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  Topic Review (Newest First)
11-08-2019 10:25 AM
Mastercore Epilogue
Since my last post I have been away for an off road tour in Sardinia, Italy.
The trip took me roughly down the centre of the island with over 50% off road, some of it rather difficult. (I would not recommend doing it alone on a large bike)
My wrist was still not 100% and I used my ad hock clutch lightener throughout. But I was loosening it during the ride as my wrist got stronger (the exercise actually accelerated my recovery ;-)

Even though the wrist is still injured and I am not at 100% recovery, I can ride without pain.

Findings:
The clutch is fine after the tour. Occasionally, during riding days, I would feel the clutch case to see if it was overly hot. There was not much more I could do to monitor the situation.
I spoke to my mechanic before the tour about the issue that were brought up by @ProCycle , his opinion is that this part is nothing to worry about. It will outlive the clutch even with this mod, and can be inspected each time the clutch is replaced.
The more I use this mod (the more intrusive I set it) the shorter the life of the clutch will be, resulting in more regular inspections of the release bearing.
He told me a new clutch is only about €100 and pretty easy to replace, so save your wrist and don't worry about the clutch wear.

Conclusion:
For a mod that is none destructive (no permanent parts of the bike have to permanently modified to install this mod); is easy to install and de-install on the road side; is adjustable to quite a fine degree (counting the number of lock nut turns); and very compact and quite light to carry along on a tour, it is a no brainer for anyone that has troubles with the left wrist and the clutch.
Off road riding requires a LOT more work with the clutch hand. On a tough off road days, many riders will feel the left forearm fatigue I think. This mod will definitely help to lighten the load on the wrist and allow you to enjoy the ride much more.
I can imagine that for bikes with no traction control, this mod could be used to not only lighten the clutch but to also dial in a minimum level of fixed clutch slip on really gnarly terrain. Since it is so easy to adjust, install and remove, I could image tweaking it through a riding day to suit.
Would be cool to even have some handlebar accessible adjuster where its effect could be dialed in on the fly!
09-04-2019 12:00 PM
Mastercore Had a chat with the garage from whom I bought my bike.
Explained the setup and he checked it out himself.
He tells me that there is a roller bearing between the actuator arm and the pressure plate.
Eventhough he admits and any added pressure will obviously add to wear, he feels that in the AT it will be negligable.
Also he told me that the clutch pack is only ~CHF170 and is not a headache to change out.
So when put against the wrist injury, its nothing.
09-01-2019 01:57 PM
Robert Detjen Start with a clutch lever with an adjustable pivot point. If you can handle a longer pull, then it's all you should need.



09-01-2019 10:31 AM
Mastercore
Quote:
Originally Posted by DRandAT View Post
Have you considered a Rekluse Cutch?


Sent from my iPad using Tapatalk
I know there are some after market solutions about clutches but all seem to be solutions to a permanent problem.
Mine is only while my wrist heals.

Like I said in my previous post, before my wrist injury, this was not even a subject for me. I was happy with the clutch weight. But while I am healing from this injury, I want to still make use of my bike as a commuter (my normal use apart from adventure) without hampering my recovery.

I rode a GS800 for 2 days very technical offroad last year (now wrist injury) and I found the clutch was too heavy for me. I had a burning fore arm by the end of the first day and the second was agony. I would definitely use some hydraulic or other after market solution on a bike like that.

BTW,
From what I could read, the rekluse clutch seems to be a different clutch pack with more layers. Am I understand this properly?
If so, how does this exactly lighten the clutch I wonder?

Thanks for your suggestion
09-01-2019 05:36 AM
DRandAT Have you considered a Rekluse Cutch?


Sent from my iPad using Tapatalk
08-31-2019 05:11 AM
Mastercore Thanks @ProCycle
I have been looking at the workshop manual to get a better idea of the mechanics of this connection.
I understand pretty well what part you are talking about. it is the part that connects the rotating pressure plate to the stationary "actuator arm" (the best words I could think of)
The manual is a little light on what exactly is going on here because it concentrates on assembly and disassembly.

My intended use of this mod was to increase the assisting pressure of the spring mainly when I am off-road.
I imagined from the start that this mod would increase the wear of some parts inside, but I assumed the cost was bearable considering it meant I could keep riding and I not impede my recovery.



Has anyone out there got good pics of a clutch change operation on the AT. In particular, how and what is actually in contact with the clutch pressure plate to activate it?
08-30-2019 02:04 PM
ProCycle
Quote:
Originally Posted by Mastercore View Post
Interesting, will look into this.
Thanks for your input
Yeah, release bearings are sized for momentary intermittent duty. Spinning with pressure on it for long periods would very likely overwork it.
Usually referred to as a throwout bearing it's a pretty common failure in the automotive world. Folks get a bad habit of sitting in traffic in gear with the clutch pedal depressed or driving around with their foot on the pedal and that toasts the bearing.

I looked at the parts breakdown and didn't actually see a separate bearing. It may be that Honda only sells it integral with the pressure plate.

I like experiment you are doing but I would strongly consider traveling with spares and tools to replace the release bearing if it fails far from home.
08-30-2019 01:08 PM
Mastercore Interesting, will look into this.
Thanks for your input
08-30-2019 01:03 PM
ProCycle I'd be very concerned with severely shortening the life of whatever the AT uses as a release bearing.
08-30-2019 04:23 AM
Mastercore
Quote:
Originally Posted by RayCollington View Post
I would be concerned what effect the constant spring pressure might have on the clutch life and if any high torque situations could result in slippage.
I am with you on this. It was the reason I built this prototype the way I did.
There is a 6mm threaded rod connecting the spring. I can count the tightening nut turns to gauge the relative tension of the assisting spring.
I tweaked the design so that I can tighten it till it opens the clutch, or loosen it till it has no tension at all on the system.



This is what my testing of different setting has yielded:

- At low RPM I find that the adding more tension to the spring is tolerated. I cannot notice any slippage even if I jerk the throttle open and closed in first and second gears. The reactions between accelerating and decelerating is sharp and crisp. It is the same as with no spring tension at all.
At a functional tension for this low RPM range, the clutch is significantly lighter than stock. My guess is >50% lighter.

I played the spring tension all the way till I could feel the slip when doing this. The clutch is feathery light and I could play it even with my pinky. But this is a useless setting because at any higher speed, there is significant slip.

- At the other end of the spectrum, I can make the clutch slip even at relative low tension setting. This would be in an overtaking case. Say 80kph (45mph) and knocking it back to 5th and opening up to overtake. In 5th it still feels OK, but in the upchange back to 6th on an open throttle, there is a second or so of slip till the bike catches up.
I guess this is due to the higher HP and torque at the higher RPMs. (see image)

Because of the way this prototype is setup, I can easily adjust with an 8mm wrench.

Current conclusions:
- I have no idea yet on the effect this is having on longevity of the clutch, but I am sure it is wearing it out faster than without the mod. (obvious)
- If I detect no clutch slip, then it does not necessarily mean there is no slipping, but I am assuming it to be minimal and probably nothing to worry about.
- I have yet to do a temp test of the clutch cover, aside from using my hand which is not very scientific. At least it is not burning the skin off!
- I am also working with the assumption that motorcycle clutches are not overly difficult to replace and not very expensive.
- I am wondering about shortening the spring and bridging the gap with a fixed section to magnify the spring effect and see how it changes the behaviour.
- Using a compression spring setup may yield better results, but would require a different setup all together. Maybe if I am bored one day.
- I have used it with a pillion (a realistic simulation of a packed bike I'd say). There was a difference but it was not as large as I imagined. That surprised me.

How I can see it being used:
- I would imagine that dropping the tension right off for highway or mainly tarmac riding
- Rise the tension for off-road conditions. Especially long days off-road where the wrist may get tired and painful.



I will be doing an off-road tour around Sardinia, Italy in about a month so will have a good chance to test.
This is the real test for me will be the off-road, because road use is not the problem for me. The wrist is slowly getting better, but it is the 8h off-road riding, day after day, that will really be the test of this device.


I am a furniture designer and I can imagine a fully developed product. It would be a simple bolt on thing, which even a novice mech could install. It would be adjustable from zero to full slipping, and could be a useful add on for cable clutched bike that are a bit heavy on clutch tension (BMW GS800 for example), or female riders who find the clutch work a bit much for their left forearms.

n.b. I done some off-road tours with the africa before my injury, and did not even think of this idea.
This innovation is born basically from my ill timed injury i.e. right at the start of the riding season here in Europe.
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