[Arizoni]

I believe the change in the direction of the threads on the output end of the crankshaft was due to the bolt that became unscrewed and jammed between the rotating clutch housing and the left engine housing.

This did not happen to a new "from the factory" engine.

This occurred in India following a electric starter clutch replacement and there is a good possibility that the true cause of the bolt unscrewing is that the mechanic forgot to properly tighten and torque the bolt.

Bearing in mind that there are thousands of the new UCE powered bikes in the world and I have not heard of another similar accident I think it would be foolish to remove the existing bolt to apply some thread locking compound in the interests of just being safe.

[Ducati Scotty]

Bearing in mind that there are thousands of the new UCE powered bikes in the world and I have not heard of another similar accident I think it would be foolish to remove the existing bolt to apply some thread locking compound in the interests of just being safe.

I've heard of two, one here and one elsewhere, but yes, not a systemic problem or we'd hear about it more.

Thanks,
Scott

[Arizoni]

I believe the one posted here is the same one posted on Team BHP but I might be mistaken.

Once I thought I was wrong but I was mistaken. 

[Ducati Scotty]

So then maybe it's just one.  Sounding more like mechanic error every day.

Scott

[Arizoni]

As I say, I may be mistaken about the number of these events.

It is pretty hard to believe that Royal Enfield would go to all of the trouble to create a new crankshaft with a left hand thread being the only change.

If they work like my old company did that would involve at least five drawings and drawing numbers.

The new LH bolt design.

 The new drawing for the output end of the crankshaft with the LH threads.

The assembly drawing of the crankshaft/connecting rod/bearings to call out the new part number of the crankshaft end.

The engine assembly parts list to call out the new crankshaft and the new bolt numbers.

The revised Motorcycle assembly to call out the new engine part number if one is created to define this revision.

They would probably maintain traceability of this change by recording the first motorcycle to incorporate the revised engine changes by serial number.

This kind of traceability is a PITA for us owners.  We order a part and receive it only to find that it is the wrong one.
That's when the parts man says, "Oh!  You didn't tell me your motorcycles serial number was newer than XXXXXXXXXX5!"