| Author | Message | ||
     Neb25 |
Could you explain "Slipper Action" compared to a regular slipper clutch. | ||
| Anonymous |
It's not actuated by mechanical ramps in the back-torque direction, but instead by engine vaccuum on decel working on a diaphragm that takes pressure off the plates and allows them to slip. One interesting advantage compared to the mechanical ones is is that it is less likely to chatter when the wheel comes off the ground intermittantly on braking. Probably not a good enough explanation, but it will become more clear as more information comes out. | ||
| Skully |
IMHO, the vacuum actuated clutch has to be one of the most clever things on this bike. Brilliant! Keith  | ||
| Court |
>>>It's not actuated by mechanical ramps in the back-torque direction Is that the result of Mr. Buell once being fired for breaking a glass display case whilst working on a tediously complex mechanical clutch? Enquiring minds want to know. . . . we are all the products of our past.  | ||
| José_quiñones |
Same as, an evolution of, or a major improvement over the PPC (Pneumatic Power Clutch) system in the Rotax 990 motor currently used by Aprilia? | ||
| José_quiñones |
bump | ||
| Ft_bstrd |
I can't wait to try it out. Even with the modest engine braking provided by the 45* V-Twin there is significant wheel hop (then again it could be the fat guy pitching the bike forward lightening the load on the rear). I can't even imagine how bad it might be on the Helicon without a slipper clutch. Anony, is there a wear advantage vs. the ramp configuration? With a ramp configuration, there are slipper clutch actuation adjustments available. Are the same adjustments available with the vacuum assist system? How do RPMs affect the slipper action? Is it more pronounced under hard decelerations and less so under lower RPM decelerations? There are times you want the slipper action and times when you don't. In stop and go traffic, I like to use engine braking to reduce fatigue and save brakes. Less slipper action is great here. This is one of the coolest parts of the 1125R. Speed and handling are great, but braking and traction mean more in performance than anything else. I can't go fast if I can't stop fast, and I can't go fast if I can't keep the bike on the road. Bravo! | ||
| Gregtonn |
This is the way I understand it. The slipper action is provided by engine vacuum slightly relieving engagement pressure on the clutch plates to allow them to slip. There may or may not be a method of adjusting the vacuum actuation level-I don't know. However, it doesn't seem that anything other than normal clutch adjustments would be needed with such a setup. The real genius of such a setup is that wear due to slipper action would be practically nonexistent. Stop and go traffic should be no problem since vacuum levels would probably not be high enough to actuate slip. Cool! G. | ||
| Diablo1 |
The slipper clutch likely works just like the Rotax V60 unit used on the Aprilias - it's a vacuum operated diaphragm. They only provide a little slip under high vacuum conditions, which is when the throttle is closed. Open the throttle and no slip. If you were to use stronger clutch springs, you'd defeat the slipper action. Mr. Anonymous can chime in if the Buell unit is different. | ||
| Gemini |
high vacuum caused by closed throttle and high rpm will give "slipper action" all others will just give vacuum assist. it is calibrated in the hydraulic system. this might cause a bit of funny clutch lever feel for those riders who "blip" the throttle. as you begin the squeeze the lever and blip the throttle you will decrease vacuum and MIGHT be able to feel the increased effort in the lever. | ||
| Nondual |
Isn't engine-breaking a case of wearing the engine in order to 'save' the breaks? That's always seemed sorta dumb to me... | ||
| Gregtonn |
Uh, that's engine-braking and brakes. Sorry to sound like a junior high english teacher but engine-breaking looks so ugly. G. | ||
| Fresnobuell |
Engine BRAKING is probably not needed in most street riding situations, however when pushing the bike in the twisties or track, you need both the brakes and engine to help slow down the bike. Plus you know where you are in the gearbox, which is very important (wish the 1125r had a gear indicator...) | ||
| Gregtonn |
To answer your question. While engine-braking increases vacuum above the piston rings and tries to suck oil up from the crankcase, engine wear due to engine-braking is probably not measurable. G. | ||
| M1combat |
That's funny ... I find that I would rather have NO engine braking. I'd rather be able to give all braking input with my foot. It allows better control because there's less variable. With engine braking you have to tune your foot to each corner because you will come in at a different RPM. With no engine braking you tune your foot to the bike because it doesn't change. You're more consistent. Also... I don't care what gear I'm in in the least. I only want to listen to the engine and know what RPM's I'm at and how many I'll need for pulling out of the turn without needing to shift up. A gear indicator would be useless to me. I jst use my ears and I know. That way there's less thinking to distract me from my line etc... Different strokes I guess . | ||
| Fresnobuell |
M1, So the slipper clutch will be a great thing for you, no? Just thinking that with the 1125s greater RPM range, it might be easier to keep track of the gears, although the addition of the 6th gear may negate. | ||
| Metalstorm |
So does this mean that those of us who are used to "blipping" the throttle to down shift should cease to blip while riding the 1125R? | ||
| Gregtonn |
No. | ||
| M1combat |
It will be . That said... The firebolt has taught me to be careful on the brakes so I don't get wheel hop. | ||
| Ft_bstrd |
I used to use the rear brake quite a bit (holdover from dirt bike riding). What I found during aggressive riding was that because of the long travel of the front forks, the weight of the bike, and the weight of the rider, the bike would pitch forward enough to unweight the rear wheel enough that ANY rear brake application would lock the rear up. I may use the rear some when trailing or when I am not using the front brakes aggressively, but I generally don't use the rear brakes. I also didn't see much need to "blip" the throttle on down shifts. I simply used the the clutch and engine to engine brake. As I began to ride more aggressively, the engine braking began to induce severe wheel hop particularly coming into turns (see pitching forward, unweighting the rear). Blipping helps considerably. I see the slipper as allowing engine-to-rear wheel speed mismatches without requiring "blipping". By removing the "blip", the ability to downshift and engine brake more quickly is possible. Sometimes in downhill chicanes you can't "blip" like you'd like. The higher engine speed and downhill momentum causes the bike to surge into the turn before the engine braking "catches". By that time, you are too hot into the corner. Downshifting directly without having to "blip" allows the engine braking to start immediately and increase as the slipper action subsides without breaking the rear tire loose. I am really looking forward to how it works in the 1125R. I would LOVE to have one on my Uly, but I can't see paying $1,300 for the option. I can get a lot of "blips" for $1,300.  | ||
| Xb9 |
Is the slipper action adjustable? | ||
| Ft_bstrd |
I asked the same thing. It is on mechanical systems. | ||
| M1combat |
"the bike would pitch forward enough to unweight the rear wheel enough that ANY rear brake application would lock the rear up. " One thing to consider is that when you're really trying to get everything you can you can use the rear brakes JUST before the front coming into a brake zone to lower the rear of the bike. This allows you to use more front brake. Of course as you get a bit deeper into the brake zone the rear will come up and eventually off (or just about... I recommend you keep it at least skimming the ground). As you start rolling in though... you want to use the rear brakes again. It helps to level the chassis. Most people would be surprised at just how much you can use the brakes while rolling into a turn. That said... Yeah... a huge percentage of losing speed is done with the front brake for sure. The rear is very useful as well though. To get back on topic though . I think that the brake is a better and more consistent brake than an engine brake so a slipper makes great sense to me . I'm really looking forward to feeling how it works and how it affects the lever feel. | ||
| Ft_bstrd |
Using the engine allows deceleration using otherwise wasted energy. The problem is that the energy applied exceeds the traction capacity of the contact patch. The slipper compensates to allow the otherwise wasted energy to be applied without breaking traction. Yeah!!!!!! | ||
| M1combat |
I agree with that... It's just that it's more difficult to use it consistently is all . I don't just hold the clutch in until I feed power for the exit . I use engine braking but to a lesser extent than rear wheel braking. | ||
| Josh_ |
If you're using engine braking you shouldn't lock up the back wheel regardless of how hard you get on it. With the clutch out (which is required for engine braking) your little back brake most likely isn't going to stall the engine. However, most riders yank in the clutch, then stomp on the brake, which can certainly lock it up. | ||
| Dbird29 |
Sorry that doesn't make sense. If the clutch is disengaged how can it stall the engine? | ||
| Ft_bstrd |
I can definitely get it to hop with the clutch and engine braking, but you're right, I can't get it to "lock up". That only happens when I apply rear brake without clutch. You are correct, sir! | ||
| M1combat |
I was talking about hopping... Not locking . The trick is to modulate the rear brake with the clutch. It'll hop if you use too much of either. I prefer to use more rear brake than clutch (engine brake) because the engine brake modulates itself with RPM change. The rear brake only modulates with pedal pressure. The combined brake force at the rear wheel modulates as a combination of the two. The rear brake can be used more consistently. That said... You can't get much out of either one in the straight part of the brake zone except near the beginning. I generally get on the brakes (both of them) as I hit the brake marker. The rear JUST before the front. This lowers the bike instead of lowering the front and raising the rear. As the RPM's drop I "yank" in the clutch as smoothly and quickly as I can, blip and downshift. I'm a little ways into the brake zone by now and as I let out the clutch I let off a bit of the rear brake. I'm trying to keep the overall braking force of the rear wheel smooth. The rear is raising through all of this. By the end of the first downshift the rear has extended and it's just skimming the ground. I don't really use the rear brake again until I start to roll in at turn in. At that point I should be in the gear in which I would like to exit the turn but at high RPM's and still going a bit too fast to make the apex. Through roll in and the early part of the turn I'm feeding in more rear brake and releasing the front smoothly. Sorta trading one for the other. About the time I'm slowed enough and am on line for a good apex I have released the front brake and have begun releasing the rear. At that point I have a bit of rear brake left (because it levels the bike) and I start feeding in throttle and releasing the rear brake smoothly. You certainly don't want to "over"use the rear brake. That's not good. But you CERTAINLY want to use it as much as you can. It either makes the front brake more effective by lowering the rear (early brake zone), it helps with getting the bike to the right attitude for applying throttle (Near the end of the brake zone) or it helps with a smooth transition from brakes to throttle just before the apex. It's also good to use in a tightening radius turn or a double apex turn. Letting off the throttle and/or using the front brake will pitch the bike forwards. Nose low, rear high. You don't always want THAT when you DO want to slow down. In those situations the only choice you have is the rear brake. It LEVELS the bike AND slows you. This is why "I" think that a slipper is a good thing. It allows me to concentrate on just using the rear brake instead of having to modulate it against the clutch lever. It's easier and more consistent . |
