Throttle return spring....to strong

[K2-K6]

Putting aside some of the proliferal observations for a moment, the Honda system used on these bikes is not directly comparable to other manufacturers designs unless the whole system is the same.

The design of this setup is that the pull cable opens the throttles and the spring closes them, not the second cable. The second cable just "floats " and remains as a contingency in the event of a spring failure,  or enough friction that the spring could not overcome that friction to close the throttle.
Other systems commonly use more than one spring within their design,  which gives those systems a contingency to close the throttles in the even of one spring failing. This does not exist in the Honda system,  the second cable IS the only safeguard. It may appear over engineered or in excess of what seems to be needed but it is their solution as originally designed.
Like any good contingency measure,  it can sit there for years with no impact until it may be used. It causes not real problems to have it there and IF you needed it,  you'd most likely welcome it's correct working.

Sure it may or may not be spotted ( if not fitted) by a insurance assessor, that's neither here nor there in just a general insurance claim. But if your bike was involved in an accident in which you could not stop it because the throttle was open, then that would by its nature involve more scrutiny of the relevant systems and the maintenance of them.

[mike the bike]

And if the kill switch wasn't working.   That's a lot of ifs.

[K2-K6]

That's what realistic contingency deals with,  all the ifs lining up, to stop people wondering why there was an accident that could have been mitigated with a competent plan to split the chain of events.

[Seabeowner]

Don't forget that early models also had "cruise control"!!!? That screw beneath the throttle that could be used to increase friction/or actually lock the throttle open. The close cable would always overcome this, but the spring may not. I'm sure any who still have this on their bikes it's only for originality.
Also this is from the 500 owners manual:

[matthewmosse]

I would really think its best to just be sure to tell insurance if you run with this alteration. Covers you in the event of a misshap. Just be sure you keep a close eye on the cable condition and that the kill switch works. Myself, I'd stick to stock as I've found it ok, took me a while to recall that I found the throttle heavy at first, but adapted my technique and that resolved my issue.

[Bryanj]

Never mind insurance or anything else if you have just a pull cable with Honda twistgrip there is excess free play that you simply can not adjust out, just prepping 500 for sale and was going to fit new cables but found i hadn't fitted the return cable correctly when the carbs were off fot fuel pipes!

[K2-K6]

It looks as if it's considered as just another cable when people take a decision to delete it and have no real idea of its role within the overall design.

Every bike and car I've worked on has some secondary method of closing the throttle in a potential failure situation ( or in the case of a slide carb, a captive compression spring), this is just Honda's way of doing it and adding a competent engineering solution to avoid the throttle running out of control.

The notifying insurance angle is interesting but not tested unless an accident or claim is considered. It goes further than that though, construction and use laws are absolute and not subject to your own decisions. They examine your actions against wording like "failure to maintain a vehicle and it's accessories " under which you'd be able to persuasively argue that your removal of a manufacturer fitted safety design was reasonable, I assume.

Also,  you have no contract with a third parties insurers whether you damaged them or they've damaged you. And then you get to the claims solicitor "specialists" that may be brought in by another party.

Really, it's easier just to run with it,  and it works.

[AshimotoK0]

What amazes me is people pay an ABSOLUTE fortune for sandcast '28' carb tops and associated cables etc. These were replaced early on as an aggressive  recall to prevent  a potentially lethal scenario. It's a bit like someone searching for the original Toyota mats that caused all of that hoo ha a few years back.

What do you (I) do about the CB500K0 early gearbox?  ..  there was a Class Action Lawsuit against Honda in the States in relation to it.

My 2p on the throttle cable .. listen to Rex Harrison and fit the 'Push-me-pull-you' arrangement ... You know it makes sense !