Topic: CB350F throttle adjustment screw below hand grip

[birdmannn101]

Has anyone used the throttle adjustment screw on the handle of a CB350F and what exactly is it supposed to do?  I have tried to tighten this screw to see if it would hold the throttle open and it doesn't work.  That could be expected since most parts on this bike are from another bike that I used during restoration.  Someone told me this screw could be used like a throttle lock.

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[HondanutRider]

Yes, that part activates the throttle lock mechanism.  It is supposed to put pressure on the throttle tube so that the return tension of the carb springs will be compensated, allowing for less return action all the way to holding the throttle on, depending on how much tension is dialed-in on the knob/screw.  This screw bears down on other parts to provide the friction to resist the carb spring tension - part #8 in your diagram I believe.  You need to check and see if that part is there.

For safety reasons (e.g. preventing locked-up wide-open throttle) I don't believe this adjustment screw was included on all market areas.  It is however, installed on my 1974 350F that was sold here in Canada.

[birdmannn101]

Part #8 the "adjuster" might be missing.  I am trying to picture how this is installed in the switch mechanism.  That is probably the reason this friction doesn't work when I tighten the screw.

Thank you very much for getting back to me on this.

[HondanutRider]

I believe part #8 acts like a brake shoe and is pressed down by the screw onto a part of the throttle tube.  It probably is spring steel and is a "folded" piece with one side on the screw (with a hole in it that the end of the screw rests) and the other riding on the tube.  I haven't taken my 350F apart to look at it, but the parts diagram seems to look like what I've seen installed on other models of Hondas in my collection.  These earlier models don't have an adjuster knob like the 350F, but rather a small screw with a lock nut.

[Grim]

I recently replaced the throttle tube and cables on my 73 CB350F and before even re-installing the throttle adjustment screw the throttle grip is very difficult to open or close (it will stay in whatever position I leave it in, does not return at all). It was free moving before replacing the tube and cables (had to redo handlbars due to it being knocked over while parked). I first thought that the new tube was rubbing inside the switch housing, but it doesn't look like the rubbing is accounting for the entire stiffness. What part of the switch housing would the throttle adjustment screw make contact with the tube? If the tube and cables move freely when not in the housing is there anything else that could be the issue?

Thanks!