Your point is well taken, though, Damocles. I shall modify the title a bit...
Tom Schmitz, I appreciate the thread title revision, resulting in more accurate and precise prose!
And, I've no problem with anyone's lexicon whose nomenclature of "doohickey" includes idler shaft lever and spring only.
If the term, "doohickey," is an umbrella for the entire balancer chain tensioning system, other components may be involved besides the idler shaft lever and spring alone. For example, a dozen separate parts in this fiche comprise the balancer chain tensioning mechanism:
I consider the doohickey (idler shaft lever) and the tensioner spring as two separate parts. These components are identified and sold separately by Kawasaki, and marketed individually by Eagle Mike and other aftermarket vendors; that is, no "doohickey assembly" consisting of lever and spring exists, AFAIK
. The doohickey-and-spring are not distributed as a "set," either may be replaced independently of the other.
Parts in the fiche: cap/bolt, idler lever/O ring, 7mm/lever, idler shaft (doohickey)
/circlip-type-c 20mm/llever/washer, 20.3 x 36 x 1.5/spring
Generation 1 doohickeys (idler shaft levers) sometimes failed, disintegrated, broke, "grenaded." This malfunction sometimes resulted in catastrophic engine damage; cam chain de-sprocketing, bent valves, burst piston crowns, etc. Don't know of any Generation 2 OEM doohickeys with similar failure mode and consequent engine damage.
Spring issues surface, but as in the videoed example, without the trauma and carnage of the Generation 1 doohickey (idler shaft lever) failures.