How much freeplay is "normal" in the spline coupling at the rear wheel (1990 ST1100)

[TerryS]

I've noticed I can hear a metallic clunk from the final drive when I roll the wheel back and forth in neutral on the centrestand. Bike has 130000km, and I've been diligent with the moly paste (Molybond GA50 50% molybdenum disulphide in lithium grease) at my frequent tyre changes (10000km).

From pulling the final drive oil filler cap and observing the crown gear, the noise is freeplay between the wheel and this gear. I have pulled the wheel out and slipped the driven flange out, and if I then put that flange into the spline coupling I can feel that the freeplay is coming from the spline coupling itself. Visually the coupling looks OK to me with square edges and no obvious wear. Once the freeplay is taken up, the wheel rotates really nicely with no noise from the shaft or universal.

So how much spline freeplay is normal? Is it normal to be able to hear the spline clunk when you move the wheel?

 

[Upt' North]

Terry, haven't we been here before about 2 years ago? It could be my dementia setting in.
The answer is I don't know, but logic says not much.
When these parts were new I would expect no noticeable freeplay/lash. When lubed up I would have expected them to slide together easily like a propshaft joint on your ute. You know like that Gay German, Fritz Nice n Tight.
Obviously there must be a gap to allow for expansion and contraction when in normal use. But the gap would be half of bugger all. If it's still rideable lube and ride, I'm not going into the M word. I would personally then be on the lookout for a good secondhand part for next time.
Good luck fella.
Upt'North.

 

[dwalby]

there's so much grease on the final drive female spline its hard to say, but it doesn't look as good as the male spline you pulled off the wheel.

 

[John OoSTerhuis]

I would prefer pictures of the splines cleaned of all moly, but from what I can see, your splines are showing wear. There appear to be “shelfs/steps” formed on the sides of the splines. In extreme cases the wear continues until the splines are completely worn off on the final drive. Some play is normal. Keep using the moly and inspect the splines often. My splines were pristine for years until I noticed a slight shelving on only the final drive at around 140K. I pulled the drive and did the alignment procedure and have had no further wear through 190K. Recommended. FWIW

John

 

[dwalby]

yeah, I see the steps you're talking about, I just gave it a quick glance the first time and thought it was a reflection. A straight-on picture might show the condition a little better. I'm curious to see what's under all that moly.

 

[Jim Van]

Terry: Clean all the moly off all the splines and take another two pics looking straight into the splines. That will give a better view of any wear.

 

[Slydynbye]

I would check all 3 O-rings to make sure they are in place and in good condition.
I had a failure of one O-ring and in under 1000 miles I see wear on the splines with that distinctive step look . I think part of the O-rings job is to hold the splines centered.
Also a clunk can be caused by worn inserts in the Cush drive. Check the aluminum inserts for oval holes.

 

[red one]

Mine has that play too and sometimes I get a little light clunk when moving rear wheel by hand. Shop checked and greased my splines in 2017 when I got new tires, Still does it sometimes.

 

[TerryS]

Thanks for the advice folks. Yes there is a visible step on the drive face of the male spline so I suspect that is the wear causing the freeplay. There is a missing o-ring (the skinny big one on the wheel hub, the other two are in place) so I will sort that. I replaced the cush drive rubbers about 30,000km ago so they are in quite good shape, and the freeplay I noticed is definitely the splines. AFAIK the final drive is correctly aligned as I had the swingarm off/apart last year and followed the procedure.

I have added more grease and reassembled but will keep a closer eye on things. I probably should clean out the female joint for a look-see but that sounds messy; the moly grease does stick like stuff to a blanket!

 

[CYYJ]

Hello Terry:

In my opinion, the splines on the 'spider' (the 'male' portion of the two) look good, I don't see any abnormal wear. Like the others, I can't comment on the splines within the hub because there is too much grease & crap in there.

It's good that you are being diligent about applying Moly paste, but remember that the manual only calls for 3 grams of the stuff - that's about equal to the amount of toothpaste you put on your brush. You only need a thin film covering the mating surfaces.

Here's a link to an article that shows where the three O-rings are. If you have not previously replaced them, you might want to consider doing so - the O-rings keep the Moly lubricant inside, and the moisture and dirt outside. ST1100 - O-rings in the final drive (rear wheel)

When you are measuring free play (backlash) in the system, be aware that there are numerous possible sources, and they are additive. My experience has been that the greatest amount of backlash comes from wear on the 5 rubber pieces that the fingers of the spider fit into. I get about 30,000 to 50,000 miles out of those rubber / metal parts, then they need to be replaced. Next largest source of backlash is where the two splines shown in your photos meet. Finally, there is a bit of backlash within the differential itself, but that is generally pretty minor, and the differential is not known to be a problem so far as wear is concerned.

Michael

 

[CYYJ]

I probably should clean out the female joint for a look-see but that sounds messy...

Get a pair of disposable latex gloves and a box of Q-Tips (cotton swabs), clean it out as best you can with the cotton swabs then go at it with brake cleaner or electrical contact cleaner.

Below is a photo of badly worn splines on the female component, to give you a reference. This happened to my ST 1100 about 10 years ago when an apprentice at the dealership used the wrong lubricant (normal grease instead of Honda moly paste) on the final drive. It only took 10,000 km (6,000 miles) to go from perfectly OK to looking like this. The dealer was ethical enough to replace all the parts at no charge, but I think it cost them well over $1,000 for the parts, and that was in 2008. Note also the evidence of corrosion - the kid didn't replace one of the O-rings (I had specified that all 3 be replaced - he took 3 out, but only put 2 back in).

The moto still ran OK with the splines looking like this - it was in for a tire change when this was discovered. The lubrication error was made during the previous tire change.

Michael

Badly Worn Splines

 

[TerryS]

Thanks for a very detailed response Michael; actually the o-ring is in place on the driven flange, but as you say I have been somewhat "liberal" with my use of grease....

I'm pretty diligent about wearing disposable nitrile gloves as I have spent my working life in a chemical industry. I will have to raid my wife's supplies for the cotton buds however.

 

[DeanR]

There appear to be “shelfs/steps” formed on the sides of the splines.

Agree. Since you replaced the rubbers (inserts as well?) not that long ago, I bet the splines might be what you are feeling, if it it greater than normal.

My experience has been that the greatest amount of backlash comes from wear on the 5 rubber pieces that the fingers of the spider fit into.

Agree, including the aluminum inserts.

 

[habanerobob]

I know this thread is for an ST1100, but I imagine the same would apply to a ST1300. I am a new owner of a 2009 ST1300 with 113,000 kms (70,000 miles) on it and I wonder about the amount of drive train freeplay. When I have the bike up on its center stand, with the bike in first gear, I can rotate the rear wheel approx 2" of rotating circumference. Is that normal? Thanks for any help with a comparison.

 

[Jim Van]

Good question !! I know my splines are in excellent condition and I just checked my ST1100. In 1st gear on the center stand, When I rotate the rear wheel back & forth it moves about 1 3/4 inches at the periphery of the rear tire. That would also account for some slop in the transmission and driveshaft, too. I tried it in second gear and didn't see any change, BTW.

 

[habanerobob]

Good question !! I know my splines are in excellent condition and I just checked my ST1100. In 1st gear on the center stand, When I rotate the rear wheel back & forth it moves about 1 3/4 inches at the periphery of the rear tire. That would also account for some slop in the transmission and driveshaft, too. I tried it in second gear and didn't see any change, BTW.

Thanks Jim - I a

Good question !! I know my splines are in excellent condition and I just checked my ST1100. In 1st gear on the center stand, When I rotate the rear wheel back & forth it moves about 1 3/4 inches at the periphery of the rear tire. That would also account for some slop in the transmission and driveshaft, too. I tried it in second gear and didn't see any change, BTW.

Thanks Jim - I appreciate you taking the time to check your bike as a comparison.

 

[paulcb]

I just changed my rear tire on my ST11. While the tire was getting mounted, I cleaned and lube both the male and female splines. I then took the flange with the male spline and inserted into the female splines. I pulled it out and rotated it a few degrees, back in and out. I repeated this a few times to make sure the moly paste was evenly spread in all the grooves. When the splines were engaged there was very little play between the two, almost none. Therefore, almost all the play at the tire surface is in the driveline upstream of the splines. FWIW, I have a similar about of play, as described my Jim Van above.