woodsy144
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| posted on 29/8/23 at 12:07 PM |
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Cable clutch - ideas to improve feel
Hello all.
I took my car our for the first time over the weekend.
And while yes it has a new clutch. There was a lot of stalling........
Anyway. I would like to get some thoughts on improving clutch feel / take up as to avoid looking like a noob.
Its a 2008 R1, with a cable clutch.
See picture of pedal box, I am running standard clutch arm.
As you can see from the photo, I have the cable position in the closest hole, giving me maximum mechanical advantage.
I was hoping, by having more through I may be able to modulate it better.
Anyway love some thoughts.
Thanks.
[Edited on 1 by woodsy144]
[Edited on 1 by woodsy144]
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nick205
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| posted on 29/8/23 at 01:58 PM |
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From the marks it looks as though you've tried moving the cable to different positions - any difference?
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coyoteboy
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| posted on 29/8/23 at 02:46 PM |
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What's the problem you're experiencing? You shouldn't really be able to feel the cable aspect other than maybe a little friction, so
the rest is just leverage changes.
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Slimy38
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| posted on 29/8/23 at 03:42 PM |
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I'm trying to think about this without any frame of reference other than some misspent biking years in my youth, so I apologise if I am just
rambling or talking nonsense...
I can understand you've gone for full mechanical advantage, in order to give the biggest pedal distance and effectively 'widen' the
biting point. But with full mechanical advantage there wouldn't be any physical feedback on the clutch, the only resistance you would feel would
probably be the return spring. I think I would agree with nick, what happened with the other positions? Would a smaller advantage be better, even
though it sounds backwards?
As an alternative, from my biking days I remember a good update was to change the clutch pack springs. They were obviously much harder on my fingers,
but it did give more feedback on what the clutch was doing. I went for EBC heavy duty ones, I think they were maybe a tenner? They had been originally
purchased to save my second gear (Yamaha Thundercat + cackhanded shifts = no second gear), but I preferred the way they felt as well. A set of those
might be good to offset the weight of your plates of meat.
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adithorp
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| posted on 29/8/23 at 04:51 PM |
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You want the cable where it is (or even further over if you can engineer it) to give max advantage/least cable movement. Go the other way and
you'll get a very binary clutch (on-off and nothing in between).
If that's still not enough you can extend the arm on the clutch end. Yes, it'll be very light but that's the trade off you make.
Have you got heavy duty spring set? Barnet are best but stick to standard Yamaha steels+frictions.
Have you driven a bec before? Even with the best set-up they're easy to stall until you get used to it.
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roadrunner
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| posted on 29/8/23 at 07:09 PM |
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The close to the pedal pivot point you go the more progressive the clutch bite will be.
I run a zx10r and have the clutch cable as close to the pivot point I can get it.
Uprated springs will also help
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woodsy144
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| posted on 29/8/23 at 10:29 PM |
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To answer the questions.
- I have not tried other positions
- I have installed heavier springs in the clutch
- Problem I am currently experiencing is lack of feedback to understand bite point, lack of feedback makes it difficult to modulate
- First time driving a BEC, so I am not 100% use to it
I was after some feedback before I went down the rabbit hole of changing everything.
I have made a longer clutch arm for the engine, which is 'somewhat' easy to install (even though some moron "me" but a muffler in
the way), so I might try that first and see how that goes.
And yes may try going the other way to see if I make it heavier if I can feel bite point.
One option I am thinking about is a hand clutch. We use to run a setup on our Uni FSAE car similar to the following. Which worked quite well and
allows some clutch engagement when changing gears.
Coming to and from a stop may be a pain.
https://fsae.uta.edu/media/news/2020/03/time-for-testing/
https://rc.library.uta.edu/uta-ir/bitstream/handle/10106/26845/CHALMELA-THESIS-2017.pdf?sequence=1&isAllowed=y
Issue being having a hand off the wheel when taking off, which isnt ideal.
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coyoteboy
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| posted on 29/8/23 at 11:15 PM |
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So the feedback only comes from the spring force at the clutch end, and I don't think they're designed to have any feedback in particular
(unlike a car clutch where the spring plate has a natural non-linear spring rate). So you'll have to make it. Either make a non-linear cam that
is adjusted to give something to differentiate, or add a helper spring to either assist or fight the pedal travel at the critical point. Just
adjusting the leverage ratio isn't going to change the feel fundamentally other than to change the effective linear spring constant.
[Edited on 29/8/2023 by coyoteboy]
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Mr Whippy
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| posted on 30/8/23 at 06:16 AM |
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You'll just get use to it, you should try driving my car.
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jelly head
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| posted on 30/8/23 at 09:15 AM |
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i had a similar set up - 07 R1, new clutch and uprated springs, used to stall all the time too due to lack of feel. Best i could manage was by
extending the clutch arm / bracket on the engine to give it more throw and move the clutch cable mount on the pedal closer to the pivot, then add
additional springs to the clutch pedal to try and add a bit of weight. While it did improve pulling away, the light, feel-less clutch, combined with
the lack of low down torque spoilt the experience and i never really got on with it.
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ReMan
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| posted on 31/8/23 at 10:54 AM |
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As bike rider and having had the cable clutch-Fire blade engine in the kit for 16 years with heavy springs not for feel, but just to update the clutch
and minimise the chance of slippage and with a very rudimentary MK pedal, not the fancy spangler you have.
I think that you may be looking for the impossible. You will never modulate with the finesse of a hand clutch and standard spring, with a pedal, size
9s and heavy springs.
However, you will get used to it as you get braver with your use of revs and practice. It can take some time!
A couple of things though to try, obviously all your pivots need to be clean and lubed. The ones on the alloy cranks are not pivoting on bolt thread
are they?
You really need a good quality cable, ideally a lined one if it is not and you need to make sure you have the most shallow bends possible, even if it
means a longer cable and finding a different route, but also make absolutely sure you don't dial ANY twist into the inner cable (sorry if
teaching to suck eggs on this one, but its easy done).
HTH
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woodsy144
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| posted on 5/9/23 at 11:03 PM |
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Thanks for the feedback.
One thing I have noticed, is the 'take up point' is right at the top of the pedal stroke, which I feel is not helping me - just not natural
feeling being so close to the end of pedal stroke.
Ive increased the slack in the cable and moved the take up point further down the pedal stroke, about half to 3/4 qrts. Ill see how that goes.
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