Topic: Need help with a stiff throttle

[Really?]

Previously it was a sticky throttle.  It felt like there were bumps in it when twisting the throttle.  I found the sliders were sticky (my finger stuck to them) and had a lot of sticky build-up.  I cleaned out the carbs.  Before putting the rack back together, one slider dropped on its own weight and the other dropped with a slight tap.   The part that moves all the sliders moved freely.  I did notice they may have snugged up a bit when the rack was put together with the carbs but they still dropped on their own.  So, the sticky throttle is fixed - I hope.

Now I have a stiff throttle.  Basically, it it kind of tight to turn either way.  It will close on its own but it is very slow.  I put the second spring back on the the PO had put there (it helped a little, not much). I lubed the cables and the plastic throttle piece on the bar.  The cables slide very very easy while twisting the throttle but not connected to the carb rack.  I sprayed the rack linkage (that lifts and lowers the sliders) with SeaFoam's Creep Lube stuff.  It did feel like there was pretty good tension on the return spring mounted to the linkage and between the #2 & #3 carbs but I did not do a tension test of any kind, just with my finger pushing against it and when putting it back together,

I have tried re-routing the cables around the left side of the frame but it seemed to get tighter, so I put them back.  They are currently routed around the tach cable (big bend), straight back at a downward angle, under the coils and then above the frame cross-member.

What can I do to loosen up the twist of the throttle?

[strangedaze39]

The less bends the cable has the better, you want it completely clean from inside the right control down to the carbs. If you don't have a push and pull 2 cable system, but do have a 2 cable push and pull throttle sleeve which is common. Make sure your cable is on the pull hole on the sleeve. Make sure everything is connect properly at the carbs, play with the throttle by hand on the carburetor and see how it feels.

Thats all I can think of now, hopefully one of those will hit. BTW mine is set-up as good as it's going to get and it's still one of the tightest throttles I've used 

[Spanner 1]

Any chance you have bar-end mirrors...the expanding cam caused this prob. on my friends bike.............

[Really?]

The less bends the cable has the better, you want it completely clean from inside the right control down to the carbs. If you don't have a push and pull 2 cable system, but do have a 2 cable push and pull throttle sleeve which is common. Make sure your cable is on the pull hole on the sleeve. Make sure everything is connect properly at the carbs, play with the throttle by hand on the carburetor and see how it feels.

Thats all I can think of now, hopefully one of those will hit. BTW mine is set-up as good as it's going to get and it's still one of the tightest throttles I've used 

I have big bends from the controller to between the headlight bucket and tach cable.  The cable are long now since the change to superbike bars.  Now in kind of bends down below the coils and the above the cross-brace in the frame right after it.  Is this the correct routing?  That is the way it was when I took it apart.

It has what I believe to be stock for the K5 (the controller). 

I do not know how to decipher what you said here - "If you don't have a push and pull 2 cable system, but do have a 2 cable push and pull throttle sleeve which is common. Make sure your cable is on the pull hole on the sleeve."

I will mess around with it a bit more.  It feels somewhat unsafe as it is.  I can live with it and control it as it is, It is a bit rough on her as this is her first bike and she rode it the first time on Sunday.

Any chance you have bar-end mirrors...the expanding cam caused this prob. on my friends bike.............

I can check this out, it is quick to pull off.  Yes, they are bar end mirrors - the cheapies.  So, is it possible for the expanding cam to oblong the handlebar enough to make it tight for the throttle sleeve?  I would have figured the bar to be fairly strong.  I do not believe the grip is on it that hard but I will check that again.

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I was kind of wondering if maybe I did not get the rack on the boots right?  All four boots look to be up again the carb rack.  Would the rubber at the top of the slides that connect to bar that lifts them cause something like this?  I lubed them too.  Do I need to lube the sliders in some way?  I would have thought that the fuel running through would help keep it lubed.

I will keep messing with it and do the suggestions above.  Please feel free to offer more suggestions y'all.

[schwebel]

I had a similar problem and i ended up being the cable. I tried everything in the world because I thought since the cable moved easy detached from the carbs it couldn't be the problem. But when you detach it, it is not under any tension to truely test it. I bought a new cable and it is like brand new. I also swaped to superbike bars, and the cables are little longer but hasn't caused a problem.

[Really?]

I had a similar problem and i ended up being the cable. I tried everything in the world because I thought since the cable moved easy detached from the carbs it couldn't be the problem. But when you detach it, it is not under any tension to truely test it. I bought a new cable and it is like brand new. I also swaped to superbike bars, and the cables are little longer but hasn't caused a problem.

I'll add this to the list.  One cable is darn near new and the other looks to be original.  I'll get that other one ordered today.


I'll probably pop the caps off the sliders and spray that Seafoam Creep in there to see if that helps.

Edit: I have read in a post about chafing in the cable sleeve.  I can see the possiblity of when the cable is under load that it could drag along the chafe and slowing things up.

[Duke McDukiedook]

New cables, lube the moving parts of the carb assembly/rack with liquid graphite.
Try to make sure your bends are larger than a tennis ball.
See how that does it.

[tlbranth]

My bike has only a pull cable, but I think if I were trying to diagnose this problem I'd first separate the cables from the lifting assembly and then isolate the problem to the assembly or the cables. Too much guessing right now.

[Bodi]

There's a cable routing diagram in the Honda shop manual. I had pretty major clutch pull trouble until I routed the cable the way Honda planned it... much better afterwards.
The twistgrip assembly should move quite freely with no cables when fully assembled, it's possible for the part where the cable attaches to get bent out of shape and drag on the metal housing.
You need a bit of slack in the cables or it gets super stiff. You should be able to see the cables slacken a bit around the carb wheel when you rock the throttle back and forth.
Having cables the wrong length usually causes trouble too. It sounds like that may be the case with yours but if the loops are large it shouldn't be as bad as you describe.
Cables can be a total mystery though. I had a new clutch cable that seemed a bit tight, so I lubed it with motor oil. This attacked the lining and made it swell up, making it immovable and sending it to the trash. Others need to be oiled or are horribly stiff.
Good luck with this one!

[strangedaze39]

I have big bends from the controller to between the headlight bucket and tach cable.  The cable are long now since the change to superbike bars.  Now in kind of bends down below the coils and the above the cross-brace in the frame right after it.  Is this the correct routing?  That is the way it was when I took it apart.

It has what I believe to be stock for the K5 (the controller). 

I do not know how to decipher what you said here - "If you don't have a push and pull 2 cable system, but do have a 2 cable push and pull throttle sleeve which is common. Make sure your cable is on the pull hole on the sleeve."

I will mess around with it a bit more.  It feels somewhat unsafe as it is.  I can live with it and control it as it is, It is a bit rough on her as this is her first bike and she rode it the first time on Sunday.

 Hey TipperT,

 I have superbike style bars also on my bike, so I know what you mean by the cables being a bit to long. Someday I need to get some custom cut cables, you'd be surprised how much having a extra bend in the cable or just a sharp bend, can tighten things up. It sounds like you have the cable routed correctly. You actually don't need to route it correctly. My CB350F has 2 brackets for my cable to slide through but I only use one. Ideally you want a single bend in the cable thats a mellow sideways U shape with the bottom of the U sticking forward.

About the push pull system and throttle sleeve. Do you have a push pull throttle? (Meaning do you have 2 throttle cables coming from you're controller) If you don't open your controller up and take a look at your plastic throttle sleeve. It will either have one or two "sockets/holes" for the throttle end bolt to slip into and hold in place. Here's what mine looks like with a single throttle cable on a push/pull (2 cable) sleeve.
Me holding it so you can see what I mean:


How mine sits when enclosed:


Hope that helps Tipper, I wish my throttle was just a bit easier to deal with also. No joke the guy I bought the bike from has a huge collection of old hondas (dreams supers etc.) and he said he just can't ride them anymore because the throttles and clutches are to tight. Although, I thought to myself. Come on man you not much over 50 work those hands out 

[MCRider]

I had a similar problem and i ended up being the cable. I tried everything in the world because I thought since the cable moved easy detached from the carbs it couldn't be the problem. But when you detach it, it is not under any tension to truely test it. I bought a new cable and it is like brand new. I also swaped to superbike bars, and the cables are little longer but hasn't caused a problem.

Yes it can be frayed internally which will only show symptom when hooked up. Cable is the biggest part of the whole system, gotta be suspect.

The bar end mirrors won't elongate the handlebar, but they might rub on the twist grip as it had to be cut to allow the mirror in and it may not be cut enough.

My money's on the cable.

OCICBW

[ZanVooden]

I had a problem similar to this not long ago. Found out that the push and the pull cable were fighting each other, the push cable was too tight and the pull was too loose.

Playing with the adjustments on the cables is what worked, and making sure the cables at the controls were in the correct position. I started by hooking up the pull cable to the carbs, then the controls, then hooking the pull cable to the carbs.

[Really?]

Still haven't gotten to this yet but will.  Ordered a Motion Pro push cable since that one looked like the original.  The pull cable looks perty darn new.  I ordered a new throttle sleeve too since it looks original.  I will update this thread.

[scottgarland]

Try removing cables from carb assemblys to see if carbs are working correctly then check cable operation. Good luck.

[Really?]

Now that I think about it, the push cable is not very strong where it connects to throttle sleeve.  I wonder if, when under load, it starts to curl in the housing causing drag.  Who knows, lol.

[MCRider]

Now that I think about it, the push cable is not very strong where it connects to throttle sleeve.  I wonder if, when under load, it starts to curl in the housing causing drag.  Who knows, lol.

The B cable (I hate calling it a push cable, cables don't push, though I know this is common usage) is just along for the ride. Remove it and see how the throttle feels. Replace it if necessary. It could be interfering if grungy or damaged inside.

The B cable should be mildly slack and once properly adjusted will not interfere with anything. It just glides, maintaining that amount of slack, and it only operates if the carb slides are dragging, return spring has failed, etc. and they won't shut.

[IHWillys]

Get it working nicely with just the opening cable first.  Then you'll know what it should feel like after the closing cable is in place(ie, should feel no different).  Also get any bar-end weights/mirrors off and don't install until the throttle is working correctly.

I had slightly "sticky" throttle action after getting the rack and cable free and lubed.  I found it to be the cable end(ferrule, IIRC) in the twist grip.  As the throttle is twisted, the ferrule twists in the plastic socket.  It was hanging up and "ratcheting". This is a metal on plastic point so I used dry graphite lube on it and the issue went away.  Throttle is now smooth and snaps back to closed when released.  I am not running a closing cable at this time.

Ken

[MCRider]

Get it working nicely with just the opening cable first.  Then you'll know what it should feel like after the closing cable is in place(ie, should feel no different).  Also get any bar-end weights/mirrors off and don't install until the throttle is working correctly.

I had slightly "sticky" throttle action after getting the rack and cable free and lubed.  I found it to be the cable end(ferrule, IIRC) in the twist grip.  As the throttle is twisted, the ferrule twists in the plastic socket.  It was hanging up and "ratcheting". This is a metal on plastic point so I used dry graphite lube on it and the issue went away.  Throttle is now smooth and snaps back to closed when released.  I am not running a closing cable at this time.

Ken

I'm perfectly OK with not running one, but, geez, admitting it is like jumping headfirst into an oil thread!   

[Really?]

That's funny.  I had no idea. 

I was keeping it there becuase that is the way it was.  But a kewl idea, none the less.

[SOHC4ever]

Get it working nicely with just the opening cable first.  Then you'll know what it should feel like after the closing cable is in place(ie, should feel no different).

So: my throttle should feel the same with the "push" cable removed as it does with it on? I broke mine a while ago, and experienced a much looser throttle w/o it. I wasn't able to "close" the throttle, though, which is always what I thought it was for. (carbs are clean, return spring is present).

Am I relying too much on my push cable? It's a new motion pro cable, and both cables are properly lubed & routed.

[MCRider]

Get it working nicely with just the opening cable first.  Then you'll know what it should feel like after the closing cable is in place(ie, should feel no different).

So: my throttle should feel the same with the "push" cable removed as it does with it on? I broke mine a while ago, and experienced a much looser throttle w/o it. I wasn't able to "close" the throttle, though, which is always what I thought it was for. (carbs are clean, return spring is present).

Am I relying too much on my push cable? It's a new motion pro cable, and both cables are properly lubed & routed.

I've never heard of a B cable breaking as it does nothing. It is there solely as a backup to the return spring. It must have been a wreck.

Without it, the A cable and the return spring alone should do the job completely and fluidly, with no hesitation, it should snap fully closed when released. If it doesn't you've got work to do. This is a safety issue.

[SOHC4ever]

Get it working nicely with just the opening cable first.  Then you'll know what it should feel like after the closing cable is in place(ie, should feel no different).

So: my throttle should feel the same with the "push" cable removed as it does with it on? I broke mine a while ago, and experienced a much looser throttle w/o it. I wasn't able to "close" the throttle, though, which is always what I thought it was for. (carbs are clean, return spring is present).

Am I relying too much on my push cable? It's a new motion pro cable, and both cables are properly lubed & routed.

I've never heard of a B cable breaking as it does nothing. It is there solely as a backup to the return spring. It must have been a wreck.

Without it, the A cable and the return spring alone should do the job completely and fluidly, with no hesitation, it should snap fully closed when released. If it doesn't you've got work to do. This is a safety issue.

Very well. Where do you propose I start? As I mentioned, cables are routed properly and the return spring is present and... springy.

[MCRider]

"Very well. Where do you propose I start? As I mentioned, cables are routed properly and the return spring is present and... springy."

Hmmm,

remove the B cable. IT goes back after the throttle is fixed. Probably overkill, but i'd take it completely off so there's no way it can interfere.

Remove the A cable from the carb. , reach in and operate the carbs by hand, lift the bellcrank and release. The carbs should snap down. Is there a problem with idle? If your carbs are synched improperly, they may snap closed but the slides really aren't down to idle position and you're using the B cable to draw them closed. Just a thought.

Hold on to the carb end of the A cable and turn the twist grip. If there is a problem there it may be telegraphed into your fingers and you could feel it. Like a crunchiness or a glitch.

Just gotta fish around.

[SOHC4ever]

Is there a problem with idle? If your carbs are synched improperly, they may snap closed but the slides really aren't down to idle position and you're using the B cable to draw them closed. Just a thought.

Indeed, the carbs won't close w/o me closing them with the throttle cable. I just thought that was how it was supposed to go.

Carbs were synced w/ a morgan carbtune and are all within 2cm Hg of each other. Does that in and of itself = properly sync'd carbs, or have I missed something?
I fiddle with the idle as the bike warms up, but I understand that such fiddling is standard on this type of machine. I will take your advice, remove the B throttle and fiddle with all of the connections. Thanks.

[MCRider]

Is there a problem with idle? If your carbs are synched improperly, they may snap closed but the slides really aren't down to idle position and you're using the B cable to draw them closed. Just a thought.

Indeed, the carbs won't close w/o me closing them with the throttle cable. I just thought that was how it was supposed to go.

Carbs were synced w/ a morgan carbtune and are all within 2cm Hg of each other. Does that in and of itself = properly sync'd carbs, or have I missed something?
I fiddle with the idle as the bike warms up, but I understand that such fiddling is standard on this type of machine. I will take your advice, remove the B throttle and fiddle with all of the connections. Thanks.

Its been a while since I synched a set, but if memory serves it is possible to pull a slide up with the adjuster nut too far, thus not allowing it to settle down into full down position. I may be way off here, as memory can be.

Yes "idle fiddling" was the subject of a very long and convoluted thread here a while back, very humorous.

But the fact remains, throttle control including returning to idle should all be accomplished by the A cable pulling up, and the return spring closing. B is just along for the ride... unless its needed due to a spring failure or some carb hang-up that the spring can't overcome.