

The vast majority of oil filters for cars, trucks, and motorcycles will filter down to 25 microns with about 98% efficiency. That's about the best they can do.

Typical micron size for moly is 1 to 1.5 microns. No way it's going to filter moly out of the oil.

And tungsten disulfide particle size is typically about 0.5 microns, half that of moly.
 
maybe technology has improved in the 20 years since I was into engine building. just like it has for motor oil.

oil filters going into bypass mode or oil pressure drops with liberal use of moly assembly lube was not unheard of.
 
When moly paste clumps up, there is no telling how big the clump is. I would think it would be larger then 25 microns.
 
Moly is just for breakin so you dont flatten the cam on start up. If you want to run moly, they make oil called Lubromoly that has moly in it. Used to run it in my mercedes.
 
Honda specifies putting moly paste on the final drive splines when changing the rear tire on a Goldwing - apparently it holds up better than regular grease when used in certain applications.
 
Alan_Hepburn said:
Honda specifies putting moly paste on the final drive splines when changing the rear tire on a Goldwing - apparently it holds up better than regular grease when used in certain applications.
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Applies to all shaft drive bikes with drive spines. Don’t do it and you destroy your final drive.
 
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