What exactly failed? No humor here but what caused the failure? The spring broke? Sprink got weak? Did the mounting point of the spring fail? Did it just come off? I cant see the video clear enough to tell. Work locks u-tube so I am viewing on a cell phone.....
Why replace the lever if nothing is wrong with it? Can only the spring be replaced and whats that procedure? I have been told to use the torsion spring you have to grind some material on the lever?
I'll reiterate what KLR4ever and SkiBumBrian have said as an intro to personal comment.
There has never been a documented failure of a Balancer Adjustment Lever on a Gen2 bike ever ever ever in the whole wide world. It's all better now.
The spring is now the weak point and is well known for going slack quickly and some have reported them as slack before the first oil change. I have no cite for that, but it must be true because I read it on the Internet.
This bike is new to me at 16,000 miles and still has an extended warranty that was transferred to me and is good for two more years. I could have let the whole thing go and relied on the warranty to repair anything that went wrong with it.
In my tool box I have several of Mike's extension springs. I could have gone in there and left the stock lever in place and merely put a new spring in. The engineer in me agrees with Brian, though. The stock lever doesn't fit that well on the shaft, which allows the shaft to oscillate, putting the spring through many cycles. Engineers don't like the things they rely on to oscillate or vibrate un-necessarily as that leads to component failure. Engineers don't like that even when there is not a single case of documented failure. The potential is scary enough, for engineers are worry warts with furrowed brows who curse the accountants that keep them from making everything totally bitchin'.
What I want in a balancer chain tensioner system is one that I don't ever have to think about again. Seriously - I don't want to take that damn rotor off ever again. I'm old; my shoulders have arthritis and I can barely get the bolt back up to proper torque. I'd much rather be doing something else, even if it is equally stupid. Alas, with the KLR that is not possible because the basic design is a Rube Goldberg affair that no self-respecting engineer would think of except in some sort of acid-induced nightmarish flashback. Cue the Jefferson Airplane tracks...
The closest we can come to set and forget is Mike's lever and his torsion spring.
Sure, you can get out your Dremel tool and put a groove in it and use the torsion spring with it. It's your time, your part, your bike. If you have modest talent with tools the job will turn out fine, though the lever will still fit a bit sloppy on the shaft. If that doesn't bother you, have at it.
You can just put in a new spring and keep an eye on it and go back in at some point in the future should that one, too, become slack. Mike gives you a couple different lengths.
The way I figure it, though, is that once you're far enough in to the engine to remove the stock spring, you have already invested a couple hours of time, bought a pair of gaskets, a new rotor bolt, and have gone to the trouble to get the tools required. Why in the Wide Wide World of Sports wouldn't you just take the easy way out and install a spring and lever that are designed to work together and have a pretty fair track record for an additional $40?
Hey! Who moved my horse while I was talkin'? Here I am, beating on a warm soggy spot where a dead horse once lay....