Throttle cable friction

[Still CAL]

Hi all, picking up the new-to-me RT next week and I have a question about the throttle. I may be because I still have stitches in my right hand but it seemed like it took a bunch of effort to twist the throttle. I read a thread that mentioned a low-friction replacement cable back in the day that could be done under warranty, would that help? Maybe something going on with the Bowden box? Or is my messed-up hand the prob? The PO has a throttle helper installed (just a plastic paddle palm rest, I forget the name) but I don't see that helping with the twisting.

 

So should the effort be less than I'm feeling or are these bikes known for needing a heavy twist hand? Thanks.

Richard

[Selden]

I have a 1999 RT and a 2014 F700GS. Throttle effort on the GS is much lighter than for the RT. I don't think the problem is cable friction so much as return springs on the throttle bodies on the older bike.

[AndyS]

7 hours ago, Still CAL said:

Hi all, picking up the new-to-me RT next week and I have a question about the throttle. I may be because I still have stitches in my right hand but it seemed like it took a bunch of effort to twist the throttle. I read a thread that mentioned a low-friction replacement cable back in the day that could be done under warranty, would that help? Maybe something going on with the Bowden box? Or is my messed-up hand the prob? The PO has a throttle helper installed (just a plastic paddle palm rest, I forget the name) but I don't see that helping with the twisting.

 

So should the effort be less than I'm feeling or are these bikes known for needing a heavy twist hand? Thanks.

Richard

 

Which model RT are you picking up?

There are lots of reasons for heavy throttle action. Things like slightly out of round throttle grip rubbing on the handlebar, bad throttle cable routing, Trapped throttle cables, Twist grip rubber rubbing against twist grip housing, Twist Grip rubber rubbing against balance weight, dirt ingress into the bowden cables. Dirt in the twist grip housing. 

So a lot of options to look at there.

[dirtrider]

7 hours ago, Still CAL said:

Hi all, picking up the new-to-me RT next week and I have a question about the throttle. I may be because I still have stitches in my right hand but it seemed like it took a bunch of effort to twist the throttle. I read a thread that mentioned a low-friction replacement cable back in the day that could be done under warranty, would that help? Maybe something going on with the Bowden box? Or is my messed-up hand the prob? The PO has a throttle helper installed (just a plastic paddle palm rest, I forget the name) but I don't see that helping with the twisting.

 

So should the effort be less than I'm feeling or are these bikes known for needing a heavy twist hand? Thanks.

Richard

 

 

 

Morning Richard

 

As mentioned the older BMW 1100/1150 boxer bikes do have fairly heavy throttle return springs (one on each throttle body). Those stiff springs do take some getting used to if coming from a different brand motorcycle.

 

That throttle rocker that the previous owner added can also increase throttle effort as some of those can squeeze the inner plastic twist grip tube tighter on the metal handlebar tube.

 

Also, on older BMW 1100/1150 bikes there can be some grit or dirt that enters the throttle cables & that can add friction to the cables. Or grit between the plastic twist grip tube & the handlebar metal tube (especially with a throttle rocker installed).

 

Another place to look is for the entire twist grip/switch assembly to have moved on the handlebar causing friction between the outer end of the twist grip & the bar end weight.  

 

Another possibility is that someone has  used the incorrect lubrication type on the cables that has swelled the inner cable liners causing extra effort to use the throttle.

 

Or possibly the cables are adjusted too tight & that can add extra friction.  

 

BMW did offer a low-friction cable setup  for the very early 1100 bikes but that was mainly for a surging reduction. It changes the actual throttle effort at the twist grip  very little.

 

Ride your new motorcycle for a while to evaluate it, if the effort is just a bit high with no sticky feeling then it probably is what it is, if it also feels a little sticky at light throttle position changes then you can probably work on it to make it smoother.

 

You can also add something like a grip puppies as that helps your hand grip as well as increasing the twist grip diameter for a better purchase on the grip.

 

 

[Still CAL]

Thanks AndyS and dirtrider, plenty to think about. I'll see how it feels on the ride home next week.

[SAS]

+1 on rubber hand grip.