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Author Topic: query about clutch mechanism.  (Read 480 times)

neil

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query about clutch mechanism.
« on: July 19, 2013, 03:39:40 PM »
We all have to live with the R. E. clutch which for generations relies on the long rod, ball bearing, short rod to lift the clutch pack to disengage enough to accommodate gear changes. But, - - - It isn't very good at lifting and holding the clutch pack at a stop waiting for a traffic light, or awaiting traffic to clear before entering an intersection. If I pull the lever in and hold it any length of time the clutch pack generates friction and heats up. Trying to shift or find neutral after that is a real pain. Seems to me there must be a better solution than down shifting every time you need to stop to avoid this problem.

I notice on my Honda that the clutch cable ends at a revolving  shaft that activates the clutch inside the primary, engine case, more effectively than our push rod mechanism. My question is, has Tom, aka ace, chumma or cmw tried to adopt this clutch activation method to pull the clutch pack apart when the clutch is pulled in on the handle bar rather than try to shove it apart with the rod and ball bearing application we currently have to use.

Can the outer primary accommodate it?, or would this type of adaptation have to be pieced on to the outside of the primary? The bikes from other sources seems to have solved this engineering problem and they work far better than the method we are using.

Anybody care to respond.

Neil and Buzzy the Bullet

Chasfield

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Re: query about clutch mechanism.
« Reply #1 on: July 19, 2013, 04:25:38 PM »
The amount of lift is marginal on the Bullet clutch mech. I am not sure another style of lift actuator would necessarily make a lot of difference.

Warped plates are the biggest stealer of that limited clutch lift. I have found two types of warping: flat plates that have some twist; and the two unlined, dished plates having conical contact surfaces, like the rim of a soup plate. Getting these defects out of the pack makes a colossal difference to clutch drag levels.

The other bogey is the compliant outer gearbox cover that bulges out under clutch lift loads, squandering lift. Hitchcocks do a little stiffener kit for that. I have it fitted and it did help a bit.

I have just discovered (written up in a recent thread) that the thrust "bearing" that helps hold the clutch basket up when the clutch is pulled in is actually made out of friction material that contributes to clutch lock up when the clutch is released. This must ruin the purity of clutch release and make some of that heat.

2001 500 Bullet Deluxe

ace.cafe

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Re: query about clutch mechanism.
« Reply #2 on: July 19, 2013, 04:59:57 PM »
It is possible to use a different clutch.
We often use the Bob Newby racing clutch with the Fireball builds. It's expensive, but works well.

As Chasfield states, the plate stack is a major culprit in all this, but the springs have a very short travel before they bind up, also.

Making a new type of clutch release that goes thru the outer primary is a real can of worms. You will have issues with the outer primary flexing and cracking, and potentially also leaking. And you will have to engineer and build an entirely new clutch for the bike too.

You can help to reduce the heat in the clutch actuating rod by substituting a ceramic ball bearing into the mechanism in place of the steel ball bearing. This is a very easy mod, and we do it to all Fireballs now. It greatly reduces the friction and heat from that location, and completely prevents the friction-welding of the ball to the release rods.

The old 4-speed has a neutral lever which you can use to avoid downshifting thru the gears when you come to a stop. The 5-speed does not have this.
I personally always downshift as I come to a stop, so I'm always in first or second gear when I roll up to that red light. Easy as pie to put it into neutral at that point, assuming you have kept the clutch in good working order.

Contrary to what the MSF people like to say, I recommend to NEVER EVER hold the clutch in at a stop light or other intersection unless if is just for a few seconds for a quick stop and go.
It is much more likely that the clutch cable could snap, propelling you into the intersection, than it is for a random rear-end collision to occur. In my lifetime of more than a million miles on two wheels, I have NEVER been hit from behind where holding in the clutch could have had any benefit, but I have had many clutch cables snap.
« Last Edit: July 19, 2013, 05:04:22 PM by ace.cafe »
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02Electra

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Re: query about clutch mechanism.
« Reply #3 on: July 19, 2013, 05:51:20 PM »
+1 to Tom above.

I'll suggest this - Whatever gearbox/bike you have, try and inculcate a habit to be in neutral when at the lights and also to downshift gradually while reaching the stopping point rather than trying to shed all gears while standing.

I have a 4 speed so it's easier to get it in neutral but I don't remember ever doing a 4th to neutral jump with it. It is mostly from 2nd to neutral as I keep downshifting with slowing speed. If you have a 4 speed it's real easy to downshift with the neutral finder too.

Cheers.
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India

ROVERMAN

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Re: query about clutch mechanism.
« Reply #4 on: July 20, 2013, 03:13:35 PM »
I get many stares from motorists as i reach down and lift up for neutral without  taking my gaze from the road. I have a left shift 4 spd. The clutch is pretty shabby but treat it nice and it does the job. 8) 8) 8)
Robert & REnfield.

neil

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Re: query about clutch mechanism.
« Reply #5 on: July 20, 2013, 06:27:14 PM »
Thanks for the replies, I too downshift thru the gears as I approach stop locations. Sometimes things "pop-up suddenly" and doing the down shifting isn't always possible. My bike is a left shift 5 speed so I have never had the luxury of a neutral finder. I have ordered and received a new short rod with the push knob equipped with tiny roller bearings. I don't know if that will make a difference but I'm going to try it.

I've worked on the stack in the past trying to get an even lift when the clutch handle is activated. Not always as smooth and even as I would like. I've also changed the springs and shimmed the clutch holding screws with even thickness washers to change, shorten the distance the basket has to move before a clean separation occurs. As far as I can tell all the clutch metal plates are flat and not warped. It seems to me pulling the plates apart would yield a cleaner better lift than shoving them apart with a rod from the opposite side of the bike. It may be impossible with the current configuration of the bike but I still think pulling would be better than pushing. Meanwhile I'll try to adjust my current arrangement to perform better while every other biker I see is able to down shift and hold in their lever while waiting for the green light. I don't mind downshifting because every one has to in order to get started again. It's just the few times that Buzzy gets a little cantankerous and jumps from first  to second, bypassing neutral and then when I try to tap down to neutral, he jumps passed neutral again and ends up in first.  I've been known to avoid this frustrating jig by shutting the bike off putting it into neutral and then kicking it into life again for a fresh start. If their is traffic behind me they don't seem to enjoy the delay I'm creating.

Neil and Buzzy the Bullet

ps. when I install the new short rod, I hope it will make things better. I'll post about it later.