The skies were clear and the temperatures were warm, perfect riding conditions.
We were cruising at around 55 mph down CO 85 aka Parker Road towards Franktown when all of a sudden (no warning noises or sensations) the rig lost power and I could hear the clutch disk slipping.
I quickly pulled off to the side of the road and initially, it looked like the donut was spinning (all kinds of rubbing/spinning noise at this point) but no forward motion so I thought the drive shaft splines had worn off where they go into the donut yoke.
This by the way, is an expected event. The rig's drive shaft came with the old type "fine" splines used to mate up to the yoke on the donut which transmit power from the gearbox. I even have the new "coarse" splined drive shaft on hand and ready to be put in.
I pushed Fiona down the slight hill that I stopped on and moved her to a spot alongside a dirt trail out of the way of traffic on Parker Road and called my son Miles.
Miles and his friend Travis got the trailer hooked up to the PT Cruiser and shortly before 11AM they were there and we got Fiona up on the trailer and tied down.
While I had been waiting, I did some more troubleshooting and determined it wasn't worn off splines on the drive shaft. Damn. It was looking like possible a gearbox issue and probably a clutch disk issue as well. The noises being made with the gearbox in gear sounded very much like when the clutch disk splines on Scarlett failed. Damn.
We got Fiona home with no issues and about an hour later I had removed the pusher wheel, final drive and gearbox to take a look.
First major issue, the splines were completely gone from the BMW clutch disk! It looked, just like in Scarlett's case, like they'd been machined off:
splines were completely missing!
Here's a picture of the new clutch disk when I installed
over a month ago, note the splines.
So that explained the spinning noises of course. But what caused the splines to be worn off? The gearbox input splines were looking pretty bad as well. These are the splines that mate up with the splines in the clutch disk above in order to transmit rotational power from the engine.
Pretty chewed up eh?
Below picture is of the same input splines as they looked
when I got the rig from the previous owner.
Not looking that great to start with eh?
I had also drained the oil from the gearbox and it came out the color of Olive Drab Green. So there was water contamination as well. Apparently, the rubber boot that I thought was there to seal the hole where the speedometer cable goes is just there for looks. I'll be using some liquid tape to seal it off when it's re-assembled.
No big chunks of metal but plenty of metal "sparkles" in the oil pan so something has become damaged inside the gearbox. The suspicion is that the rear main bearing for the main shaft in the gearbox had failed, coincidentally, the same bearing that had recently failed in Scarlett's gearbox.
When you turn the yoke at the rear of the gearbox or the input shaft itself by hand, you can feel a clicking or "notchiness" while turning. This is not a good thing.
The theory right now is that the bearing failed, perhaps causing undue stresses on the main shaft which were transmitted through the splined connection to the BMW clutch disk splines, eventually wearing them away.
I cleaned up the gearbox, will drain it overnight and package it up for shipment to North Carolina and Richard Winter who's going to check it out and replace what needs replacing. He wanted to also check the custom welding work he'd done to ensure the previous owner had not bent something while mounting/dismounting the gearbox.
If there was some bending of the mounts, that would also cause the input shaft to not be "true" as it mates with the clutch disk splines, causing the existing damage.
Since I'll not be doing much riding on my motorcycles next month, I'm not very bummed out at these mechanical failures. Sure, it'll cost money to have Richard Winter fix things right but then I'll know they're corrected and the gearbox is in good shape. I'll also be getting a replacement BMW clutch disk from Richard to replace the stripped out one.
Any sidecar riding that needs to be done before June, will be done on Scarlett, my 2014 Ural Patrol rig. I do need to swap the muffler on Scarlett but that's minor work and the subject of a different posting.
Ah, the vicissitudes of the life of a Uralista.