Throttle Problems

[Bauer]

Hey all.

Well, murphys law has struck so to speak. I just bought the superbike handlebars for my 80 special (stock pull backs were way to sharp and hurt my wrists) While mounting them and rerouting cables and wires, something happened with my throttle cable.

1. It was never kinked, or had sharp curves put in it.

2. Bike worked fine last weekend.

I got everything put together this afternoon and was going to take it for a quick spin to see how I liked the new bars. I put it on full choke (its about 30-35 degrees out) and hit the starter, cranked a time or two and fired. All fine and dandy right. Ran it on full choke like I usually do, till it starts idleing up, and then kicked in down to half choke. It took off on me like a bat outa hell. I had to hit the kill switch to keep from revving into dangerous zones. At this point, I still had not twisted the throttle, though I had been twisting it with the engine off before firing it up.

I was thinking that the cable was sticking, seeing as the throttle would not return unless I turned the twist back manually. So I took it off the bars, pulled it so that it was as straight as possible, and it still appears to be sticking, but while watching and pushing on the springs on the carbs. it appears to be returing to zero, though it still idles way up. It worked perfectly fine in similar temps last weekend.

SO, my question lies in. Is something sticking inside the carbs, that is causing the bike to idle way up without seemingly having an end. Or is it more than likely the cable, Im going to oil the cable first chance I get tom. but would like some input on other options that may be wrong.

Also, how can I take the cable off the twist, I need to be able to route the cable better....

Thanks for the help.

[strom]

Might be easier to take the cable off the carbs. I installed a tad higher handlebars (Z900) and it was all fine and dandy. I installed a new set of grips later, but they were a bit shorter than the humongus ones I had on before. It was only bout 1/2 cm, but it was enough. Throttle was fine and dandy, but when I rode the bike out of the garage, turned the handlebars to far left, revs went sky-hi. Reinstalled the prev. grips.
Check the carb clamp thingies that hold them to the intake rubber thingies... if not set properly, they can obstruct the throttle cable mount on the carbs.
And I doubt it's an inside job.

Good luck and let us know what you come up with.

LP

[LoserShoes]

Did you forget to put back that little clamp thingie under the twist grip that holds the 90 degree elbow thingie in place? Could slip and lengthen your throttle cable.

Steve

[TopCatGr58]

You Slacker!

Hey Bauer,

There is a slack adjuster on the handlebar end of the cable, and after changing the route of the cable, you may have altered the tension on the cable in relation to the sleeve? To take the cabel off the grip, you unscrew the 2 screws that hold the control switch assembly and this will then expose the twist grip assembly where you can the remove the cable. Also, loosen the tension adjuster at the grip 90 degree metal portion, then also verify as said before that the butterfly throttle plate isn't hanging on the air intakes clamps and such. IIRC, Yamaha recommended about a 1/4" slack in the throttle cable tension to allow for tightening during the turning of the bars, like what Strom experienced!
T.C.

[Pat Kelly]

Here's a photo of the cable routing on my LG with superbike bars:

Here's the throttle cable pointing forward off the control. It loops around and heads down the left side of the frame. When I 1st installed the bars the engine would rev when the bars were turned left, Now no problem.


Here's my clutch cable routing:

[GNEPIG]

.. it sounds like everyone has covered all the good posibilities here and by the way nice pictures Pat.. i have one to add also, if you push your throttle grip/switch housing assembly too far onto the end of the handle bar, the very end of the grip/throttle sleave will cause resistance on the end of your handle bar. so make sure your throttle/ grip has the side to side play as well as the proper cable end play.. loosen the throttle assembly screws a little and slide the assembly to the right just about 1/16 of an inch
..hope this helps

[Bauer]

I dont appear to have a problem in relation to the handle bar posistion, but it does stick, But I do notice that the 90degree metal portion is parallel with the handlebars rather than perpendicular, I thought it slipped when I was taking it apart, but wasnt sure.

I unfortunately had no time to even look at it today, but will be working on it more tom.

Does anybody have the exact instructions for removing both the clutch and throttle cables off the grip ends? Clymers seemed to completely miss the throttle cable info. I was not happy.

I had the throttle assembly apart, but did not remove the cable, when you slide the round end (that the cable attaches to) out of the throttle assembly, does the cable simply slide out the bottom with the metal arm, or how exactly does it come apart from that point on?


Thanks for all the great ideas, at least I have a point to start with now.

[TopCatGr58]

Originally posted by Bauer
I had the throttle assembly apart, but did not remove the cable, when you slide the round end (that the cable attaches to) out of the throttle assembly, does the cable simply slide out the bottom with the metal arm, or how exactly does it come apart from that point on?


Thanks for all the great ideas, at least I have a point to start with now.

Once you unscrew the locking screw and clamp that holds the elbow into the handle, the cable slides right out of the handle, clamping round end and all.

The clutch can be a little more fun. You'll need to turn the slack adjusting knob/lock in towards the clutch lever to create more slack in the cable. Now, you can either take the engine clutch adjuster cover off, and pull the clutch lever in all the way, then wedge something(piece of wood?) to help hold the actuating lever in the pulled position so you can have lots of slack at the handlebar to be able to pull the cable out thru the aligned slot in the adjuster, and then rotate the cable to align it with the slot in the lever to slide the round end out.

OR...don't mess with the engine cover, with the minimal amount of slack you have created at the lever, pull the clutch lever, then quickly release the lever while pulling the SLEEVE out of the adjuster so that it is wedged on the end of the adjuster, you may need to then pull the lever again to give you more temporary slack, then repeat the release and finally get the cable out of the lever holder, and then the lever itself. To put it back in, you get to pull on the cable sleeve to give you enough slack to get it to slide back into the slot and back into the adjuster!!
Have fun!
T.C.

[Bauer]

Thanks for the pics Pat.

I rerouted the cables according to Pat Kellys pics, and it did the trick. Put the tank on and started it up, no problems with the throttle at left/center/right and the throttle is no longer sticking at the grip. A little oil helped that out alot. Ill get some pics of the new bars put up in a bit.


Thanks for the help everybody.

[Bauer]

Handlebars Side By Side


Rise of OEM Bars


Working on cable placement






Hope this works...

[Bauer]

Pat, one quick question, you obviously didnt run the clutch cable up through the hole by the ignition, but off the right side of the forks, where exactly did you run it there? Do you have a pic, I tried several ways, but nothing seemed to come out like yours. So far I have it coming up by the ignition and then across the speedo to the clutch lever. It works, but I dont like how it is putting pressure on the speedometer.


Thanks.

[Bauer]

A final pic....

Clutch and throttle cable routing

[Pat Kelly]

My clutch cable goes from the handlebar lever, between the handlebar and speedo and around between the right headlight ear and the speedo. It then loops down along the right side of the steering head, under the tank and down to the clutch.
If you look at the 2nd photo you see it going below both gauges, not between.
I have no problems at all routed this way

[Bauer]

Ah, so that is the way I had it routed, It didnt seem to want to work that way, May have to try it again.

Thanks.