Author Topic: Throttle Cable / Carb issue? *Victory! (Read 23650 times)

stormi · « **on:** May 03, 2006, 02:50:40 PM »

Grr,.. one thing after another with Dita this spring. Got the new Gear shift Link rod in, now she's doing other things.

I got a set of straighter bars ( meaning,.. that I hadn't bent by dropping her.

) and put them on. The bars have a lower rise than the original ones, and are the same length.

According to the wiring diagrams in the service manual, we've routed the cables right, but she races if you turn the bars to the right lock.

Taking everything apart, and routing cables the wrong way ( I know, I know.

) in order to troubleshoot, we notice a few things:

1. Until the cable gets to the fork area, there's no problem with binding.
2. Tank on or off, the engine still races if you route it the way the book says, or any other way.
3. Bar position (rolled forward, rolled back) makes little to no difference
4. You can actually watch the throttle get pulled at the carb end, when you move the bars to the right.
5. Certain routings allow her to race the engine no matter the position of the bars.
6. There's ZERO free play. There's no room for adjustment on the carb side or the grip side.

It's as if the cable shrunk overnight. But they're supposed to stretch, no?

The cable is lubed, and moving freely.

We're at a loss to explain this, and getting more and more frustrated by the moment. ( I actually hit her tank and called her a b*tch. My little lady!

Ok,.. it was the end of day 2 at this, and I was tired of watching her put together right, and racing to 8k rpm as soon as we started her, with a not even broken in engine.) Now, neither of us has touched her in 2 days, and both of us have started looking for reasons not to.

I know, deep down that it's something simple, and stupid. Suggestions? Is there adjustment on the carb anywhere that might be doing this? Besides the idle screw, and the nut/bolt combo for the cable itself? The service manual is vague about this area.

I can post pictures this evening if needed.

Red01 · « **Reply #1 on:** May 03, 2006, 03:10:07 PM »

Sounds like you need to observe where the cable is getting caught in right lock situations and route it to prevent that from happening.

Had a similar situation with my little 50 I bought for the grandkids. First time I started it and took it for a spin around the yard, the motor started screaming the first time the bars were turned left. Seems the factory had misrouted the throttle cable. Had to pop the tank off and correct the issue.

interfuse · « **Reply #2 on:** May 03, 2006, 03:30:24 PM »

Got the nut on the right side? I f'd that up before...

stormi · « **Reply #3 on:** May 03, 2006, 03:50:20 PM »

Quote from: "Red01"

Sounds like you need to observe where the cable is getting caught in right lock situations and route it to prevent that from happening.

That's the frustrating part. We have been looking. It seems to be when the cable goes through the triples, but no matter what angle we try to use, it seems to only change the problem slightly. It seems like it binds up where the cable makes the right at the front of the triples, to go to the grip.

The amount of cable that lives outside the cable sheathing, once the cable is hooked to the carb end, seems too short to hook up to the grip. So you have to give it a little tug to get it onto the grip, and this is with the adjustment all the way in, for maximum free play.

If you put the bars straight, and "blip" the throttle, it will settle down to the stop on the carb. If you turn the bars, it may even stay there. If you blip the throttle when the bars are turned, it will race, and you have to turn the bars back to center to get it to drop.

About the only way I seem to be able to route it so it doesn't do this is to route it straight out the right side of the bike from the carbs, and then up to the throttle grip. Of course that doesn't work for obvious reasons.

stormi · « **Reply #4 on:** May 03, 2006, 03:55:14 PM »

Quote from: "interfuse"

Got the nut on the right side? I f'd that up before...

Which side is correct? Bottom, right?

I was sure it went on the top (10 speed bike style), the other half thought the bottom. The bottom maximizes free play, the top allows more adjustment, but also holds the throttle open a little as this cable is right now.

Where it is currently, is at the bottom, nice and snug in the openning that seems made for it.

edit: in fact: This -is- Dita, and it shows it on the bottom, but it doesn't look like it's nestled into the spot that I mentioned.:

Red01 · « **Reply #5 on:** May 03, 2006, 05:15:53 PM »

The cable shouldn't have that little kink going on... it should be a striaght pull!

stormi · « **Reply #6 on:** May 03, 2006, 06:22:55 PM »

Quote from: "Red01"

The cable shouldn't have that little kink going on... it should be a striaght pull!

Which kink? At the bottom,.. or at the top where it heads toward the grip?

Poor girl.

The one at the bottom sort of indicates some slack - that's not there anymore.

The nut being off kilter at the top is due to the tank resting on it.

I object to this design, btw.

That's an old pic, from the choke cable how to I posted a while back,.. but nothing's changed (except the slack).

interfuse · « **Reply #7 on:** May 03, 2006, 11:14:41 PM »

Quote from: "stormi"

Which side is correct? Bottom, right?

I honestly can't remember but your logic for the bottom sounds good. You screwed the top nut at the carb all the way in? That top nut is adjustable as well.

If that doesn't work then try using a cable stretcher. <jk>

stormi · « **Reply #8 on:** May 04, 2006, 12:24:19 AM »

Quote from: "interfuse"

Quote from: "stormi"
Which side is correct? Bottom, right?

I honestly can't remember but your logic for the bottom sounds good. You screwed the top nut at the carb all the way in? That top nut is adjustable as well.

If that doesn't work then try using a cable stretcher. <jk>

Yup,.. it's screwed all the way into the bottom.

nope,.. last time I used a "cable stretcher", the cable got ripped in half.

erik · « **Reply #9 on:** May 04, 2006, 04:37:11 AM »

My bike does the same thing, turn it to the right and twist the throttle and it doesn't go back to idle. It seems to do the opposite when turning to the left too - the engine dies (but I only notice it when arriving home and turning around in the driveway which faces downhill, so that might have something to do with it?).
I'll keep an eye on this thread to see if you figure it out...

I'm not sure if it did it when I first got the bike. I oiled the cable shortly after getting it and I've been wondering if the oil might've made the cable stick more and prevent the throttle spring from closeing the carbs?

Red01 · « **Reply #10 on:** May 04, 2006, 12:13:49 PM »

In your picture, I can only see the wire rope of one cable, and it looks off kilter.

interfuse · « **Reply #11 on:** May 04, 2006, 01:18:43 PM »

Take a look at Jays gigantic carb pics. See how much threaded rod sticks below? Your picture doesn't show that. Check to make sure you have that adjusted properly.

http://forums.banditalley.net/viewtopic.php?t=5412

magicGoose · « **Reply #12 on:** May 04, 2006, 02:20:18 PM »

Jay's pics are of his race carbs, that's why they have more thread sticking out the bottom. HOWEVER, it doesn't look to me like the nut is tight enough in the picture. The threaded bit is a loose fit in that support on the carb, so if there is any free play, then turning your bars will pull the cable housing, causing the threaded bit to skew and open the throttle. Make sure the threaded bit is tight and not moving at all.

stormi · « **Reply #13 on:** May 04, 2006, 03:32:55 PM »

Quote from: "Red01"

In your picture, I can only see the wire rope of one cable, and it looks off kilter.

The funny part of this is that the pic is of the carbs when they were working. That's one of the pictures of the "How to build your own throttle cable" thread from a while back.

These days, everything is tight, the bolt is screwed right to the bottom, and the nut is tight against it, no room for movement. The cable is now tight, no more kink.

I'll try to step out there today and take a current picture.

(BTW, the B4 only has one throttle cable. It's not a push/pull system, like the B6/12 or the 919)

stormi · « **Reply #14 on:** May 04, 2006, 03:38:05 PM »

Quote from: "magicGoose"

Jay's pics are of his race carbs, that's why they have more thread sticking out the bottom. HOWEVER, it doesn't look to me like the nut is tight enough in the picture. The threaded bit is a loose fit in that support on the carb, so if there is any free play, then turning your bars will pull the cable housing, causing the threaded bit to skew and open the throttle. Make sure the threaded bit is tight and not moving at all.

OK,.. I'm going to head outside then and grab a new pic. I think I confused everyone. Sorry about that.

That pic, strangely enough, was on the bike when it was working (circa 12 months ago). The current situation is that there is no free play with the "adjustment" as tight as it can go, i.e. the nut screwed up tight against the erm,... cable guide thingy, as well as tight at the grip end.

There's no kink left in the cable, since there's no slack in it at all. It's as though the cable itself shrunk maybe 5mm overnight.