Blip or Not?

[MightyDuc Racing]

Sell some sliders and get an electric shift cut-out! ;D

[Nate R]

LOL Mighty!

Harley and Japanese bikes are different overall, but trannies are built on the same principle, with small variations.

I'd rather replace a clutch than dogs or forks. I talked to the engineer again, and while what he said still stands, and from the data he's seen, it will make a noticeable difference in tranny life, he thinks that it's not gonna be as big a deal in racing. (Last time we talked about this, it was in reference to street riding only) There's harder shifts going on when racing, but less of them overall. So, maybe I'll start going clutchless.

So, the best way to do it is like a reverse blip, with shifting while I'm rolling off a bit?

Seems like GP shifting would make that easier to do in synch, too.

Hmm, maybe I'll start doing both. I should be able to adapt pretty quick.

You

[MightyDuc Racing]

Exactly...just a quick close of the throttle as you shift.  It's a piece of cake and should be natural feeling to you almost instantly after you start doing it.

[lfg929]

I blip, but it sounds like the tracks I run don't have such tight turns coming down from high speeds. I am more concerned about over-revving the motor than anything else (I like using the motor to help slow down). I checked during practice at Mid-Ohio just to see what my revs where when downshifting and they came in at around 9K after the shift (which is good).

As for using the clutch on upshifts, I always use the clutch for everything. I don't let of the gas though (quick half pull on the clutch lever, shift into the next gear, fully release lever). I honestly don't see how that can cause any more loss of time vs letting off the gas long enough to shift. Maybe it does, but I would rather make the time up elsewhere and replace my clutch plates rather than have to worry about replacing a couple of gears because I wore out the dog legs. Replacing clutch plates=easy, gears=not so easy (homie doesn't like splitting cases).

[Super Dave]

I'd rather replace a clutch than dogs or forks. I talked to the engineer again, and while what he said still stands, and from the data he's seen, it will make a noticeable difference in tranny life, he thinks that it's not gonna be as big a deal in racing. (Last time we talked about this, it was in reference to street riding only) There's harder shifts going on when racing, but less of them overall. So, maybe I'll start going clutchless.

So, the best way to do it is like a reverse blip, with shifting while I'm rolling off a bit?

Seems like GP shifting would make that easier to do in synch, too.

Hmm, maybe I'll start doing both. I should be able to adapt pretty quick.

You

Ok, stop using the clutch on up shifts.  Do I have to say this again.

How about this....  Heat and debris.  You're accelerating hard and you up shift using the clutch, the clutch is hooked up, now it is not, and it has to hook up again.  Lots of heat and clutch material gets worn.  

The unloading of the chassis is huge.

MC transmissions are very basic.  All you need to do is unload the trans and shift; it's very basic.  If you wear out a trans doing this, there are other issues.

And we're racing here!  This isn't street riding, but even then, when I do take the chance of street riding, I seldom upshift using the clutch.  It's seemless.

As for a guy making noise downshifting an 03 ZX6R...sounds like a personal problem:  a ZX6RR has a slipper clutch...no blipping needed.  ZX6R (a 636cc bike) would need a blip potentially to stop the reverse loading.  Sounds like the guy is pulling in the clutch and holding it in and trying to do more than one down shift or he's letting the motor rev's drop a lot more than the countershaft speed.

[lil_thorny]

I blip, therefore I race. just be careful not to over rev on the way down. rev limitation occurs on the way up. Unfortunately my gsxr 600 has felt 16000 rpms
a time or two while doing this. not good for the valve train. lucky for me I have a bullet proof motor built
by Greg Moon @ Moon Super Cycle. ;D
I'm such a hoo er
lil thorny.
SD,
you make me hot!!!!!!!!! :-* :-*

[motomadness]

Nate,

 I can tell you that using the clutch for upshift has worn out my clutch plates.  The effect on the trans feels almost seemless.  It's not a clunky action like on a down shift because the gearing is such that the trans output is synched with the vehicle speed without any other action.  In a downshift mode, you have to slow the vehicle, then try to synch the transmission and vehicle speeds while balancing clutch pressure, brake and throttle.

Try this:
- draw a sine wave (at least one-quarter period)
- draw another sine wave on top of it, but this time phase shift a few degrees and increase the amplitude

These two waves will be your increase vehicle speed with each increasing gear change.  Now pretend like you are accelerating up the first curve.  Before you get to the top, you think about jumping to the next higher curve.  Since you are continuing along this upward trajectory, you figure it's easy.  I'm already going up, so I can just keep going.  UPSHIFT

Now say before you reached the top of the first curve you decided to decelerate and downshift.  The two curves would shift in phase and amplitude, but the slope would be negative  and larger than during the upshift.  During the deceleration (imagine you are falling at terminal velocity) you see the next lower hill (lower gear) and it is rocky and jagged (does synch easily this way).  If you don't blip the throttle, nothing is going to slow your decent before impact (nothing to improve the speed synchronization).  Blip = parachute. DOWNSHIFT

[TZ_Boy]

  Your'e not just wearing your clutch plates out, you are beating grooves into your clutch basket which isn't cheap.  The Harley engineer is incorrect and doesn't understand how a constant mesh transmission work's.  When you shift with out the clutch and feel how seamless it is compared to using the clutch which is abrubt, you will realize which procedure is wearing out your trans,clutch plates, clutch basket, chain, and sprocket's more.

[khanson]

I don't blip at all.  You have to practice at either one to get it right.  For me....I found that I could focus on braking more by not blipping and being smooth with the clutch when I let it out.  Even when I raced Ducati's I could be leaned over on my knee and grab a downshift without blipping and not upset the chassis.

It's all in what you get used to and are comfortable with.

[Nate R]

TZ-Boy, his opinion was based on test data he has seen. I'm pretty sure he knows how a constant mesh tranny works since that's what he works on for a living. He's spent the last year or so working on fixing problems with some 04 trannys, and making the trannys quieter for the japan models. He knows VERY well how the tranny and clutch work, and what wears out and why.

We were speaking more of what would wear the TRANNY only more, not the rest of the drivetrain. Sure it's more clutch wear, etc, but clutch plates are cheaper and MUCH easier to replace than dogs. That was my issue.  He answered that only, because that's only what I asked.

[TZ_Boy]

  It's not just the plates it also the basket which is more expensive than a gear.  Try and shift with out the clutch and make up your own mind with how it feels and sounds to you.

[Nate R]

Yeah, gears are cheap, but you have to split the cases to get to them. (I could be wrong on this. I myself am not an expert on trannys)

My conclusion is already made, I think. I'm going to clutchless. It may wear on the dogs more, but it won't make much of a difference on the track, as I'd probably be rebuilding the motor by the time that happened anyway.