Throttles up when I turn bars

Fast Eddie said:
Exactly !

Tying the splitter to the frame (or similar) definitely helps to keep twin carbs in balance.

You want as little movement as possible twixt carb and splitter, and ideally you want those cables to be as short as possible and routed identically, so the pull is always even and those individual cables do not move and stretch differently to each other.

Then having only one cable going to the handle bars means that it doesn’t matter a jot how much it stretches, it cannot effect carb balance.

Doing it in this way basically acts like a poor man’s gantry.

I don’t want to sound like a cable snob, but I see lots of bad cabling on old bikes. You can’t just throw them on and be done. Especially if using a splitter, you need to ensure that the twistgrip opens the slides all the way rather than the cable topping out in the splitter. With chokes fitted, you need to ensure the choke slide closes and opens fully. With all cables you need to ensure smooth action, avoiding tight turns and tight cable ties etc. AND you need to ensure that moving the bars does not effect the cables functions (back to the OPs issue). Personally, I spend a lot of time routing cables when building a bike and often try several ways before I’m happy.
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Thanks all for your many comments! Catching up now since my post yesterday on throttle cable increasing revs. I also spent time looking back at many related older posts for a fix.

Fast Eddie here seems to give me an answer I wanted to hear. If I summarize things correctly, it appears if I secure the splitter to the spine then the lower cable pair are in a solid position. If I can assure the single cable from the twist grip has a smooth routing and free to float, then I'm good.

I do have a solid, angle tube with slack adjuster & lock nut just off the twist grip. Currently I have that adjustment set to give me zero play (no slop) when twisting throttle off idle...I may loosen that a bit. I also assured the carb slides are synced and there is no play at the carb cable ends and at the cables in & out of the splitter.

I'll post later once I pull the tank and try again.
Dave
 
Dave,
I always adjust the play at the twist grip last and give it a little bit of play after turning the bars in both directions to make sure there is no movement with your cable routing.
Mike
 
If you are going to tie the splitter to the frame, make sure the short cables have some slack in them. Remember that the carbs are on the vibrating mass of the bike and the splitter is on the isolated mass. Then make sure you have enough cable length between the splitter and the throttle control to have a nice sweeping loop between where it emerges from the fork yokes all the way to the throttle control.

My splitter is positioned in the crotch of the frame where the headsteady brace tube meets the backbone tube. The short cables then run either side of the 1" tube, to each carb, with no stress on the cables. Basically secured by geometry. The main cable runs up on the left side of the frame, emerges below the head light, sweeps under the right headlight ear, and makes a nice gentle curve up to the throttle. It does not need to be secured any where along its length.

FWIW
 
I agree that fixing the splitter to the frame is a good idea.
The the issue with rev/turning can then only be the single cable too short or incorrectly routed.
Cheers
 
Thanks again all for your collective inputs. I think I've got it...free & loose routing to splitter (plenty of length), just a bit of free play in the twist grip (can hear the slides hit stop screws), secured splitter to frame, added sweep to thrtl & choke cables @ carb top.

I have a photo but the adding media process is unclear when I click on "Insert Image". It's probably much easier than assembling my choke cable splitter after I rerouted the short lengths this morning!! Someone said hemostats...worked awesome!

Dave
 
Fast Eddie said:
There are many cable suppliers out there and some are better than others. Lengths and dimensions can be all over the place! You shouldn’t try and draw conclusions from one set, especially of unkown origin, IMHO.
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Also, the plastic junction boxes from Amal have not changed but from others can be different. A while back I worked on a chrome-lovers bike with a chrome metal junction box. It required more free-length on the short cables and a lot more on the throttle end.
 
marshg246 said:
Also, the plastic junction boxes from Amal have not changed but from others can be different. A while back I worked on a chrome-lovers bike with a chrome metal junction box. It required more free-length on the short cables and a lot more on the throttle end.
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Very true. Add to the mix different twist grip types and it’s easy to see why folk struggle !
 
So now we need a lathe just to fit throttle cables ?!?
Edit: the post that this was a reply to has since been deleted.
 
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Desmopower said:
I had similar problems with the splitter box setup & mutliple cables, the best thing I done was to ditch the entire stock setup (choke & throttle)
I have now installed Don Pender's carb gantry - one throttle cable instead of the many.
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