| Author | Message | ||
     Parrick |
I need some comparative impressions. The clutch is a little stiff. Not horrible but stiff. I don't feel a big difference between bike running & engine off. If I start with engine off, pull the clutch in about half, pull in & out a bit and then start the engine while I'm oscillating it like that I don't feel a big difference once the engine is running. I was just wondering if the vacuum assist should be significantly noticeable? | ||
| Badlionsfan |
The vacuum assist is for the slipper action of the clutch on high rpm down shifts. It has nothing to do with the pull of the lever. | ||
| Hootowl |
The clutch doesn't have a vacuum assist at the lever. It has a vacuum assisted slipper for when you downshift and dump the clutch. | ||
| Hootowl |
Bah, beat me by seconds... | ||
| Fresnobuell |
I do feel a difference on the clutch pull when the bike is running versus off. I believe the vacuum helps with clutch pull as well as the downshifting mentioned above. | ||
| Parrick |
Aww crap. You're all so right. I even kinda knew that but sometimes I get confused between what I read in tech literature and what I saw in a talkgroup post. Crap I'm embarrassed. Brain fart. Thanks for straightening me out! | ||
| Ron_luning |
From Buell's website: "6-SPEED TRANSMISSION WITH HVA: This 6-speed, close ratio transmission features smooth and precise action. The Hydraulic Vacuum Assist (HVA) Slipper-Action clutch eases clutch pull and limits back-torque during hard downshifts." The vacuum assist does reduce clutch lever effort. It does so because the vacuum is able to make the clutch slip by pulling on the diaphragm that in turn takes a little tension off the clutch pack. Try this: instead of feeling the clutch lever effort with the engine off vs. engine idling, try the clutch pull at engine idling vs. pulling in the clutch after closing the throttle at high rpm (while riding of course). There is much more vacuum drawn at high rpm and a closed throttle; that should allow you to notice the difference. Maybe it's not as useful as they advertise, but it does have an affect. | ||
| Jdugger |
If you will roll down a steep hill at speed and compare the lever action of the clutch there you will notice the lighter action. It's pretty significant. The clutch uses vacuum pressure from the throttle bodies to (in theory) help disengage the clutch during hard downshifting. But, don't think, even for a second, it's a slipper clutch because I can assure you it very much is not unless you are very heavy. If you downshift hard, you will skip the rear tire. It's not like a Ducati slipper when you can adjust the action and almost get it to slip like a freewheel. |
