newbie which bike question.

You do realise that "only" having 5 speeds can actually be better on some
bikes ?
Yep, for reducing weight, less things to break, lower cost, and
a reduction in the risk of RSI. I can't think of _ANY_ performance benefits
(with the exception of the weight one).

No tacho, well <shrug>, ears are good !
Yep. So long as you _already_ know what you are listening for.
How many learners does that actually apply to?
In all seriousness, I still don't know _exactly_ what the sound
of the engine is at the optimum shift point, and I use my tacho a fair bit.

 

thats what the rev limiter is for

 

thats what the rev limiter is for
Well, only kinda. Bouncing it off the rev limiter means that you are
shifting too late. The rev limiter is not there to tell you when to shift,
it's there to stop you blowing the engine up.

 

nah you have it all wrong

thats for the run in period

 

You can tell a guy who only rides sports bikes Think about it this
way, would you think that putting 7 speeds into your Z would make a
performance improvement ? How about 8 or 9 ? Why do you think most of
the motoGP, race tuned bikes, only run 6 speeds ?

The ideal quantity of gears (and the gearing combinations) relates to
the shape of the torque curve - the peakier the torque band the more
gears you need - hence the Cagiva Mito 125 (and most of the 125 GP
racers until they banned it when they forced them to single cylinder as
well) had 7 gears, in the case of the 60s/70s Honda 125 & 250 multis
(and a few others I believe) they had more (Clemopaedia et al feel free
to correct me).

On the other hand the flatter the torque the less gears you need. Hence
most cruisers and engines built for torque have only 5 gears and quite
honestly on many of them 3 would have been plenty.

I converted a Jag V12 (which has a very flat torque curve) to manual,
unless I was in a hurry* you'd change 2, 4 , 5 (and only 5th if you were
on the highway, 2nd redlined way past go directly to gaol speeds).
Realistically a 4 speed would have been plenty (although the moonshot
overdrive made it cheaper to run on the highway)

Should be able to feel it when you go over the torque peak, the rate of
acceleration slows, past the HP peak you should be able to feel that
too. And the sound of a motor thrashing itself to death is remarkably
obvious to the untrained ear, let alone anyone who has a modicum of
mechanical sensitivity. If anything I think you'll find most people will
err on the side of caution, shortshifting long before they have to if
they don't have a tacho.

Call me an old fart if you will, but mechanical aides to rider/driver
skill (ie ABS, traction control etc) create dependency, and that to a
lesser extent goes for tachos. Outside the racetrack they're a nice to
have not a must have. Oh and they're not very expensive aftermarket.

JL
*In a hurry you'd use 1,2,3 and be careful to control the wheelspin

 

You can tell a guy who only rides sports bikes Think about it this

While I agree with your point there, what I am getting at is that it
certainly wouldn't be a _detriment_ having 6 gears. You've given plenty of
reasons why you don't _need_ more gears, but none as to why less gears is
_better_.

That's exactly it, though. To the untrained ear, you'll be always erring on
the side of caution and never getting to that peak power.
I agree they aren't a must have, but they are VERY useful. As for
after-market, how many of them are suitable for twin cylinder engines? (I
don't know, so that's a legitimate questions.) I would have thought they
would have all been designed for 4 cylinder jobbies. Also, do they come in
sizes other than "Fully Sik"?

You're right, they do often create dependancy, and they shouldn't be a
substitute for skills, but that doesn't make them any less of a good idea.
ABS may not save lives in the statistics, but it's saved my life on at least
one occasion (in a car, not on a bike). You can take it to the fullest
extent and say that we shouldn't have speedos. (Should just be able to tell
engine speed from the sound of the engine, and work out our speed from the
gearing.) Or other aids to skill (like sticky tires, quality brakes, etc
etc). Advancements happen for a reason. Things that aren't useful don't tend
to hang around too long.

That having been said, I don't really see the need for a tacho on an
automatic car.

 

so put it this way , is more gears better ???

a lot are designed for multi cylinders and you can get full sik and no sik
versions

www.rbimports.com.au are one supplier

but nowadays you can get full bling multi purpose items

dont see the need but they can be useful

 

Hmmm <thinks>, OK get your point, perhaps I didn't explicitly state it -
but it's implied in the two paragraphs you snipped - the extreme example
of the jag which really only needed 2 or 3 gears - adding extra gears
doesn't add a lot of value if you have to go through them on the way to
the gear you need. It's ok in a H pattern manual car you can jump
directly to it- bikes being sequential don't allow that easily (some
don't allow it at all)

But you see that's the sports biker in you coming out, do you think a
learner wouldn't be better off erring on the side of caution ? Might
increase his/her life expectancy a little, and as their experience grows
so will their willingness to thrash it a little harder.

Hehe, yes you can get things other than "fully sik moite". What you get
depends on how much you want to spend - the budget option is to pull one
out of a v twin bike. Otherwise you buy something that takes a feed off
the coil wire etc, there's ones around that do twins.

Oh no doubt, but it's not a substitute for learning to drive and ride
properly in the first place. I think all learner drivers should be
forced to spend their first year on the road in a Morry Minor or
something with equally atrocious handling and brakes, after doing a
compulsory handling course a la the bike Ls course.

hehe you'll be surprised to hear me say, yep, I agree there too !
Dependency on speedos is what leads too many people to drive too fast
for the conditions. Were you aware that a "blind test" where people had
their speedos covered up showed that they generally did around the speed
limit in most cases anyway,(this was before the NSW government got silly
and started putting 6000 speed zones per Km), when told to drive at a
comfortable speed without fear of being booked, the vast majority of
drivers did about 40-50K on tight streets and busy areas 60-70 in more
open roads and between 80 and 120 on the open road.

Speedos cause people to go too fast for the conditions when it's wet or
poor visibility (it's an 80 zone so I must do 80 - even though cyclone
tracy has just blown in and I can't see 3metres in front of me)

We only need speedos to avoid getting booked, they serve no other useful
purpose that couldn't be better handled by driver training and booking
people for driving dangerously.

Sure, ABS and all the other aides are useful, don't get me wrong, they
DO add value, but they add it mostly by making cars more easily
controllable by the lowest common denominator, which I'm not entirely
convinced is a good thing

Indeed

JL

 

so put it this way , is more gears better ???
Not necessarily. In some cases yes, in other cases it's no
better. Depends on how tight the powerband is, amongst other things. I have
6 gears on the ZX10. I actually use 1,2,3,4 and 6. I would really like what
is currently 5 to be what is currently 6, and I would like 6 to be a
_really_ tall overdrive, for when I have to do an hour or 6 down the hume
boringway.

For what? The gearbox, even when shifted into "1", will shift up
if you try to put the engine past it's redline. (At least it does in my auto
car.)

 

That's a fair point. I think it has not so much to do with number of gears,
but more the usefulness of each. I would rather 5 useful gears rather than 4
useful and 2 useless, but I would rather 6 useful gears to 5 useful gears.
(Or, for example, 4 useful and 2 not instead of 3 useful and 2 not.)

Yes, but learners do exactly that. Learn. And a tacho is useful for the
learning too. Prior to hopping onto my first road bike to ride, I had never
ridden a bike with a tacho. I had no idea on the ag-bikes I was riding how
near I was to redline. I still don't really. But when I started riding the
GPX around, I started out erring on the side of caution. Like 2000-3000rpm.
But, because I had a tacho and could see that I had another 11000rpm left
till redline, I new that what I was currently using wasn't just "erring on
the side of caution" but was no-where near the bikes capability. Prior to
that I had no idea that bikes could rev that high. And the first time I
heard the sound from the riders seat, I though the engine was going to blow
up. Tacho told me I still had a few thousand to go though. Without a tacho,
I would have backed off long before, and would never have _really_ learned
to get the best out of the GPX. It would have made my time on a 250 all the
more tortuous.

I'd settle for making everyone drive a Datsun 180B. (Ahh, it was a great
car. 3 speed auto wagon. With AM Wireless no less!!!)

<snip>
Actually, I'm not really surprised, and I agree wholeheartedly with
everything you said there. But, we do really _need_ speedos these days to
keep below the speed limit (rather than keep at a safe speed) and keep above
the poverty line.

I agree with your idea in theory, but I'd rather the lowest common
denominator had ABS if it's all the same to you. Might mean there is less
chance of them slamming into me up the rear.

 

Basically, yeah. Quantity isn't of value of itself, match the qty of
gears to the torque characteristics of the engine - given the vast
majority of bike engines are very revvy then 6 sp is a good idea,
doesn't mean they're all best of with that no. though.

Sure and i know someone who despite having a tacho never revved her
Bandit 250 to half it's redline - was uncomfortable with the sound it
made. $10 says you'd have accidently "over-revved" the GPX and then
asked someone and found out it was OK if you didn't have a tacho...

As I said, nice to have not must have, lets not lose sight of the fact
that the VTR250 has a relatively low redline (6500 ?) and hence it's in
the same "sound range" that car drivers are used to.

I think you're being way too kind, a 180B can be made to handle quite
well The Morry is far crueller.

Yup, like I said, it's only use is to keep you from getting booked, an
approach that would be more usefully served in removing speed limits and
booking people for dangerous driving and forcing more training before
they got a licence. Dreamland though.

More likely to do what most people do when the ABS kicks in - take their
foot off the brake !

 

Because thats what the rules limit them to?

OK, You're an old fart John...

;-)

big (we've still gotta get round to that xmas beer sometime, eh?)

 

Here's a point of reference James, I started riding on my Spada (with a
tacho). 9 months later I bought the Monster which doesn't have a tacho.
As I was riding it out of the dealership I remember thinking to myself
"Hmmm, first thing I've got to do is get a tacho for this thing". A week
later I still hadn't got around to it and it seemed somewhat less
important. Its gonna be five years old in a couple of months and it
still doesn't have a tacho, and thats 'cause it doesn't need one.

Some motors, like the Ducati 2 valve 750, _really_ don't need a tacho.
The reason why can be seen in these:

http://www.moto-one.com.au/performance/750ssmonstercarb.html

http://www.mototuneusa.com/yamaha_r6_dyno_sheet.htm

A Monster750 dyno chart and a Yamaha R6 dyno chart (pulled out of google
as representative of the characteristics of an inline 4 sportsbike motor)

Notice how the power curve for the v twin drops significantly past peak
power (as in around 10% below peak) and that peak power is a good
1500rpm below redline. Compare that to the R6, which holds on to within
4% or so of peak power all the way to the rev limiter.

On the 4 cylinder bike, optimal gear changes are pretty much decided by
the rev limit - you basically want to rev it as fast as you can without
it blowing up (or doing damage that will make it blow up during the
race) before you select a higher gear, because at the lower rpm in the
next gear you are developing less power. On the vtwin, its pretty
obvious even to an untrained arse-dyno that you are not accellerating as
fast once you pass peak power, and youve got almost 2000rpm to notice
before you hit redline - if you're going to drop say 1500rpm on the
gearchange, once you've reved more than about 750rpm past peak power,
you'd be making as much or more power on the next higher gear, and its
pretty obvious from the riders perspective when that happens...

big

 

I believe that should be "_It's_the only way to be sure", big man.

IK,
if they ever do Fahrenheit whatever-temperature-celluloid-film-burns, and
movies have to survive through people memorising them, I bags "Aliens".

 

In aus.motorcycles on Tue, 12 Oct 2004 10:48:43 +1000

50cc GP bikes used to have 18 or 20 gears.

I think several early 125s had 7 or 8.

Zebee

 

I believe that should be "_It's_the only way to be sure", big man.[/QUOTE]

I'll take your anorack wearing word for it Marko ;-)

Heh - seen Alien Vs Predator yet? Crap story, _pretty_ cgi...

big

 

In aus.motorcycles on Mon, 11 Oct 2004 22:17:46 +1000

I have a VDO tacho that works fine on the Guzzi, but had to be modified
for the Yam single.

Only goes up to 10 grand, but that's fine for my bikes.

Zebee

 

Despite everything I've read since its release in the US, I couldn't stay
away (at least I snuck in on a ticket I'd bought for 'Dodgeball', so those
$11 don't count towards the bottom line of 'AvP'). I kept thinking 'How the
hell can you screw up a movie with that premise? It can't be done. They
could've put the bullhorn in my brother's hand and the result should've
still rocked the house.'.

35 seconds in, "OK, so that's how."
Then followed:
-icebreaker named after the ship which recovers a crashed UFO in an episode
of the X-Files.
-"SO-AND-SO WHALING STATION" in ****-off big letters on an abandoned whaling
station building.
-I bet the Akrapovic off the ZX-6 against a 4' section of roof guttering
that's gonna turn out to be a penguin...20 seconds pass... all right, make
with the guttering, muthafucka.
-Violins, eh?
-shot sequence: close up of screaming victim, blur of slashed blade, cutaway
to red splash on surroundings.
-"The pyramid's changing again!"
-Blade cuts clean through something, said something lingers, then parts.
....
At one point, I actually found myself back at the side of the road after the
R1 stack, reliving that sensation of being in so much pain that I was unable
to move; Freud at work, perhaps...?

End credits came up, I rushed home, rolled around in the mulch at the base
of the bushes out front to exfoliate, went inside, showered, turned the tv
on to try and find something to cleanse my mind, eyes and ears of what I'd
just seen... ah, late night sci-fi on Ch.7. "Universal Soldier", which,
since I saw it at the movies when it originally came out in 1991, has pretty
much been the crapulent yardstick by which all other crap action-sci-fi gets
gauged ("The Chronicles of Riddick" scored a normalised 0.85). After "AvP",
it was watchable.

The only positive is that it depleted my guttedaline (the hormone which
regulates how gutted you feel) level, which came in handy over this past
weekend.

 

Dave's not here, man...

 

And Dave gives it 0 stars...

TB