A little mechanical excitement

[Cormanus]

Being a mechanical klutz, I send the bike to a mechanic for anything non trivial.

It's approaching 120,000 kms now and the valves have not been inspected for the past 30,000+ kms, the brake and clutch fluid need changing, my BT31s are at the end of their useful life (nearly 18,000 kms), and I need a new chain and sprockets after 43,000+ kms.

The bloke I've been going to has moved on to other things, so I found a local chap—which is good because I can walk home after dropping the bike—and left the bike with him late on Wednesday so they could do everything on Thursday.

About 3.00 pm on Thursday I got a telephone call from the workshop and, even while we exchanged pleasantries, I could tell the news was not going to be completely good. After a brief conversation and dispensation from my wife, I leapt (in my dreams) in the car and went around.

The "special bolt" (part #90037-422-003) and accompanying washer (part #90459-438-000) had worked their way loose from the end of the countershaft comp (part #23220-MGC-000) and vanished somewhere along the road. In so doing, they'd punched a hole in the Cover Assy., L. RR. Crankcase (part #11650-MAZ-010) and allowed the sprocket (part #23442-MS2-610) to slide in and out along the countershaft.

The top of one of the internal screws (part #90118-MR1-000) had been partly ground away by the chain and it looks from the photos below like the chain (which was to be replaced anyway) sustained some damage as well.

Here (courtesy of the mechanic who worked on the bike) are some pictures for your entertainment.
[url=https://postimg.cc/c6ZQyBpB]

[url=https://postimg.cc/rzJ58tcX]

[url=https://postimg.cc/Tp3ghYYy]

[Randy B]

Soo.....he replaced the chain and then this happened? That means that all of this repair is on him?

[flynrider]

Yikes! That's a serious looking hole in the sprocket cover.

Would it be safe to assume that these are not the original sprockets? My guess would be that whomever installed that countershaft sprocket the last time possibly did not torque it to spec.

With that sprocket and chain wobbling back and forth on the countershaft, I'm surprised that you weren't able to feel or hear it when metal rubbed metal.

What a bummer, Cormanus! Hopefully this will not cost you too much financial pain. Since you were already going to replace the chain and sprockets, it looks like the only extra parts you'll need are the cover, bolt, washer and screws.

[Cormanus]

Soo.....he replaced the chain and then this happened? That means that all of this repair is on him?

No. Someone else replaced the chain just under 2 years and 43,000 kms ago. I doubt I could land it on him.

Yikes! That's a serious looking hole in the sprocket cover.

Would it be safe to assume that these are not the original sprockets? My guess would be that whomever installed that countershaft sprocket the last time possibly did not torque it to spec.

With that sprocket and chain wobbling back and forth on the countershaft, I'm surprised that you weren't able to feel or hear it when metal rubbed metal.

What a bummer, Cormanus! Hopefully this will not cost you too much financial pain. Since you were already going to replace the chain and sprockets, it looks like the only extra parts you'll need are the cover, bolt, washer and screws.

It is.

Yikes! That's a serious looking hole in the sprocket cover.

Would it be safe to assume that these are not the original sprockets? My guess would be that whomever installed that countershaft sprocket the last time possibly did not torque it to spec.

With that sprocket and chain wobbling back and forth on the countershaft, I'm surprised that you weren't able to feel or hear it when metal rubbed metal.

What a bummer, Cormanus! Hopefully this will not cost you too much financial pain. Since you were already going to replace the chain and sprockets, it looks like the only extra parts you'll need are the cover, bolt, washer and screws.

They are the third set of sprockets on the bike. I guess not torquing it to spec is a possibility.

Yikes! That's a serious looking hole in the sprocket cover.

Would it be safe to assume that these are not the original sprockets? My guess would be that whomever installed that countershaft sprocket the last time possibly did not torque it to spec.

With that sprocket and chain wobbling back and forth on the countershaft, I'm surprised that you weren't able to feel or hear it when metal rubbed metal.

What a bummer, Cormanus! Hopefully this will not cost you too much financial pain. Since you were already going to replace the chain and sprockets, it looks like the only extra parts you'll need are the cover, bolt, washer and screws.

Yes, me too. I've had trouble with the chain for a while. I think it may have had a tight spot and, if it wasn't really well lubed, it would lunk a bit as I took off. I think the bolt has only dropped out recently. I have a vague recollection of hearing a knock, like I'd flicked up a slightly larger than usual stone. As nothing else seemed to happen, I thought little more about it. Fortunately, I don't think there's much room for the sprocket to move on the countershaft as the cover sits pretty close in. I should though have heard some metal on metal. Better get a hearing test as well.

Yikes! That's a serious looking hole in the sprocket cover.

Would it be safe to assume that these are not the original sprockets? My guess would be that whomever installed that countershaft sprocket the last time possibly did not torque it to spec.

With that sprocket and chain wobbling back and forth on the countershaft, I'm surprised that you weren't able to feel or hear it when metal rubbed metal.

What a bummer, Cormanus! Hopefully this will not cost you too much financial pain. Since you were already going to replace the chain and sprockets, it looks like the only extra parts you'll need are the cover, bolt, washer and screws.

Fortunately its not too bad. The bolt and washer are reasonable; the cover is a shade north of AU$200 which seems a little rich to me. I suppose I'll have to replace it so there's something to catch the next bolt.

[Django]

Hm, so there was that hole in the cover and you didn't notice it?

Glad nothing worse happened.

[noroomtomove]

When a cover assembly is behind a cosmetic plastic moulding it could be thought of as being concealed unless disassembly is engaged in.

So now the chain quirk is resolved, good to catch up last week.

Regards NRTM

[Razor]

Cormanus, as an alternative to replacing the cover; I’m sure someone could weld the hole.

As a suggestion. Drill out a piece of aluminum with a hole saw, just larger than the hole. Trace the “slug” from the hole saw onto the cover. Carefully make it so the slug just fits. Weld the slug in place.

[Cormanus]

Django, it’s the inner cover and not normally visible.

Noroomtomove, I’m not sure that was the chain problem. It happened after I got home, I think.

Razor, thank you!

[Rocky_imp]

WOW, that's very shocking! Who would have guessed that something like that could happen!
I'm impressed at the km's you have put on that bike

[the Ferret]

Blimey, that's a shocker for sure.