Throttle Lock-ST1100

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Re: Throttle Lock

You have probably considered this already but have you tried 'spraying' some powdered graphite at the ends of the twist grip at the switch block and bar end weight. I had a similar experience to you the graphite lubricated the ends of the grip and it returned normally.
I've even shortened the grip so that there is no contact between the components on either end. My problem is that the coiled return spring at the carburetor has lost its... well... "spring," and is not returning back to "full off." I can twist the throttle off (forward) more than the spring will pull it, and the bike will drop idle even further. I've been inside there and have seen what is going on. The idle adjustment screw is completely retracted and is not even contacting the stop on the bell-crank at the carbs. I've checked for any cable kink or routing problems... I've lube the heck out of both ends of the cables and they appear to be moving in and out without restrictions. It's just that in order to get to that goofy spring (to replace or simply re-tighten) I've got to pull the carbs off, because that bell-crank piece is right up against a piece of frame.

At this point, I'm considering just rigging a supplemental return spring, if I can find a way to connect it to that bell-crank. Otherwise I'll live with it until the need for a major carburetor rebuild.
 
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John OoSTerhuis

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Sounds to me like you've simply got one or both of your throttle cables too tight. Back them off and see if that returns normal spring return tension/function. Then snug them back up incrementally until you get the desired throttle take up slack.

Or... you've got some problem inside the handlebar housing...(?)

Edit: just a delayed thought: is the right end of the throttle grip rubbing on the bar-end weight, restricting movement? BTDT on all my installs. I added a washer/spacer on its bolt to extend the weight out a bit to fix the problem.

John
 
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Sounds to me like you've simply got one or both of your throttle cables too tight. Back them off and see if that returns normal spring return tension/function. Then snug them back up incrementally until you get the desired throttle take up slack.

Or... you've got some problem inside the handlebar housing...(?)

Edit: just a delayed thought: is the right end of the throttle grip rubbing on the bar-end weight, restricting movement? BTDT on all my installs. I added a washer/spacer on its bolt to extend the weight out a bit to fix the problem.

John
I've got the right amount of slack in the cables... I've adjusted them in and out several times hoping that would be the fix. The throttle sleeve on the handlebar slides freely, even from side to side a bit, so I assume there is nothing binding on it. I've even shortened (cut) the rubber grips (mostly to make room for the Vista-Cruise - but the problem existed even before its recent installation), so there is no binding on either end. I will say that my lubrication has been with WD-40 and not dry graphite, but that shouldn't be a problem.

In looking at some other pictures of the carb assembly off the bike, there appear to be multiple instances of this "coiled" spring that return the butterflies to closed... so perhaps one or more of them have broken, and I'm expecting the only one I can see (at the bell-crank/cable connection) to be doing the entire job?
 
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John OoSTerhuis

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....the problem existed even before its recent installation ....
Ah... that pretty much rules out VC install then, which distracted me. Which now leaves me at a loss for diagnosing further, Jim. Random thought: do you have handlebar risers installed?

BTW, throttle cables should not be lubricated internally with anything. And the Vista Cruise should not have any lube of any kind applied to any of its parts either.

Anyway, if you actually have a throttle bellcrank return spring failure, it would be the firST I've ever heard in 18+ years on the forums. Something is kinked, binding etc or otherwise restricting the movement of the cables/bellcrank. IMO

You can further inspect the system without removing the carbs. BTDT Just pull the fuel tank (4 bolts, left side and top connectors). Two bolts on the bracket above the bellcrank holding both throttle cables will give you the slack to remove the swagged ends of the cables from the bellcrank. Then you can check the return spring. If that seems normal (strong), move 'upstream.' To check the movement of the cables inside their housings, I'd open the handlebar housing to get to the other end of them and test for free sliding of each, individually.

Here's some carb pictures that may be of help/interest: http://www.st-riders.net/coppermine/thumbnails.php?album=40

OK. That's all I've got. Good luck.

John
 
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OK. That's all I've got. Good luck.

John
Yeah, I've had the cover off a couple times and have gotten all the way down to a visual inspection of the bell-crank... just haven't gone any further. I do have handlebar risers installed, but I have also re-routed the cables behind the triple-clamp as a result. They have nothing binding them that I can see or feel - plenty of slack (which I cannot say for the wiring harness to the Police Switches on the right side - but I'm not using any of them at the moment). I did pickup a couple odd springs at Ace Hardware this morning (I was there on another matter) and I may take a look deeper next weekend. For now, things are working... and it's supposed to be 80 degrees tomorrow... so instead of tearing the bike down... I ride!

Thanx for the insight.
(And apologies to the OP for the brief hijack)

Jim
 

John OoSTerhuis

Life Is Good!
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Bettendorf, Iowa
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1991 SSMST1100
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I did pickup a couple odd springs at Ace Hardware this morning
Another thought: all four carbs have return springs in the interconnected linkages. Inspect all linkages for something binding, rubbing, bent, etc.... BTW, I couldn't definitively ID the part number for these springs (item 10, 12, or ? here?: linky.

Mods, clip these poSTs out into their own thread if deemed fit.

John
 
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