My first real problem with my 1993 ST1100

clotter

Joined
Dec 12, 2010
Messages
28
Location
Northeast Wisconsin
Well, I just experienced what I believe may be a major repair to my up until now trusty ST.

Just a little background; from what I've been told, I'm the third owner of this bike. It's been obviously very well taken care of throughout the years, and could still be mistaken for new. It really is that nice. I bought it with around 67k five years ago, and it now has 94k.

I just got back from a 1000 mile trip through Michigan's Upper Peninsula last weekend, so I should consider myself lucky it didn't happen on the trip. Yesterday, I went out for an afternoon ride with my Dad, who was driving his scooter. We got to a country back road that was bordering the property he grew up on as a kid, and decided to stop to chat. We got done chatting, and I put the bike in first gear to take off. All that happened was a rough grinding sound. I put it back in neutral, and tried again. Same thing. No forward movement. Then I put the bike on the center stand and put it in first gear. The rear wheel turned at idle, but I could easily stop the wheel by hand, and hear that the shaft drive gearing was not engaging properly at the rear hub. Ring and pinion gears I guess... The thing is, there was absolutely no prior warning that I was having any issue with the shaft drive. No vibrations or strange sounds, the bike has always been smooth as can be. Anyway, I called my son who brought a trailer, and we loaded it up and brought it to a repair shop. I don't expect them to be able to get to the bike for a couple days yet.

So I'm asking, what could have possibly gone wrong between the time I stopped on the road, shut the bike off, restarted, and tried to take off? :confused:
 
When was the time you looked at the rear splines?
Was moly-60 applied at each tire change?
When the tires were changed were the o-rings in good shape?
 
Just a guess, but your drive splines (in the shaft drive unit) may have finally failed. If they're not lubricated properly they slowly loose the shape of their "teeth". Have never had to repair them so I can't comment on the cost or complexity of the repair work, other than to say they're reasonably accessible so you can get to them easily.
 
Mark, I had the tires changed last fall, by the same place I just brought the bike to. They also changed the tires the time before that. At the time I reminded them about greasing the splines, they made it sound like standard procedure, only they know at this point.

dwalby, thanks for your response too. It's just strange that I went from zero problems or even a hint of a problem, to what I then experienced when I tried to take off. It's almost as if a spring clip or shear pin fell out. Not that I'm aware of such a thing in this setup.
 
Sounds like final drive splines. They don't just go suddenly. Should have been noticed during tire changes. Proper moly paste lube and doing the final drive alignment procedure at the very first sign of spline wear should help arrest it. Do you pull your own wheels for tire R&R or let a shop do it?

John
 
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Somehow this got me 100 miles home when I bought the 91 !!

It actually, somehow, some way, did not feel noticeable, and this is what I found when I got home and pulled the rear wheel. I learned that although it is awkward to request from a seller to pull the wheel, it should probably
always be done with an ST.
 

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Well, the repair shop just called. It is the splines.

John, to your question, I've never taken the tires off. It was always done at the place that now has the bike. Like I mentioned above, I always reminded them about greasing the splines, but have no idea what was actually done when they had it. For what it's worth, they quoted be $660 some dollars in parts, and with the timing belt change (I'm supplying the belt), roughly $1500 complete.

I'm officially having a case of the Mondays....
 
Demand the old parts just to be sure.....
I am really surprised that nobody suggested to inspect the shifter linkage first.
This is why I recommend you ask for the old parts. Some shops quote big bucks for one job when it may be something simple and generate more money for the shop while the customer does not have any idea on the repair really being done.
 
Igofar said:
I am really surprised that nobody suggested to inspect the shifter linkage first.
Click to expand...

The bike shifted between neutral and first gear normally.

Also, he heard an audible grinding noise at the final drive unit when he stopped the rear wheel with his hand, bike on centerstand, engine idling in first gear.

Based on that, I'm curious why you would suspect the shifter linkage over a spline failure?

To OP: all they have to do is remove the rear wheel to show you the visible signs of damage. If you really want to be sure, stop by and ask them to show the damaged parts to you while they're still attached.
 
I have seen alot of st1300's with damaged or rusty linkage thaf would still shift into one gear etc.
I always like to start checking the easy and obvious stuff first.
 
Pay ATTENTION to what Mark said earlier too. The grease used to lube the rear splines HAS TO BE Moly 60 from Honda, or a similar high molybdenum content grease. Anything else and the new splines won't last either.

Pulling the rear wheel is such a simple job that anyone with a few tools should be doing this themselves and then lubing those splines themselves after the wheel with new tire is returned from the dealer. I'm also wondering if the splines really ARE the problem? I'd want to look at them before the dealer goes ahead. Since this happened so suddenly, I'm wondering if the drive shaft U-joint could have failed. The sound of that clunking/grinding around in there could possibly transmit through the swing arm and sound like the rear drive. Maybe??
 
Bush said:
Since this happened so suddenly, I'm wondering if the drive shaft U-joint could have failed. The sound of that clunking/grinding around in there could possibly transmit through the swing arm and sound like the rear drive. Maybe??
Click to expand...

I was thinking the same thing, and thought about mentioning it the first time around. Was waiting for a "splines look OK" reply before progressing to that step, when the dealer came back with the bad splines diagnosis. It is more consistent with the good one minute, bad the next symptom, but I've never had either fail so I didn't want to start speculating on things. One thing I've learned about automotive failures, the cause isn't always what you first suspect, so I hope his dealership hasn't rushed to judgement on this thing.
 
Thanks for all the responses everyone! It's nice to see there's so many knowledgeable people out there, willing to help.

I stopped at the shop on the way home and was able to check out the bike. The manager brought me in back to see the hub, but it was put back on waiting for parts. He then showed me the schematic from the shop manual showing the gear case assembly, and explained that the issue was the splines on the inside of the ring gear. They had meanwhile started changing the timing belt, and had enough off that the engine was open, exposing the belt. I mentioned again, that I wanted the cooling hoses changed. I also brought up the moly grease, about three more times, to at least make sure it gets greased properly now. Who knows if they ever greased it when they changed the last two rear tires... water under the bridge at this point.

I'm going to ask for the old parts back, like Igofar mentioned. Hopefully I'll be back on the road next weekend.
 
DeanR said:
They opened up the final drive?
Click to expand...

If they haven't yet, they will have to when they want to get that ring gear out. SHUDDER!!! Not a job for the unqualified for sure, so I hope the OP has complete faith in this dealership.

Just to throw more fuel on the fire - I would have thought the ring gear splines were a harder material than the matching spider splines, to make the spider the sacrificial part?
 
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Bush said:
I would have thought the ring gear splines were a harder material than the matching spider splines, to make the spider the sacrificial part?
Click to expand...

that's the mechanical engineering view, but the project manager and accountant view was probably to make them both as cheap as possible and let the chips fall where they may (literally). Although, the 1100 was designed a long time ago before severe cost cutting became a universal way of life, so I may be posing an overly pessimistic design scenario.
 
dwalby said:
that's the mechanical engineering view, but the project manager and accountant view was probably to make them both as cheap as possible and let the chips fall where they may (literally). Although, the 1100 was designed a long time ago before severe cost cutting became a universal way of life, so I may be posing an overly pessimistic design scenario.
Click to expand...

The 'cost cutters' began sneaking into Honda right after Mr Honda relinquished leadership (1984?). Prior to that HE was the main driver behind Honda's reliability drive that made the bikes famous worldwide. Now, everything has taken on the MBA flavor of compromise.
 
Just reporting back to let all you fine folks know how things went on my ST. The issue was definitely the splines, there wasn't much left to them. All I can think of, is that the very end of the male splines, and the very inside end of the female splines must have still been meshing. It's the only way these were transmitting any power. When I stopped the bike, and got off, something must have caused the two pieces to shift just enough that the good teeth were no longer meshing. The ring and pinion gears looked like new yet.

In the end, these parts were replaced, and the timing belt was replaced, setting me back $1500.00. It's just good to have the bike back. BTW, it doesn't drive any different with the new splines, than it did the previous 30,000 miles I put on it. I guess an eighth inch of meshing gears can make all the difference in the world!

These are the photos of the parts replaced:

2015-08-29 10.17.03.jpg
2015-08-29 10.16.50.jpg
2015-08-29 10.17.53.jpg
2015-08-29 10.16.33.jpg

And the timing belt after 95,000 miles:
2015-08-29 10.19.35.jpg
 
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