Anyone ever modify the throttle cable arm at the carbs ?

[Guest]

I'm lookinf for a different type of performance. Not all out power but smoother operation. One thing that makes it difficult to be smooth is the throttle cable free-play. If I adjust it too small, the RPMs come up when I turn to right lock. I've set just enough freeplay so the RPM increase is liveable, about to 1500 from an 1000 RPM idle speed.

Still it's very bothersome t oalways have to "feel" for the free-play to get taken up, before I can twist in enough throttle for the situation. This is especially true when I've slowed going through an intersection and then re-applying some power. It's just plain NOT smooth unless I use the clutch or take a lot of time "feeling" the free-play as described.

I'v ebeen practicing a different type of shifting technique also. I am attempting to pull the clutch in fully as I let go of the throttle which is failry normal. The difference is that I do this a split second BEFORE I shift, instead of at the same time. Then when I try to add in some power there is that little lag as the cable takes up the free-play.

I'm thinking a different arm at the carb could do me some good here. What I'd like is to have the throttle opening very slowly at fist with more than the normal amount of rotation on the twist-grip. I'm not so concerned what happens at full throttle as long as it's all there when the twist is all the way to it's normal full throttle position.

Has anybody ever herad of anything that can do this ? If it adds a few inches to the throttle cable, I'd be all for it that so I can reduce the free-play to sero if possible.

[Steve]

Why are you letting go of the throttle when you shift?

Simply hanging on to the grip and not releasing it all the way will smooth your shifting considerably.

.

[dorkburger]

Sounds like it could be a throttle cable routing or length issue.

[ozman]

Sounds like it could be a throttle cable routing or length issue.

correctly diagnosed, i believe not much else can cause the problem

[trippivot]

lock to lock steering without throttle bind is VERY VERY important. this is a safety issue. I'd suggest you fix a.s.a.p.

like the boys said, fully reroute the your cable - tank off and cable removed from twist grip. find the routing where your fully closed throttle freeplay is the same left lock and right lock.

[eil]

There's really no way to make it so that there's zero play in the throttle cable with the bars straight. Otherwise, when you turn the bars, the throttle will come up, as you experience.

My 850's throttle is pretty smooth, even just a bit smoother than the 750 which has very low miles. (But I think the majority of that comes down to the difference performance characteristics of the two.) I think you should just pay close attention to your technique, work on it, and bear in mind that you're riding a 35 year-old bike.

I'v ebeen practicing a different type of shifting technique also. I am attempting to pull the clutch in fully as I let go of the throttle which is failry normal. The difference is that I do this a split second BEFORE I shift, instead of at the same time. Then when I try to add in some power there is that little lag as the cable takes up the free-play.

As Steve alluded, I think this is a somewhat uncommon technique.

I'm not the world's shifting expert by any means, but what works best for me is operating the gearshift lever, clutch, and throttle more or less simultaneously. I never pull the clutch all the way in to upshift and I never close the throttle all the way unless coming to a stop.

[JamesWhut?]

The cable should not care what orientation the bars are at. That is why it is in the sleeve. You should be able to get nearly slack free, instantanious throttle response. If the throttle cable is moving and messing with idle when the bars are turned it means that either the sleeve is crimped and dragging on the cable, the cable is corroded (and needs to be replaced), the cable is bent at to sharp an angle, and/or the cable needs to be lubed. Try lubing the cable first to see if that clears up the problem. If not, replace it.

[tirebiter]

Don't get me wrong everybody. I can shift as smoothly as just about anybody. First learned how by driving a single cylinder street bike about 45 years ago.

There is no binding/resistance to cable movement. Had it out and rerouted several different ways, lubricated it and tired several adjustments before I settled on a 500 RPM increase at full lock right, only. If the cable sheath was about two inches longer it might be ok as far as the idle increase at full lock right. What I'm finding is at the extremely low RPMs I'm using around town, the half a millimeter free-play bugs me.

Also when picking my way around mud puddles down the dirt road to home in 1st gear, it's not easy to hold steady when the free-play gets taken up and my hand bounces on the twist grip, the engine wants to go more than I wanted it too. While stationary on the center stand, I can easily and smoothly pick 100-200 RPM additions from idle on up, in neutral. The cable is working well but it's the darn free-play I detest and the super quick throttle opening response at small throttle openings.

Also in stop and go traffic which I encounter almost every time out, the free-play keeps reminding me it's there. I'd like to be able to roll on - and off - the throttle in one gear without having to use the clutch to keep things smooth and under control. The throttle action under these conditions is just plain TOO TOUCHY for my taste.

Even if there was zero free-play, it's difficult to open (or close) the throttle a small enough increment every time, at these low RPMs. It's the 1000 to 2000 RPM range where it's the most touchy. Sometimes, I'm lugging the engine down to sub-idle speeds in 1st or 2nd gear, creeping along in traffic. The engine runs smooth and has good response but it's just plain difficult to add a small enough amount of throttle especially under these conditions. I'd rather not have to constantly shift between 1st and 2nd or neutral which seems to be the alternative or ride while dliberately slipping the clutch most of the time.

Mind you it does not go to higher RPMs than I want. It's just difficult to smoothly apply throttle from idle (especially with the free-play) and difficult to be smooth from just above idle to slightly higher.

I don't think it would be such a nuisance if the engine had considerably less torque at such low RPMs.

If I can change the ratio between twist-grip angle and throttle shaft angle just off idle, I would be a very happy camper. When trolling along at 1500 RPM in any gear, I can easily and smoothly roll on or off a small amount of throttle and the bike reacts exactly as I want. From idle, there is the sudden "GO" that happens when the throttle opens.

If I could get the throttle to open one 10th to one 50th as fast, just off of the closed position, I think I'd be ok. I know she's a relic but it still makes me want a more pleasurable ride. Other than this picky little point, I'm extremly happy with "Little Suzy" and she is providing good transport whenever I want.

I've done similar modifications with certain how powered cars and it paid off big time with muchly improved driveability at low speeds and normal traffic conditions. If anyone is interested I'll post my results with "Little Suzy" and the slow-ratio-off-idle-throttle-linkage-modification here.

I was just wondering if anyone had already figured out a good way to do this.

The odd shifting technique I've been working on is a way to train myself to cope with the super touchy throttle response at the low RPM range I am talking about.

[JamesWhut?]

What you might be describing as "touchy" might actually be a stumble from off jetting of the idle to mains circuit. Probably from too rich to too lean. That would produce a sudden surge at low RPM and has nothing to do with the throttle or cable. Easiest way to check this is to shim the needles up one washer or clip and see what that does to off idle behavior.

[Chris G]

If it's a old cable, put some lube inside it, makes for a good improvement, applies to all cables really.

[Chuck78]

500 rpm increase from straight to lock is insane! Do you have tall handlebars? This is very abnormal for a GS. as stated, you may also have a jetting issue, or dirty partially clogged pilot circuits. I am all for recommending a new & well lubricated/routed throttle cable for your bike.

Also, if you still feel that the power comes on too fast, try modifying the throttle grip's cable routing track diameter with JB Weld & a dremel. I used a thin slice of 1" PVC drain pipe cut in a "C" shape to add diameter to the throttle grip, & beveled the beginning for a smooth transition, so that I would have faster mid & high range throttle response, but transitioning off idle gradually. Not up to 1/4 turn throttle speed, but as preferred, faster reacting than the stock gs750 throttle rate. Much improved.

You would want to probably reduce the diameter of the beginning if the cable's track in the throttle grip cable slot. Heck, maybe your cable is stretched so much or the housing worn out & compressed that you have an extra differential amount between housing length & cable length, & taking up the extra feeeplay puts you further into the ramp on the cable's throttle grip track.

At any rate, what you describe is abnormal for a GS, & very dangerous unless only riding in a straight line on a dragstrip. My buddy's KZ650 did somrthing similar, & it turned out to be his throttle grip housing where the cable exited had a crack in it that was flexing & messing with cable tension. Also could be a loose 90 degree adjustable piece on the throttle grip, the noodle that the cable goes through.