Throttle cable

PostPost by: alfert » Sat Aug 27, 2011 4:27 pm

I am going nuts trying to get the throttle cable to behave properly. The car runs great with bonnet off. The carbs are set properly, etc. idles at 1000rpm, drops off properly etc. As soon as I start to lower the bonnet, I can see the carb linkage move and rpm increases. when completely closed, it sticks all the time. I have built a bridge between carbs and installed a spring, no better. I have lubed the cable, no better. Take bonnet off and it is great. I bought the TTR linkage, but it looks like the pedal response would not be good as spring is soo big! HELP, is there a reasonable solution to this?
Thanks,
Brian
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PostPost by: ardee_selby » Sat Aug 27, 2011 4:59 pm

Brian,

Just to be clear...I guess you're talking about a LHD car. But you use "bonnet" rather than "hood" so maybe not...

Whatever, have you a photo sans bonnet/hood?

Cheers - Richard
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PostPost by: alfert » Sat Aug 27, 2011 5:06 pm

It is a left hand drive car. I was just trying to be PC, but everything is new and stock. I am thinking of trying to find a new, less stiff outer cable housing. Otherwise I couls just cut a slot in the hood and let the cable stand tall where it works just fine...........
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PostPost by: ardee_selby » Sat Aug 27, 2011 5:12 pm

alfert wrote:It is a left hand drive car. I was just trying to be PC, but everything is new and stock. I am thinking of trying to find a new, less stiff outer cable housing


Apart from, possibly, being a bit too stiff ( :roll: ) could it also be a bit too long? ( :roll: :roll: )

alfert wrote: Otherwise I couls just cut a slot in the hood and let the cable stand tall where it works just fine...........


Excellent! Get in first, before some smart*rse does!

Cheers - Richard
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PostPost by: bast0n » Sat Aug 27, 2011 5:31 pm

Try this...............

Image

Image

Image


Works brilliantly and gets around the extortionate prices of TT et all - so simple to make an so smooth to use.

D
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PostPost by: GrUmPyBoDgEr » Sat Aug 27, 2011 9:20 pm

Are you using the TTR cable as well?

I'm not sure about the latest standard of cable supplied by them but the stuff I got gave a very poor & stiff throttle response.

If you use a good quality nylon lined bike cable the response/feel/load improves immeasurably.

With regard to your bonnet open/closed problem I think you need to look at your cable run & check what is influencing the system.

The additional return spring is there as a racing/scrutineering requirement, using just the carb' return springs will produce a light throttle pedal but your right foot will need to be correctly calibrated to prevent the "kangaroo" effect which can easily be induced.

John
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PostPost by: FOX5D » Sat Aug 27, 2011 9:38 pm

I have the TTR twin cable setup in my S3 and it works beautifully. BUT, you do have to cut a small section of the bonnet cross strengthening bit out. It's not a problem and doesn't affect anything other than to make the TTR solution work well. If you were to ring TTR, they would just tell you to do this.

Hope this helps-it works for me.

Cheers

Jim
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PostPost by: StressCraxx » Sun Aug 28, 2011 4:16 am

Brian,

Have you thought about coming up from underneath with the throttle cable? I have a bracket between the manifold studs between the carbs, underneath. The cable goes across the firewall, down, and under. The cable pulls the weber linkage down. May or may not work well for RHD. Photos taken, but I guess I'm not authorized to post. Will email on request.
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PostPost by: gjz30075 » Sun Aug 28, 2011 11:08 am

Indeed, as John said, a bike cable works great. However, for lhd cars the cable should be held down by a by a small sheet metal piece that is held by one of the cam cover nuts. Maybe someone has a pic; the cable snaps into it and it is held just a few inches above the cam cover.

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PostPost by: slimromeo » Sun Aug 28, 2011 11:47 am

ive been having problems with my throttle cable too, even after alot adjusting, greasing and many cable ties still no joy. Then after comparing my throttle to a friends he suggested changing the angle of were the end of the cable inner cable attatches to the airbox plate, mine was running straight down but now is on a pitch towards the airbox and is working perfectly.
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PostPost by: jk952 » Sun Aug 28, 2011 1:41 pm

...thoughts...
I used a nylon lined bicycle cable, the one end fitting perfectly in the air box. Do you have the std. linkage pivot at the cable sheath and is it free enough to rotate a bit, and standard air box? I set the length of the cable by pressing the throttle plate to full and leaving a bit of slack for engine vibration, clearance for a smooth arc over the engine etc. Sticks up a bit when the hood is off but is flexible enough to move a bit sideways (aft in vehicle) when the hood is down. I didn't cut out any ribs. This movement shouldn't change the throttle position unless the cable is too stiff or too long. Since the sheath does the throttle movement the stiffness is likely your problem...well from what I can surmise from here... :?

Since my carbs were new, they have an extra threaded boss on the side, which I noticed fouled the big spring, so I bent the actuator lever on the carb just a bit sideways ( forward in vehicle direction) for it to clear.
(this is of course after it stuck once while running in the driveway, fortunately I could reach the key quickly to kill it!)
LHD vehicle.
Jack
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PostPost by: alfert » Sun Aug 28, 2011 2:36 pm

This is a left hand drive car. I would be interested in any pictures. The car has the standard airbox and the cable is basically straight down to the connection, and the linkage can swivel where the cable sheath rests. The carbs are new and I had to deal with the extra ear on the side fouling the stock return spring. I seems to me that the cable and sheath are either too long or too stiff. Also I have the metal piece that is held by the cam cover. It does not help......
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PostPost by: alfert » Sun Aug 28, 2011 2:37 pm

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PostPost by: slimromeo » Sun Aug 28, 2011 5:56 pm

alfert wrote:This is a left hand drive car. I would be interested in any pictures. The car has the standard airbox and the cable is basically straight down to the connection, and the linkage can swivel where the cable sheath rests. The carbs are new and I had to deal with the extra ear on the side fouling the stock return spring. I seems to me that the cable and sheath are either too long or too stiff. Also I have the metal piece that is held by the cam cover. It does not help......



mine was straight down too but after drilling another hole about 1inch towards the airbox and slotting the cable end in it did the job. i'm so suprised of the difference it has made, its easy and cost free so you've got nothing to lose if it doesn't work. i'll take some pics tomorrow if it helps.

Franco
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PostPost by: mac5777 » Sun Aug 28, 2011 7:51 pm

Here is what I have been using from RD Enterprises with new bike cable with a clip that holds the cable down off the bonnet. You can see it near the oil cap. I had to grind off some of the metal on the throttle arm as it would contact, at full throttle, the bracing of the bonnet. It now works the way it was intended. I like the new design for the right hand drive set up.

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