throttle not returning

[El__burro]

As per subject line, my throttle is not returning freely.
The twist grip stays in the open position unless i twist it back.
Not sure if the problem is at the handlebar or carb mounting.
What's the first step you recommend.

Thanks
el__burro

[K2-K6]

If you take too much slack out of the pull throttle cable then you get a conflict with the return one and the resulting friction makes operation really stiff.

Big coil spring on main lift spindle on carb assembly can wear through at one end and disconnect.

As a base line setup, if you detach the return cable at the carbs then see how it operates it will tell you if you need to go further..... Still too stiff? Also take off the pull cable then the main lift spindle should move easily with your fingers and snap shut easily,  if not you are probably looking at the lubrication and cleanliness of the bearings supporting that shaft.

[Bryanj]

Cable routing makes a big difference Also DO NOT lubricate the internals of the original cables as the inner is rubber coated and the outer is nylon lined and oil tends to make them swell into each other and bind

[Chris400F]

Are you still using the Doherty twist grip with single cable or did you change it?

[Aly-b]

When I bought my bike, (cb550) it was fitted with new aftermarket cables and routed wrongly which made the action very stiff.
After removing the cables,oiling them and rerouting as per the manual it made a world of difference.
Now have a smooth throttle which snaps back easily.
Best of luck with yours.

[El__burro]

The throttle comes from a VTR1000F and it fits nicely.
I am not sure about the routing.. (check the img attached).

Thanks
el__burro

[neat street]

Also check the routing from the carbs, should go over the fuel tank brackets I believe? I had the same issue with mine when steering turned right. re-routed cable over the top of the fuel tank bracket, and all fine.

[El__burro]

Removed the tank and disconnected the return cable (bottom one).
It works fine.
Then I need to reattach the cable again and the problem is back.
any ideas?

el__burro

[K2-K6]

I don't know what adjustment you've got on your cables,  the standard ones usually have no adjustment for the return cable so no options there.

The pull cable has more scope so put all the slack you can get in that one and it should get rid of the conflict between the two. I know it sounds kinda back to front but it's how they are set up, you can then adjust the pull one a little if you need to but if you do, then check as you are doing it by turning the steering from full left to full right while twisting and releasing the throttle to make sure it doesn't bind again.

The Honda manual stipulates just how much slack the twist grip should have in it to avoid the cables binding but people tend to adjust them tight and think the throttle will somehow open further.

[Greebo]

Removed the tank and disconnected the return cable (bottom one).
It works fine.
Then I need to reattach the cable again and the problem is back.
any ideas?

el__burro

When you put the tank back on sounds like you maybe trapping/bending the cables in an awkward position

[Chris400F]

Does the inner of the return cable move freely, particularly when the cable is in place?
Can't see what angle it is coming out of the twistgrip from the photo as the cables are underneath.

[El__burro]

Here are some pictures of the extremity of the cables.
When I unhook the lower (return) cable from the carb link it does fine.
el__burro

[hairygit]

Looks like the opening cable is over tight, where the cable attaches to the carbs there should be a locknut either side of the bracket, in the picture you have both at the end of the cable bracket, try it with one nut either side.

[tom400f]

Might be too obvious but both of the cables look stressed where the flexible leaves the twist grip, they take an unnatural downward turn. Perhaps route them above that brake union? Not sure what the correct routing should be and how customised your bike is.

[K2-K6]

A question,  has it always done this, difficult to turn, since you had it going? Or has it changed?

When you disconnect the carb end of the return cable it will still be moving that cable but the action is ok. So it's not coming from the internal cable being stiff.

With both cables connected, is there any rotational slack at the twist grip at all and if so how much?