Topic: fantom neutral overrev? 79 CB650

[cosmosschwarz]

So it happened.  Got a false neutral in between shifts today, and somehow laid back on it and ran it to 10-11k before I realized and let off.   Suprisingly it still ran, made it home, but the valvetrain sure is noisy now.  Gonna let it cool off and go take a look.  Any ideas?  I would assume since its still running at all that I didn't bang a valve, but could it have caused other damage to the springs, etc. and still be running?  Guess I'll check the cam chain tension first, see if that helps.   Something tells me I'm going to have to re-adjust the valves I just adjusted last week 

[Gordon]

Valve clearance lock screws sometimes like to loosen or completely remove themselves when that happens, allowing the adjusters to readjust themselves.

[dave500]

yeow i hate that!it should be ok,just recheck the tappets and chain tension,if something was gonna go bad it would have by now,when did it last have an oil change?if its near due it might quieten it aswell.

[phil71]

wait, wouldn't the big question be: "how do we prevent phantom neutrals?". Do backcut gears address that, or are the dogs to blame?

[dave500]

backcutting is backcutting the dog engagements.

[Hush]

My 79 650 does that quite a bit, most embarressing when tooling around town and on accelleration suddenly you are not going anywhere but the bike sure is revving hard!
I always blame myself for not fully engaging the gears and sometimes resting my boot toe on the direction I will be moving the lever next.

[cosmosschwarz]

well, all signs point to everything still being in one piece.  Adjusted the cam chain tension and the majority of the noise is now gone.  Took it out for a good ride last night and it seems ok.  Hopefully the weather holds up so i can ride into work tomorrow and check the valve adjustment at lunch(feeler gauges are at work).  Wondering now about an aftermarket ignition that would allow a rev limiter to prevent such happenings.

[Hush]

Nah don't try to improve on perfection!