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Discussion Starter #1 (Edited)
I thought I had the definitive solution to my throttle hand going to sleep by fitting a much heavier bar-end weight and, indeed, this was so up to the relatively short runs I had been doing. However this Summer I did some much longer runs and the problem cropped up again.

Tried different weights again, checked throttle body balance, tightness of engine and exhaust mountings to ascertain if these sources of extra vibration could be causing it but no results.

I then remembered member Aarik's contribution to my previous thread about this problem, and the advice and mod that his mechanic had given him. This involved removing all sideways movement of the throttle sleeve. He even called it "Throttle wank", a very apt description of the action of said sleeve. The mechanic gave him no clues as to how he achieved this though, treating it as a "trade secret".

Here's the thread where this was discussed. The first clue comes up early on post 5 from M.G.Vig where he found that his throttle cruise control stopped it. This could easily be due to the fact that these crusise controls often work in a way that they stop the grip from moving at all in any direction when engaged. Aarik then tells us about the cure on post 17 and was then later confirmed by thruxton09 on post 37:

http://www.triumphrat.net/twins-technical-talk/181290-throttle-hand-going-to-sleep.html

At the time I took this with a pinch of salt, not because I didn't believe it, but because after 42 years motorcycling I had never heard of it. Even now an exhaustive Google search finds no mentions of this simple cure and cheap (well free really) to a considerable problem, to judge by how many riders complain about it. This thread will soon become available on Google searches so more people will get to know about it, hopefully.

I have now followed that advice and find it works really well, at least on my last 120km run my hand didn't go to sleep at all. I'm amazed...

The idea is to remove all the sideways movement of the sleeve, that's the axial play. The radial play already has Factory limits that can be adjusted with the cable adjusters, this being 2-3 mm, although I usually recommend that most or all this play be removed consistent with no change in engine idle speed being apparent when turning the bars from side to side. I find this minimises throttle snatch and helps smooth gear changing.

There are various ways to do this.

The photo shows 2 of them:

1.- Undo the two screws that hold the whole throttle mechanism and move the whole thing closer to the bar-end
weight until it just touches, then a little more until all play is taken up. Re-tighten and check that the throttle return spring is still able to bring the throttle to a closed position OK.

2.- Drop one or more 20x2 mm "O" rings in the space between the bar-end weight and the end of the handgrip. This
fills the space and removes the side play. This is what I've done for now as I'm still experimenting.



The proper, elegant way would be for the play to be eliminated at source by inserting one or more greased plastic "shims" inside the throttle housing to fill-up the space the causes the movement. These would be slipped over the bare sleeve and would then form an integral part of the mechanism. To do this I would have to remove the twistgrip rubber grip which in my case incorporates the grip heater and could possibly damage it, I decided to leave this until such time as the rubber has to be changed.

These photos show roughly what I mean:



 

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i use one of these;
http://www.crampbuster.com/
when i get bored sell and buy another bike it goes on the new one.
some bikes you just have to change the throttle return spring cause it's so dam strong !!!
i owned a fjr1300 a while back with an electronic/vacumn cruise control. that was luxury,it spioled me rotten. i found myself even using it on the back roads.
 

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Ernesto, Then, as I understand this, we are talking about removing the lateral movement of the throttle grip/tube on the handlebar........correct? The Meister
 

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Discussion Starter #4
Ernesto, Then, as I understand this, we are talking about removing the lateral movement of the throttle grip/tube on the handlebar........correct? The Meister
Yes. Doesn't sound as if it would work but it does.

I now have mine so that there's no lateral play at all and only a small amount of friction, but not enough to stop the grip from returning on its own.
 

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i use one of these;
http://www.crampbuster.com/
when i get bored sell and buy another bike it goes on the new one.
some bikes you just have to change the throttle return spring cause it's so dam strong !!!
i owned a fjr1300 a while back with an electronic/vacumn cruise control. that was luxury,it spioled me rotten. i found myself even using it on the back roads.
You know, I'm not sure I needed to know that you cure your 'throttle wank' with a crampbuster....
 

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Ok, thanks once again to Forchetto for bringing to my attention a totally awesome fix. I'm only mad that I didn't do it earlier. I have a 45 minute ride to and from work, and I always get a numb right hand. Did the fix Forchetto recommends above last night, and VOILA! No numb hand today. I'll report if that changes, but I am pretty happy.

I was pretty bugged last night when I stripped out the head of one of the stupid phillips screws on the back of my throttle assembly. But no worries, finally got it out and replaced with hex bolts.
 

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One mod I found to really aid overall throttle smoothness is an eccentric throttle wheel.
It makes throttle extremely precise at low throttle openings and gradually makes it more aggressive.
 

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Georider, did you use the wheel in the photo. Which size did you use? Do you have a single or double cable set up?
I haven't done this mod yet on my Thruxton because it is still under warranty and over here Triumph voids it if any modification is made.
I have done this in all my previous bikes, usually with parts from Yoshimura

.:.
Some times I just modify the stock throttle wheel, it is easy. Just offset the pivot point so the bigger radius (the distance from the pivot point to the throttle cable) stays to the side of the "pulling when accelerating" cable.
Offsetting it by 2 or 3 mm makes a big difference.
To add a bit of bling and/or visual performance one can have the stock throttle wheel anodised gold or red, or powder coated.
I've always used a double cable set up.
Getting one of aprox same size as stock, a little bigger in the beginning of the throttle action and a bit smaller at the end is the best choice for road use.

I'm thinking of starting with one of these and offsetting the pivot point


(type "throttle drum" on ebay)


You will not believe how this simple mod transform the ride:
Super smooth "fuelling", responsive throttle around town and ultra fast, crisp response when you need it, the bike will feel like it has extra power.
"The eccentric (ie. off-center) throttle wheel makes the travel of the throttle cable down low in the rev range longer and gives you more control, and makes the travel up high shorter for instant throttle response."


This will be (one) of my winter projects, along with the AI removal (now it's just blocked), turn signal/shift warn vibrating motor and a few other small but effective mods.
I can't wait !
 
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