Triumphrat

tonupdave

On a Thruxton you could fit a Doherty replca type twist grip with a bit of mod. to the cables these have the friction device fitted to to the barrel only7/8 bar diam

ClimberClint

OMG! Brilliant! Not boring in the least! This is my next project. Thank you so much for sharing the details!


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Owenbrau

As always, a wonderful and informative post. Your modesty does you credit, but your tech posts are never boring even if I probably won't use it. I did discover what you said about a throttle lock stopping it; I have the Kaoko Cruise Control (NewBonneville.com), and in the process of installing it and getting it to work, wound up taking all that play out without even realizing it. It operates by putting pressure on the end of the throttle tube, so that had to be adjusted until it would slide smoothly when lock was not engaged, while holding it when it was. I also put gel grips on, and hand numbness even on long rides is a thing of the past.

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GDCobra

I guess if that were seen as a problem one could cut 10mm off the end of the h'bar and use a 5mm spacer instead of 15 so keeping twist-grip in the same position.
You could also use the same mod for 1" h'bars using the same bearing by machining up a bush with ID equal to the bearing OD and OD equal to the throttle sleeve ID.
I'd be tempted to look at making up a PTFE sleeve for the inner end of the twist girp.
I'd also leave the thread at 5mm also rather than modify it.

Do you feel a benefit to your riding or is it more a case of feeling more sophisticated?

Forchetto

Thanks for your comments. Once long term testing is completed I might do what you suggest: cut a bit off the bars and shorten the spacer.

I had already drilled and tapped the threaded bar insert to experiment with different bar-end weights. If I hadn't, then I would need a bearing with a smaller inner race diameter and I couldn't see any in the bearing listings. The closest was 7mm ID and I made up the difference between the M6 bolt and those 7mm with a plastic sleeve made, once more, out of a short piece of heat shrinkable sleeving.

The previous experiment involved a much heavier weight and the "Throttle wank" mod, and that worked well. I'm now running with more or less the standard weight and the wank mod.

I may increase the bar-end weight a little, as this morning I got a twitch of sleepy hand after about 80 km. The throttle action is a bit smoother and feels more precise and controllable when negociating slippery surfaces like fallen leaves and twigs at this time of year. It could be a placebo effect I suppose, but it does feel nice. I've always kept things like the throttle cables, mechanism, cam and sleeve well greased anyway, so the improvement is marginal.

GDCobra

Well my thoughts were that I'd make the spacer stepped so that it has a diameter to engage with the inner race and a close fit hole in the centre for the bolt so allowing the bar thread to remain unchanged (but if you'd already made modifications that's a good reason why not) and also centring the assembly.

Yeah, best to keep wanking and throttle control for separate times, I may have a look into something similar over the winter if I can get a few other projects out of the way.