Lock up clutch... NooB?

[81gs1100]

Ok, I have been thinking of running a lock up clutch this year, I have been too unconsistant cutting lights trying to hand clutch while keeping it together.

I have been reading that with a lock up you can set it up so you can throw away the clutch off the line at WOT and can set it to slip enough to keep the RPMS up and not wheelie. Which is great, but I have some concerns;

Ok, with a lock up, there is an RPM that once past you will lose the ability to use the clutch lever. ( too hard, locked up) Where is this RPM, 4000, 6000, higher? Thinking during the burnout, if the RPMs get too high to disengage the clutch, what happens? I understand you have to let the RPMs come back easing off the gas, but I done that before, hot slicks grab like a bitch shooting the object its attatched to out from under your butt.

During launch, while holding in the clutch, you have the launch RPM set at 7000 RPM, the lights come down you roll on the gas, will it work like a slider and engage the clutch as the lever pulls out of your hand? Or as long as you have the lever in the clutch won't lock up?

If set soft enough could you let up the lever and hold the bike with the front brake like a slider kinda?

I have an 81 GS1100, raked a bit, extended arm, 5" slick, and will have my air shifter shortly. Original plan was to get an adjustable air clutch control to control the clutch release to soften launches. The lockup from what I have been learning would be an easier and more reliable option.

So, let me hear all of your opinions as well as burnout to launch walk-throughs.

 

[gearhead13]

The lock up arms are mounted on the inner hub which is connected to the rear wheel. So, it locks up as rear wheel speed increases, how fast depends on spring weight and arm weight.
Drop the clutch off the line and all the clamping force you see is spring weight, then as speed increases, the arms start to lock it up.
You tune your launch with different weight springs and more/less weight on the arms.
Slider weights are on the outer basket, locks up with more rpm.

 

[81gs1100]

The lock up arms are mounted on the inner hub which is connected to the rear wheel. So, it locks up as rear wheel speed increases, how fast depends on spring weight and arm weight.
Drop the clutch off the line and all the clamping force you see is spring weight, then as speed increases, the arms start to lock it up.
You tune your launch with different weight springs and more/less weight on the arms.
Slider weights are on the outer basket, locks up with more rpm.

So that explans the launch, I should be able to rev to any RPM and the clutch wont grab because the rear wheel is not turning, so no locking pressure?

Ok, so the burn out, as rear wheel speed increases, what wheel speed would be safe for more baseline lockup clutch setups so that the clutch can be disengaged with the lever?

 

[gearhead13]

I have never noticed any problem pulling in the clutch at any speed. Top end of 3rd or 4th. Same as I have heard others say about the subject. Much higher than your wheel speed during a burnout I would think.

 

[Guest]

I ran a lock up for years & never had any issues not being able to pull in the clutch lever.

 

[madjack57754]

You are asking a number of questions about different but related systems, so I'll try to give my take on each of them.
On the funnybike, I use a lockup and an air release clutch lever along with a full auto 3 speed trans. The air is regulated by an adjustable needle valve on the release cylinder to feed the clutch out when the launch button is let fly and to control wheel spin on marginal tracks.This is used with a timer when leaving on a full tree where I react on the top amber bulb. With a pro tree, the timer is shut off and I just let fly. The adjustable valve is actually a hydraulic flow control valve that is adjusted like a micrometer. You kind of have the wrong idea about a lock up on launch. The lock up just rides along until your rpm allows the weights to create force on the clutch hat, pressing down to overcome the release springs, mechanically locking the inner and outer hubs. When the rpm dropes below engagement the arms disengage and clutch operation is normal.
Your next alternative is a slider clutch that has no release lever and operates strictly on rpm, using arms and weights to engage and lock up the clutch. The down side of the slider is you need to be towed back after a pass. That and they are kind of fragile. Burnouts are tricky and dry hops will kill the clutches and spring towers, and that gets expensive in a hurry. Ask anyone who runs one and you will get lots of stories of burned up clutch packs and spendy broken parts. Don't get me wrong on the slider, I run one on my bracket bike and once I learned what not to do, My consistancy on launch control went way up, while my reaction times went way down, and are now adjustable in the clutch and dial box, not in my head. It was an expensive lesson that took a whole summer to figure out, and there are times when I still get lost in my adjustments.