Topic: 1975 CB550 Throttle Adjustment Frustration - NEW PICTURES ADDED

[quidger]

I took off the carburetors to put in new needle valve and o-rings. I did not touch the linkage, simply took the bowls off, adjusted the floats and put the new o-rings and needle valve set in.
The throttle cable is brand new - probably 200 miles on it since the bike was re-assembled a few months ago.
The throttle was working perfectly - snapped back strongly.
I put the carbs back on and hooked up  the throttle cable and now I cannot get it adjusted to snap back.

Only the pull cable is adjusted -Am I  Correct? The push part of the cable has no adjuster - it just snugs down - Am I Correct? I adjusted the pull adjuster as far as it would go in both directions jsut to see what effect it might have. And in both positions there was never any tension on the cable. With both ends of the cable unhooked the cable moves freely. So the cable is fine.
I posted a couple of pics in hopes that someone can see something that I have done incorrectly.

Any help would be appreciated.

I didn't do any adjusting of the small adjuster at the grip as I think that should only be used for micro adjustment - and I need more than micro adjustment at this point.

Thanks for your input.

[Eddie]

first , is your throttle all the way closed ? you should be able to confirm by looking at the sliders to see if they are almost closed.  The "pin" in the picture that looks like it's off center on the bolt needs to be rotated to stop the throttle from being forced past its closed position. Perhaps the pin is loose?  Is the main spring still connected...it's between the #2 and #3 carb.

[quidger]

first , is your throttle all the way closed ? you should be able to confirm by looking at the sliders to see if they are almost closed.  The "pin" in the picture that looks like it's off center on the bolt needs to be rotated to stop the throttle from being forced past its closed position. Perhaps the pin is loose?  Is the main spring still connected...it's between the #2 and #3 carb.

I'm sure that the throttle is all the way closed and the sliders have just a bit of daylight coming through (bench synced them). Main spring is still connected. I unhooked the cable ends from the adjustment holders and snapped the linkage physically to make sure that the spring had not come undone.

This is a real mystery to me. All I basically did was take the carbs off and re-install them without touching anything but the float bowls.

[quidger]

A week later and several hours later I'm still trying to figure out the issue with the throttle cable.

1) When I unhook the throttle cables from and twist the throttle grip, the cable move freely and smoothly back and forth. So it is safe to assume that they are not kinked or bound up.
2) But when I manually pull the end of the of both cables there seems to be resistance and they don't move as smoothly and freely as when I use the twist grip.  Is this normal?
3) I disassembled the twist grip throttle assembly to see if the cable ends were hung up or out of the grooves that they fit into. Everything checked out fine there.

Still looking for suggestions so if anyone wants to chime in I would appreciate it.

Thanks

[Tews19]

They wont snap back like a new bike. I am not sure if that is what you are trying to gain. I have play of about 1/8" in mine that I can move with no push or pull response. You can adjust the bolts at the end of the cable but also on top of the cable as well. It is on the bottom but when the cable goes into the sleeve.

[bjatwood]

Take a pic of the adjustment's by the throttle grip so we can see what that looks like. Sometimes new cable are much tighter (less stretched) than the one's we take off and the adjustment will be way different.

[Duanob]

Did you check the return spring on the linkage?

Cruddy cables?

You should have 1/8" of play at the throttle before the pull cable actuates the carb slides.

[quidger]

Linkage spring is strong on the carburetor rack and snap backwhen the cables are not hooked up. When I hook up the throttle cables there is not snap back - it just slowly and barely returns to the closed throttle position.  The cables are new.

Cables slide freely and smoothly when I twist the throttle grip and the cables are not assembled to the carburetors.

[Duanob]

Throttle grip gummed up?

Throttle control screws too tight. I think 1975 had the throttle set screw on the bottom of the throttle control. It's a spring loaded set screw.

Kink in the cable somewhere?

[Frostyboy]

I know you said it was okay before, but are the cables routed correctly? Just guessing. Maybe try turning the bars to see if it improves.

[TwoTired]

1) When I unhook the throttle cables from and twist the throttle grip, the cable move freely and smoothly back and forth. So it is safe to assume that they are not kinked or bound up.

No.  Cables with sharp bends in them will move freely unless under some tension.  The tension moves the cable against the sidewall in the bend and that introduces sliding resistance.

2) But when I manually pull the end of the of both cables there seems to be resistance and they don't move as smoothly and freely as when I use the twist grip.  Is this normal?

See above.  If you make the cables straight, do you still get resistance under tension?  Essentially, the more bends they have or the sharper the bend radius, the more resistance they will have when under tension.

Are you using stock bars and stock cable routing?

What brand of cables are they, and have they been lubed?

[dave500]

make the pull cable too slack at the carbs,then bit by bit adjust the slack out of it,then finish the adjustment at the twist grip end,the two cables can fight each other.

[Lars]

If the cable routing is correct, and none of the lifter arms have been pushed out of position, it is just poor adjustments where they connect to the carbs. Probably too thight on the lower one. Disconnect the the lower cable, does it work nice now?

[quidger]

1) When I unhook the throttle cables from and twist the throttle grip, the cable move freely and smoothly back and forth. So it is safe to assume that they are not kinked or bound up.

No.  Cables with sharp bends in them will move freely unless under some tension.  The tension moves the cable against the sidewall in the bend and that introduces sliding resistance.
After fiddling with the cables for quite some time now I decided to add a couple of more pictures to show the routing of the cables.
Please let me know if you can tell from looking at the photos if my routing looks incorrect.
It seems to me that this is the logical culprit to my issue but the diagram that was posted does not make it clear if I have routed incorreclty or not.

2) But when I manually pull the end of the of both cables there seems to be resistance and they don't move as smoothly and freely as when I use the twist grip.  Is this normal?

See above.  If you make the cables straight, do you still get resistance under tension?  Essentially, the more bends they have or the sharper the bend radius, the more resistance they will have when under tension.

Are you using stock bars and stock cable routing?
New bars that are a bit lower in stance than the old OEM bars that I took off.

What brand of cables are they, and have they been lubed?
Brand new OEM Honda cables. Not lubed. In use for a few hundred miles since installation.










Thanks to all for the help and input.

[dave500]

your on the wrong side of the frame,mine run on the right side of the head stem and over the right hand forward tank mount.

[TwoTired]

Your routing looks ok with the bars positioned to the right.
You should do a test to see if the throttle friction changes with the position of the bars turn left right and straight ahead.

I have to disagree with Dave about routing on the right side of frame.  Routing the cable on the same side of the throttle control will exacerbate the cable bending radius issue, as it shortens the distance between throttle and carbs.  With higher bars, right side routing could be helpful, though.

Lower bars means that the cables would be shorter than stock.  And, to behave as stock, less reach needed.  The excess length has to wad up somewhere and that usually means a smaller bend radius will occur.

It could be that you just need to lube them, using a dry lubricant.  I would not recomend a "wet" lube as it may soften the inner nylon or teflon friction core.  I have used a product called Dri slide.  While it installs wet, it doesn't stay that way for long.
Remove the cables and hang them vertically, over a catch pan of some sort.  Poke a hole in the corner of a small baggie and insert the top cable end into it with a rubber band sealing to the cable jacket.   The baggie makes a funnel so the Dri slide liquid can channel inside the cable jacket.  When some of the fluid comes out the bottom work the cable and twist the inner component to more evenly distribute the lube inside the jacket.  Rubber gloves are recommended.

Let it sit overnight to drain and dry out.  The carrier solvent in the lube will evaporate leaving the dry lube in place.

Clean off the outside of the cables and reinstall.  You might even try to the point the throttle mount bends forward so one large radius is formed from that point to the frame spine left side.

I'd like to hear of the progress you make.

Cheers,

[Tews19]

Your routing looks ok with the bars positioned to the right.
You should do a test to see if the throttle friction changes with the position of the bars turn left right and straight ahead.

I have to disagree with Dave about routing on the right side of frame.  Routing the cable on the same side of the throttle control will exacerbate the cable bending radius issue, as it shortens the distance between throttle and carbs.  With higher bars, right side routing could be helpful, though.

Lower bars means that the cables would be shorter than stock.  And, to behave as stock, less reach needed.  The excess length has to wad up somewhere and that usually means a smaller bend radius will occur.

It could be that you just need to lube them, using a dry lubricant.  I would not recomend a "wet" lube as it may soften the inner nylon or teflon friction core.  I have used a product called Dri slide.  While it installs wet, it doesn't stay that way for long.
Remove the cables and hang them vertically, over a catch pan of some sort.  Poke a hole in the corner of a small baggie and insert the top cable end into it with a rubber band sealing to the cable jacket.   The baggie makes a funnel so the Dri slide liquid can channel inside the cable jacket.  When some of the fluid comes out the bottom work the cable and twist the inner component to more evenly distribute the lube inside the jacket.  Rubber gloves are recommended.

Let it sit overnight to drain and dry out.  The carrier solvent in the lube will evaporate leaving the dry lube in place.

Clean off the outside of the cables and reinstall.  You might even try to the point the throttle mount bends forward so one large radius is formed from that point to the frame spine left side.

I'd like to hear of the progress you make.

Cheers,

Is this a 550F? Dave is correct if so. I have a 75 550F and a 78K 550.. the K goes to the left at least on mine and the 550F on the right

[Tews19]

Your routing looks ok with the bars positioned to the right.
You should do a test to see if the throttle friction changes with the position of the bars turn left right and straight ahead.

I have to disagree with Dave about routing on the right side of frame.  Routing the cable on the same side of the throttle control will exacerbate the cable bending radius issue, as it shortens the distance between throttle and carbs.  With higher bars, right side routing could be helpful, though.

Lower bars means that the cables would be shorter than stock.  And, to behave as stock, less reach needed.  The excess length has to wad up somewhere and that usually means a smaller bend radius will occur.

It could be that you just need to lube them, using a dry lubricant.  I would not recomend a "wet" lube as it may soften the inner nylon or teflon friction core.  I have used a product called Dri slide.  While it installs wet, it doesn't stay that way for long.
Remove the cables and hang them vertically, over a catch pan of some sort.  Poke a hole in the corner of a small baggie and insert the top cable end into it with a rubber band sealing to the cable jacket.   The baggie makes a funnel so the Dri slide liquid can channel inside the cable jacket.  When some of the fluid comes out the bottom work the cable and twist the inner component to more evenly distribute the lube inside the jacket.  Rubber gloves are recommended.

Let it sit overnight to drain and dry out.  The carrier solvent in the lube will evaporate leaving the dry lube in place.

Clean off the outside of the cables and reinstall.  You might even try to the point the throttle mount bends forward so one large radius is formed from that point to the frame spine left side.

I'd like to hear of the progress you make.

Cheers,

Dave is correct if this is an F model. I have a 550F and mine go to the right as well. Due to the carbs.. My 550K 78 is on the left.

[Duanob]

F model never came with rubber gators. I would guess it's K model and the cable routing looks correct. Take the cables off the carb linkage and move them back and forth from the carb end. See if you have any stiction. If you believe the carb linkgae works fine then work your way backwards.

[quidger]

Your routing looks ok with the bars positioned to the right.
You should do a test to see if the throttle friction changes with the position of the bars turn left right and straight ahead.

I have to disagree with Dave about routing on the right side of frame.  Routing the cable on the same side of the throttle control will exacerbate the cable bending radius issue, as it shortens the distance between throttle and carbs.  With higher bars, right side routing could be helpful, though.

Lower bars means that the cables would be shorter than stock.  And, to behave as stock, less reach needed.  The excess length has to wad up somewhere and that usually means a smaller bend radius will occur.

It could be that you just need to lube them, using a dry lubricant.  I would not recomend a "wet" lube as it may soften the inner nylon or teflon friction core.  I have used a product called Dri slide.  While it installs wet, it doesn't stay that way for long.
Remove the cables and hang them vertically, over a catch pan of some sort.  Poke a hole in the corner of a small baggie and insert the top cable end into it with a rubber band sealing to the cable jacket.   The baggie makes a funnel so the Dri slide liquid can channel inside the cable jacket.  When some of the fluid comes out the bottom work the cable and twist the inner component to more evenly distribute the lube inside the jacket.  Rubber gloves are recommended.

Let it sit overnight to drain and dry out.  The carrier solvent in the lube will evaporate leaving the dry lube in place.

Clean off the outside of the cables and reinstall.  You might even try to the point the throttle mount bends forward so one large radius is formed from that point to the frame spine left side.

I'd like to hear of the progress you make.

Cheers,

Dave is correct if this is an F model. I have a 550F and mine go to the right as well. Due to the carbs.. My 550K 78 is on the left.

It'a a 1975 CB550 K1 four-into-four exhaust. I have the routed from the right (throttle grip side) across and under the headlamp shell, back across the frame to the right side of the bike and through the elongated hole in the middle of the frame.

I made this point earlier but I will reitereate - the cable snapped back fine before I took the carburetors off  to  replace the float needle assemblies and o-rings. Upon re-installation is where the problem has occured where the cable returns the carbs to the close position only with coaxing of the throttle grip.

[TwoTired]

Dave is correct if this is an F model. I have a 550F and mine go to the right as well. Due to the carbs.. My 550K 78 is on the left.

No.  Check out the Honda shop manual chapter 16 supplement, pg 167.
The F model cables are shown to route on the left side of the frame.

I have found that all the 550's route best that way on all models.

F model never came with rubber gators.

Both the 75 and 76 F models left the factory with fork gators.  It was only the 77 model that did not.  In fact, all Cb550 models in the US lost the gators in 77.

[Duanob]

F model never came with rubber gators.

Both the 75 and 76 F models left the factory with fork gators.  It was only the 77 model that did not.  In fact, all Cb550 models in the US lost the gators in 77.

I stand corrected. I've just never seen an F model 550 with them. But he does have the 550K headlight ears. F model had the signal stem mounted where the reflectors do on the K model.

[TwoTired]

It'a a 1975 CB550 K1 four-into-four exhaust. I have the routed from the right (throttle grip side) across and under the headlamp shell, back across the frame to the right side of the bike and through the elongated hole in the middle of the frame.

I made this point earlier but I will reitereate - the cable snapped back fine before I took the carburetors off  to  replace the float needle assemblies and o-rings. Upon re-installation is where the problem has occured where the cable returns the carbs to the close position only with coaxing of the throttle grip.

Are you using the stock return spring?
Are you leaving enough slack in the cables so that the twist grip rotates 1/8 to 1/4 inch before the carb slides move?

[quidger]

It'a a 1975 CB550 K1 four-into-four exhaust. I have the routed from the right (throttle grip side) across and under the headlamp shell, back across the frame to the right side of the bike and through the elongated hole in the middle of the frame.

I made this point earlier but I will reitereate - the cable snapped back fine before I took the carburetors off  to  replace the float needle assemblies and o-rings. Upon re-installation is where the problem has occured where the cable returns the carbs to the close position only with coaxing of the throttle grip.

Are you using the stock return spring?
Are you leaving enough slack in the cables so that the twist grip rotates 1/8 to 1/4 inch before the carb slides move?

Yes. Stock return spring on the carburetor linkage. When I operate the linkage manually the spring snaps back with very good force. It's just when the cables are attached that the drag on the linkage occurs.
I am leaving some slack in the cables at the twist grip. No matter how I turn the adjuster on the pull cable - either all the way out or all the way in - I never seem to be able to get all of the slack out of the cable. In other words, they are never taut or under tension.

[Lars]

As I suggested earlier - disconnect the the lower cable, does it work nice now? I have had the same problem once, I it was due to poor adjustment on the cables, too tight.