So is this wheeze - CLACK, wheeze - CLACK more likely to be the auto decompressor or the sprag? (a word I have heard but don't fully understand)
It's happening more and more, and embarrassed the hell out of me yesterday when I tried to get off the Dartmouth ferry! I thought it wasn't going to start at all, but persistence paid off in the end.
I'd like a theory in place before I take it in to the dealer because I know they're new to Royal Enfields, and probably haven't come across this - yet.
4200 miles otherwise trouble-free.
Yes, more likely to be the auto-decompressor. That's a sound that a decompressor would make.
The sprag is simply one of the gears in the electric starter system, which is a one-way gear like a ratchet, which the starter turns when starting.
It has parts inside the sprag gear, called a sprag clutch, and this is what makes it work in one direction only.
If something happens to make the bike kick back, it can break the sprag clutch mechanism, which was a common occurrence on the older models which had electric starters.
It is my view that the auto-decompressor also helps to protect the sprag clutch from breakage, by letting the engine begin to spin-up and get some forward momentum, before the auto-decompressor releases at the specified rpm point, and then the engine starts.
By removing the auto-decompressor, you do raise the risk of damage to the sprag clutch by a kickback. It's simply a matter of solving one problem, but leaving yourself open to another problem occurring later.
The ideal circumstance would be to fix the auto-decompressor so that it works properly, and the system will function as intended, and the sprag clutch will be more protected from damage.