Where did the recommendation for Honda M-77 Assembly Paste start?

[Kevin_56]

But to do a "worst case" analysis when calculating the maximum pressure that the moly has to withstand, only two splines engaged should be assumed - 180 degrees apart.

Here we go - Assumed - that word can be broken down into 3 words, to keep from getting this reply axed I will say - it means no facts to back it up. Why 180° apart, why not 90°? Modern machining techniques have a greater repeatably to produce mating parts that will engage the faces of the splines ensuring that the majority of teeth are engaged. 100% engagement, not likely, but more than 6% if only 2 teeth of 32 are touching very likely.

As stated before, there is photo proof of the wrong paste/grease or none is very detrimental to the splines. So regardless of how many teeth are engaged, paste the devil out of the splines with the Honda Moly60 if you have it, or another Moly that has been "tested" by our members here and has not ruined their splines.

 

[Kevin_56]

Maybe a BSME or MSME can clear this up.

I am working on that. If you can trust an engineer in change of gear hobbing and broaching for John Deere Tractor works, I am waiting for his call back on this discussion.

 

[dwalby]

Jim,

yes I did take a materials course in undergrad, but it was so long ago steel hadn't been invented.

But regarding your worst case scenario, if they can't count on more than two splines being in contact then they'd design it with a lot less splines. Why have so many spline surfaces if its not practical to get them to engage properly? If they knew in advance that the spline pitch was impractical for typical machining tolerances they would have used some other design.

 

[Kevin_56]

Well I got my call back. Without him knowing the design of the spline, as in geometry shape, he could only make an educated guess. His worse case was 80% engagement of teeth. Best was close to 100% based on spline design.

 

[dwalby]

Here you go Jim,

https://www.powertransmission.com/issues/0214/spline-couplings.pdf

Look at the last few pages you'll see the conclusion that even as the tolerances get pretty large there is 50% engagement of the splines. It also maintains 100% engagement for a certain amount of tolerance. Given that we have no idea what the Honda tolerances are, I'm not claiming this to be the final authority on the subject, but I think it suggests that only expecting 2 of the splines to be engaged is beyond worst case. Their test case used 30 splines, that may be the same number as the ST splines, and may be a common spline orientation.

 

[W0QNX]

Three questions: 1.) How close to the ocean do you live ? 2.) Do you believe the mechanic ? Did he bother to grease the splines ? ( They look awful dry. ) 3.) Does the mechanic smoke those funny little cigarettes while he works ?

If you had as many miles on Valkyries as Savago or myself you would know those are all practically irrelevant questions. Be glad the ST1100 doesn't eat splines like a Valk since it uses the same hub as a Valkyrie. It can happen in under 4,000 miles if the o-ring's break or yoou don't hold your mouth right during a tire change. Been there done that 2 times.

 

[Scooter]

That would be perfection. In reality, more than two splines would take the load, but not equally. But to do a "worst case" analysis when calculating the maximum pressure that the moly has to withstand, only two splines engaged should be assumed - 180 degrees apart. And , in reality the only way all splines would be equally engaged is if the machining was perfect and matched between the inner & outer splines - an impossibility in reality.

Worst case analysis also means making reasonable assumptions about what to consider for worst case. I would think that only two teeth out of 26 making contact at any given time is hardly reasonable.

Well I got my call back. Without him knowing the design of the spline, as in geometry shape, he could only make an educated guess. His worse case was 80% engagement of teeth. Best was close to 100% based on spline design.

Even assuming a worst case 80% engagement of teeth, the fact that the loads (driveshaft, suspension, etc.) are constantly changing, you end up spreading that load over all of the teeth. Look at pictures of destroyed splines. You still see even wear across all of the teeth.

I can tell it's wintertime around here. There's always one thread that takes on a life of it's own and appears that for this year this is the one...

 

[Jim Van]

Jim,

yes I did take a materials course in undergrad, but it was so long ago steel hadn't been invented.

But regarding your worst case scenario, if they can't count on more than two splines being in contact then they'd design it with a lot less splines. Why have so many spline surfaces if its not practical to get them to engage properly? If they knew in advance that the spline pitch was impractical for typical machining tolerances they would have used some other design.

Doug : What about cast iron and bronze ? Was that stuff around yet at that time ?

I think some of you guys are missing the point I was trying to make. Re-read the previous posts to mine. The question was, " is a 300,000 psi paste rating" good enough for our splines. If we assume only two splines are mating and the psi calculation then comes out to be less than 300,000 psi, then the 300,000 paste is definitely good enough. I never said I believed only 2 splines are ever engaged, only to use that assumption for the calculation. But you never know........

Thanks for the link, Doug. I'm not surprised that "the total load is not equally shared among all spline teeth" . That's fairly intuitive, even to an EE. Like I said in a previous post, the machining would have to be perfect for the loading to be equally shared.

OK, I have skimmed the article and here are some high points for me :

"Analytical and experimental studies done by Tjernberg (Ref. 3) showed that about half of the spline teeth carry load because of spacing errors, " and "Chaplin (Ref. 1) also recommended assuming that half of the teeth share the full load." and " Volfson (Ref. 6) suggested that about a quarter of the teeth carry the full load." All on page 42.

A nice explanation of what actually happens, due to the different gaps resulting from imperfect machining :

"When subject to gear loads, the pair of mating spline teeth with the smallest gap comes into contact first and load is transferred through it, resulting in elastic tooth deflections. Those deflections cause the gaps between the other spline teeth to get smaller and eventually other pairs of teeth come into contact and share the load. The final number of teeth in contact and their load sharing depend on the gap distribution, the elastic deflections and the load applied. " From page 43.

I'm really curious to know why Valks seem to be so hard on splines.

 

[Ltimb]

So in conclusion, this answers everything........ BUT WAIT, there's more.... If the teeth taking on a greater amount of the load would they wear down slightly? Thus distributing the load to the other teeth? And go.....

Doug : What about cast iron or bronze ? Was that stuff around yet at that time ?

I think some of you guys are missing the point I was trying to make. Re-read the previous posts to mine. The question was, " is a 300,000 psi paste rating" good enough for our splines. If we assume only two splines are mating and the psi calculation then comes out to be less than 300,000 psi, then the 300,000 paste is definitely good enough. I never said I believed only 2 splines are ever engaged, only to use that assumption for the calculation. But you never know........

Thanks for the link, Doug. I'm not surprised that "the total load is not equally shared among all spline teeth" . That's fairly intuitive, even to an EE. Like I said in a previous post, the machining would have to be perfect for the loading to be equally shared.

OK, I have skimmed the article and here are some high points for me :

"Analytical and experimental studies done by Tjernberg (Ref. 3) showed that about half of the spline teeth carry load because of spacing errors, " and "Chaplin (Ref. 1) also recommended assuming that half of the teeth share the full load." and " Volfson (Ref. 6) suggested that about a quarter of the teeth carry the full load." All on page 42.

A nice explanation of what actually happens, due to the different gaps resulting from imperfect machining :

"When subject to gear loads, the pair of mating spline teeth with the smallest gap comes into contact first and load is transferred through it, resulting in elastic tooth deflections. Those deflections cause the gaps between the other spline teeth to get smaller and eventually other pairs of teeth come into contact and share the load. The final number of teeth in contact and their load sharing depend on the gap distribution, the elastic deflections and the load applied. " From page 43.

 

[dwalby]

Jim, we're not missing your point at all, we're just disagreeing with you about your assumption of what's a reasonable worst case analysis. Assuming 50% of the splines are in contact would be a reasonable worst-case, and the link I shared would support that value. Assuming only 2/30, or 6.67% are engaged just isn't reasonable.

Also, without knowing what percentage of each mating surface is actually in contact, its a losing battle trying to calculate the psi load. Let's say the spline tooth is 1/8" tall, the fact that its tapered and in contact with another tapered surface means we can't assume the entire 1/8" is in direct contact (or isn't). If only 25% of that 1/8" is actually in contact, that's a 4x difference in psi value, and how far do you take that variable, 10%, 50%, 90%???

my own empirical evidence shows that if I put some moly paste on the splines every few tire changes, that seems to have worked out OK for me, so the psi rating on the moly is the last thing I'm worried about. When I didn't have a tube of moly on the shelf I often went several tire changes without doing anything at all other than put the wheel back on the bike. Then a random tire changer would slap some on the splines for me and I'd be good for a few more changes.

 

[Jim Van]

Doug : Read the article. It says that the load will cause deformation so the entire tooth will have contact, but the load will not be uniform across the tooth, of course.

I would still do a calculation assuming only two teeth in contact. Call it a worst-case, worst-case analysis. I would want the result to be < 300,000 psi so I could sleep like a baby at night, not worrying about whether the paste I'm using on my splines is good enough. And paste is cheap compared to replacing the splined components, even good used parts off EBay. After all, I'm retired and on a fixed-income and saving for a good used 2018 DCT GW hopefully purchased in 2020 , with approval of the family CFO.

 

[BakerBoy]

Interesting thread. Must be winter.

BSME, MSME here.

'Film strength' is not a lube yield stress or a compressive stress that a lube can be put under in service (tolerable hydrodynamic pressure is much less than purported 'film strength'). Film strength is a calculated number from a very crude (and questionable) Falex Test that drags the lube into a joint where the surfaces have high sliding velocities relative to each other (not a stationary joint, such as for splines). Even the term 'film strength' is a misnomer.

The Falex Test is not applicable for moly paste in a stationary joint, however it provides wonderful hocus pocus data for marketing types to claim a high film strength number. You can find lots of such 'film strength' data by lube manufacturers--it isn't proof and should be taken with a grain of salt.

There is no fitting test that I know about for paste in stationary joints as the effectiveness of the lubrication is highly dependent on the joint itself and not solely on the paste (as long as the paste is present in sufficient quantity). Also of importance in the case of moly paste is the particle size of the moly-disulfide--yet that data isn't reported that I know of for any such moly paste or lube. Moly particles are very hard and dense (more so than the steel of a spline tooth), and if the moly particles are relatively coarse the contact surfaces can wear much quicker.

Regarding the well-beaten subject of spline teeth count that can be expected to be in contact: it approaches 100% of teeth, all of the time, if the parts are built to print and the joint stays lined up. Any slight high point on a tooth wears down very quickly and is actually beneficial so that the load is always spread to all the teeth. I've yet to see a spline (ST1300) where NOT all of the teeth were in contact. But all that is moot.

The moly paste in a spline squeezes out of the contact surface when load is applied (when accelerating the bike for example)--it is squeezed back in when load is reversed and the backside of the tooth is taking the load (when decelerating the bike for example). The more volume there is for the paste to squeeze out (such as for well-worn splines), or the less the paste there was applied, the less lube there is that squeezes back and forth onto the tooth contact area.

Points:
1) The more the spline wears, the faster it wears. So, if you've a worn spline, don't transmit high power through it. Also ensure the 6905 driven spline bearings are good because they are what keeps the spline aligned (and hence why the 6905 bearings easily fail in this application).
2) Use ample paste whenever working the splines (there's reason to not be miserly), making sure every tooth's front-side and back-side are coated, and make sure the O-rings are in good condition so that the moly paste isn't leaked outside of the spline joint during service. The rule of thumb to "don't over-pack grease in bearings; leave 30-50% air space in the raceway" does NOT apply to paste on splines.
3) Use fresh paste every time and clean off any dried paste from the splines--not because the moly-disulfide has lost it's capability, but because the carrier paste is no longer flowable to be squeezed back and forth across the tooth onto the contact surfaces between acceleration and deceleration.
4) Just because there's paste slung on the driven flange outside of the O-rings doesn't mean there's a problem. It can mean the O-ring is damaged, or it can simply show that plenty of paste was used. My ST1300 always had the paste slung on the driven flange because I used the paste amply and some of it inevitably ended up smeared outside the O-ring as I worked to put the wheel and axle back into the bike--there was always still flowable paste on the splines when the wheel was removed for tire changes and that's what matters.

Perhaps I missed it, but I'm still stuck on the premise of the thread. So I ask: "What source shows that Honda officially recommends M77 assembly lube in lieu of M60 paste? Is there a Honda Service bulletin?" Keep in mind that the use of assembly lube has always been a shortcut by shops, even years ago when M60 was easy to acquire. Now, with Honda M60 no longer available, even shops who follow the book have to use something.

 

[MajorTom]

I'm really curious to know why Valks seem to be so hard on splines.

Well you know what they say, "There are no bad bikes, just bad riders."

 

[Upt' North]

[FONT=&quot]World famous Molykote M77 direct from the Honda supply chain, formulated specifically for Honda and Acura vehicles.[/FONT]

• Contains MoS2
• Resistant to chemical oxidation and radiation
• Protects against fretting corosion
• Replaces Pro Honda Moly 60 08734-0001

I think that's kinda like from the horses mouth, I don't believe everything I read but it's pretty clear to me.
With regards Baker Boy's lengthy and enjoyable analysis of the whole issue he alludes to wear in of components and correct lubrication to achieve the same. The splines on the shaft are no different to the gears in the box or the bearings on the crank; they all start off pretty rough (relatively speaking) but with careful running in and correct lubrication all is mated together nicely over time. All gears will mesh, that's what they do, if only two were working they wouldn't get the bike out of the showroom.
FWIW.
Upt'North.

 

[dwalby]

Jim, regarding the Valkyrie spline failure rate, one factor may be the 100 ft-lb torque of the Valkyrie vs. the 80 ft-lb of the ST1100. IIRC someone mentioned in an earlier post that both bikes use the same spline components. The Valk may be running at the ragged edge of acceptable power transmission through that spline design while the ST has some headroom. Just a guess.

p.s. thanks BakerBoy for the interesting read.

 

[ST Gui]

•Contains MoS2
•Resistant to chemical oxidation and radiation
•Protects against fretting corosion
•Replaces Pro Honda Moly 60 08734-0001

I think that's kinda like from the horses mouth, I don't believe everything I read but it's pretty clear to me.

Where did you find this nugget?

 

[Upt' North]

StGui, you'll find it on H-Tune web site, supplier of genuine Honda Products etc. UK site, I would post a link but I'm stupid!
States clearly that it's use is for gears in high pressure/temperature settings.
I personally use it and it works fine. Doesn't fly off and keeps splines in good shape.
Also worth considering re excessive spline wear, how often do folks change tyres. In UK they're shot at about 5K miles and my splines will have been lubed every 5k and a total of 55K.
Again, FWIW.
Upt'North.

 

[Andrew Shadow]

StGui, you'll find it on H-Tune web site, supplier of genuine Honda Products etc. UK site, I would post a link but I'm stupid!
Upt'North.

Where did you find this nugget?

It is from this website- Replaces Pro Honda Moly 60 08734-0001

This same claim coming directly from an official Honda information source as opposed to an independent retailer who carries Honda parts would probably be more satisfying to most here I would suspect. Having said that I find that often most websites seem to have the same descriptions attached to a given part which would indicate that the text probably comes from Honda anyway.

 

[Upt' North]

I agree Mr.Shadow, it seems to be a straight lift from Honda Technical, no one is going to sit down and right this nonsense, are they?
I wouldn't rely on Joe Bloggs qoutes on eBay or other perveyour of fine products, but Honda specialist suppliers is I think as good as it gets.
Upt'North.

 

[ST Gui]

This same claim directly from an official Honda information source as opposed to an independent retailer who carries Honda parts would probably be more satisfying to most here I would suspect.

Agreed. It would be unequivocal which is always good for bar bets. But even without such a blessing it's odd that among the line of Honda branded and Honda 'approved' lubrication products they sold M60 then dropped it and now sell M77.

It's even odder when you consider M60 met their own requirements of 'spline lube' and that M77 doesn't (?).

In UK they're shot at about 5K miles and my splines will have been lubed every 5k and a total of 55K.

As with most things it seem regular and timely maintenance is just as if not more important that which of these two products is used.