Never asked if this is normal and I honestly can't tell you if this happens every time since I hardly ever take off with mid range to high revs. So, say I want to take off a little fast from a dead stop. Bring the rpms to say around 5k and I start to "ease" off the clutch and the bike just jerks into gear. I'm not dumping the clutch and it usually happens when the clutch lever is barely let go.
I'm planning on going to the strip this saturday for giggles since I've never gone. I'd like to take a "normal" take off as you would do when drag racing, but I dont want my bike to be a bucking bronco.
[image: View Post]rangerscott69, on 28 October 2010 - 10:23 PM, said:
Never asked if this is normal and I honestly can't tell you if this happens every time since I hardly ever take off with mid range to high revs. So, say I want to take off a little fast from a dead stop. Bring the rpms to say around 5k and I start to "ease" off the clutch and the bike just jerks into gear. I'm not dumping the clutch and it usually happens when the clutch lever is barely let go.
I'm planning on going to the strip this saturday for giggles since I've never gone. I'd like to take a "normal" take off as you would do when drag racing, but I dont want my bike to be a bucking bronco.
Mine has done that a couple of times too, especially when cold. Hasn't done it in a while though.
You know I was about to say that it's never happened to me.
But now that I think about it, yeah I do hear some sort of clunking on hefty launches.
I don't feel it in the box though, which at the time lead me to believe it may have been the cush rubbers out back.
Hasn't happened in a while... should look into that.
As for drags... well, moreso harder launches.
For me it comes from feel, and more importantly being smooth with the clutch.
In standard gearing, droppin the clutch too quickly really hurts the V4.
Adding revs just hurts the clutch.
But there is a nice balance in between somewhere.
My 5th gen has done it about half a dozen times over the past four years....It seems to onlyoccur when it is hot and I restart leaving a gas up or lunch and need to accelerate briskly but smoothly into traffic.
I think it may be clutch wear from the previous owner but havent confirmed yet...
My experience is the VFR ( 5th and 6th gen, can't speak to the others) just has poor clutch "feel" - very difficult to get much feedback through the lever, and this really shows when you're trying to launch it hard. it either grabs and jumps or slips. That said, I would make sure the system is working as best as it possibly can. Fresh fluid and a thorough bleed. If you really wanted it as good as it could be, a fresh rebuild on the slave and master cylinders would ensure nothing was sticking. Then for the ultimate - a stainless clutch line. I've seen clutches go "grabby" as described, but that usually is the result of a broken or torn fiber plate(s) and I would bet that's not your problem.
A friend an I take our VFRs to the track once or twice a year for fun (a 2000 and a 2002), and they are just hard to launch consistently/smoothly - and I've been riding drag bikes for what seems like all my life. Try setting your initial launch rpm at about 6k and on the last yellow roll it open while quickly easing out the clutch. With the VFR you should get no wheel spin - (a burn-out is unnecessary). After a few trys you should be able to modulate the throttle and clutch together to float the front end out. We typically get mid to upper 11s at around 117mph. Good luck and have fun! :fing02:
[image: View Post]mechdziner714, on 29 October 2010 - 10:47 AM, said:
This is why you dont see hydraulic clutches on drag bikes.
mine too. i cant bring the revs up first and then ease the clutch out. if the revs are above 3 or four grand the clutch turns into a on/off switch.
the only way i can launch the bike hard is to intially release the clutch at about 2-3 grand and as soon as i fell it engaging, roll on the gas and ease out of the clutch.
[image: View Post]rangerscott69, on 28 October 2010 - 10:23 PM, said:
Bring the rpms to say around 5k and I start to "ease" off the clutch and the bike just jerks into gear. I'm not dumping the clutch and it usually happens when the clutch lever is barely let go..............I dont want my bike to be a bucking bronco.
My 2000 does the exact same thing, hot, cold, using Mobile One, Valvoline MC oil, or cheap Walmart stuff. It has nothing to do with temperature or oil, but is instead some form of clutch chatter. Anything over about 4K and the bucking bronco rears its ugly head! Yeah, it really surprised me when I attempted my first "drag race style" start, and yes, this has been mentioned before a few years ago here on VFRD. So.....it's normal, unfortunately.
[image: View Post]CandyRedRC46, on 29 October 2010 - 11:22 AM, said:
The only way i can launch the bike hard is to intially release the clutch at about 2-3 grand and as soon as i fell it engaging, roll on the gas and ease out of the clutch.
[image: View Post]mechdziner714, on 29 October 2010 - 10:47 AM, said:
This is why you dont see hydraulic clutches on drag bikes.
Not quite as true as 5 or 6 years ago. Now there are supposed to be some pretty good, drag race specific, hydraulic aftermarket clutch systems - not that is matters for our VFRs.
I still think the biggest problem folks are experiencing here is lack of practice. The clutch is touchy, granted, but most of us don't try to really "launch" our bikes often enough to get the feel for it. I'm betting that most members could get good launches within ten tries. Crawl up on the tank, spin it up (way higher than 2-3k) and slip it out. Chances are good you are going to make it "buck" the first few times, but acceptable, floating launches will come - even with our vague, hydraulic clutches.
[image: View Post]rangerscott69, on 28 October 2010 - 10:23 PM, said:
Never asked if this is normal and I honestly can't tell you if this happens every time since I hardly ever take off with mid range to high revs. So, say I want to take off a little fast from a dead stop. Bring the rpms to say around 5k and I start to "ease" off the clutch and the bike just jerks into gear. I'm not dumping the clutch and it usually happens when the clutch lever is barely let go.
I'm planning on going to the strip this saturday for giggles since I've never gone. I'd like to take a "normal" take off as you would do when drag racing, but I dont want my bike to be a bucking bronco.
It's only normal if you let it be that way...
Years ago when i was racing (against some kids, Ben Spies and Jason DiSalvo in 125GP) and practicing starts at the drag strip i found that removing the burrs from the clutch plates would do a couple of things:
1) Make for a smoother clutch release, and
2) Extend the life of the aluminum hub and basket, high $$ items, and
3) Nearly put an end or greatly reduce the amount of aluminum shards getting into the oil/engine.
Here are some pictures to illustrate:
[image: Posted Image] 08-14-10_1213.jpg
[image: Posted Image] DSCN0115.JPG
[image: Posted Image] 08-14-10_1212.jpg
[image: Posted Image] clutch_plate.jpeg
The burrs are formed during punch pressing of the plates. They don't de-burr the plates, and the burrs will cut little corn cob rows in your hub and basket. i use a file or a dremel with carbide bit to chamfer the edges. Good for what ails ya...
[image: View Post]kennybobby, on 29 October 2010 - 03:33 PM, said:
The burrs are formed during punch pressing of the plates. They don't de-burr the plates, and the burrs will cut little corn cob rows in your hub and basket. i use a file or a dremel with carbide bit to chamfer the edges. Good for what ails ya...
That makes sense - removes the chance that the metal plates will dig into the clutch basket and stick, finally letting go when the pressure plate is pressing hard enough so you get a grabby clutch. deburring lets the plates slide more free and so smooths out the clutch action.
Going down the road about 60 in 3rd, pull the clutch in, hold revs at a solid, steady 10,000. Tried easing the clutch out and got the same bucking-bronco and the wild clutch lever pulsations that "we" have from a high-rev standing start. Strange, huh?
The issue of burris grabbing (and suddenly relasing) the hub & basket may have merit, I'll agree, but I'm still trying to work out why the bucking continues instead of just once when the burrs finally let go. And as for deburring, you'll still have the corn cob rows in the hub and basket to affect plate movement, I'd think. But it seems as if there is almost a centrifugal aspect to this violent clutch chatter, or some other reason for crazy spring bounce or maybe it's just total drivetrain lash doing its thing. Reminds me of when someone first tries to drive a manual car and gets that hilarious herky-jerky from not letting the clutch slip for a fraction of a second while giving it a touch of throttle. But once a person learns that "friction point feel", they rarely herky-jerk a car again. So....why are we doing that with our VFRs?
My RC doesn't do this, BTW, and it's a hydraulic clutch.
The ER-6N was a lot better at take offs and I could do a burnout to heat the rear. Got my reaction time down to .64sec, but it's up and down with that. My fastest was 84mph @ 8.3153 sec. Slower bike, but I like to be able to take off fast.
[image: View Post]rangerscott69, on 31 October 2010 - 08:14 PM, said:
The ER-6N was a lot better at take offs and I could do a burnout to heat the rear. Got my reaction time down to .64sec, but it's up and down with that. My fastest was 84mph @ 8.3153 sec. Slower bike, but I like to be able to take off fast.
There's one thing that's been missed. Yes, the clutch basket contributes to it, as does the hydraulic clutch, but also the clutch throw rod which goes from the left side right through to the right side develops crud build up (or even wear) from chain spooge etc being turfed at it. Take off the clutch cylinder, pull the rod out, clean it, lightly grease/oil it, turn it around (it's symmetrical) and put it back in.
Won't fix the problem if the basket's badly worn, but it will help.
Had the same problem on both the VFR and the VTR I used to own.
End of thread · 26 posts recoveredWayback Machine snapshot 25 Feb 2011
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