I am about to replace the chain and sprockets on this noble beast and
so begins the Quest for the Unknowable Right Answer:

Should I change the gearing, or in this case, the sprocketing?

It's a cute little in-town cruiser and bar hopper but it wasn't made
for sustained
highway riding. It's too rev-vy for that:

It redlines at 20 mph in first gear, I rarely take it up to 70 mph. I
know a few less revs at highway speed in 6th gear would be a bit more
pleasant.

Should I give it taller gears? Would I regret reducing the crusing
revs by about 8 or 10 percent with a corresponding loss of low gear
grunt?

What say ye, oh Fount of All Knowledge? <ducking for cover>

Biker Dude

On Nov 23, 12:15*pm, Biker Dude <jacobsenpa...@hotmail.com> wrote:
>
> Should I change the gearing, or in this case, the sprocketing?

It's up to you. The only way most people are satisfied with the answer
to the gearing question is experiencing what happens when they do it.

You can install a front sprocket with one tooth more (if you can find
one that fits in the space available, or install a rear sprocket with
three teeth less, and you will
usually achieve a gearing situation where sixth gear feels like it's
halfway between
sixth and an imaginary seventh gear.

If you live in flat country and you don't have to fight head winds,
you just might
like such an arrangement.
>
> It's a cute little in-town cruiser and bar hopper but it wasn't made
> for sustained highway riding. *It's too rev-vy for that:

Oh, get real. I was talking to a guy at a motorcycle hangout and he
said that he and his "partner" frequently rode to San Francisco and
back together on his KZ550 (about 800 miles round trip) and the
biggest issue was that there was no way to carry souvenirs or
antiques ;-) home because the machine was so small.

> It redlines at 20 mph in first gear, I rarely take it up to 70 mph. *I
> know a few less revs at highway speed in 6th gear would be a bit more
> pleasant.

Believe it or not, the engineers at Kawasaki *knew what they were
doing* when they selected the transmission gearing and the final drive
ratios.

A modern 4-stroke inline-four has a very short stroke in order to
reduce piston ring flutter at high RPM. Kawasaki designed their engine
in order to save wear and tear on the piston rings, so, if you're
cruising along at 5500 to 6000 RPM in sixth gear, you're NOT hurting
the engine.

If you're out on the road on a long trip and you're riding close to
the red zone on your tach for long periods, be sure to check your oil
level every day.

> Should I give it taller gears? Would I regret reducing the crusing
> revs by about 8 or 10 percent with a corresponding loss of low gear
> grunt?

A 7.5% change in final drive ratio will generally put you right
between 6th and 7th
gears, in terms of cruising RPM.

Like i said, it depends on whether you have hils to climb or have to
battle head winds or carry a passenger. If you find that you have to
downshift two gears instead of one gear to pass a truck on a hill,
you've over-geared your final drive.
>
> What say ye, oh Fount of All Knowledge? *<ducking for cover>
>
> Biker Dude

Mark Olson <(E-Mail Removed)> writes
>Biker Dude wrote:
>> I am about to replace the chain and sprockets on this noble beast and
>> so begins the Quest for the Unknowable Right Answer:
>>
>> Should I change the gearing, or in this case, the sprocketing?
>>
>> It's a cute little in-town cruiser and bar hopper but it wasn't made
>> for sustained
>> highway riding. It's too rev-vy for that:
>
>What criteria did you use to come to that conclusion?

Sounds to me like someone has changed the gearing already.

It's more than 20 years since I rode a 550 Ltd but back then I was happy
to run it at a steady (indicated) 100mph. I've ridden a vanilla Z550 & a
GPz550 since then & they were both happy enough around 100mph.

[]
>
>> Should I give it taller gears? Would I regret reducing the crusing
>> revs by about 8 or 10 percent with a corresponding loss of low gear
>> grunt?
>
>Regardless of what sprockets it currently has, replace them with
>the original sizes, which is a 16T front and 38T rear. Chain is
>#530, 100 links. Increasing the gearing 8 to 10 percent higher
>would seriously screw up what is a nicely geared bike.
>
I'd second that - check the gearing & if it's not standard I'd change to
standard.
--
Bob Scott

??? ??? ????? ??? <(E-Mail Removed)> wrote:

> A modern 4-stroke inline-four has a very short stroke in order to
> reduce piston ring flutter at high RPM.

Utter nonsense.


--
BMW K1100LT Ducati 750SS Honda CB400F Triumph Street Triple
Suzuki TS250ER GN250 Damn, back to six bikes!
Try Googling before asking a damn silly question.
chateau dot murray at idnet dot com

Biker Dude <(E-Mail Removed)> wrote:

> I am about to replace the chain and sprockets on this noble beast and
> so begins the Quest for the Unknowable Right Answer:
>
> Should I change the gearing, or in this case, the sprocketing?

If you want. I wouldn't.

>
> It's a cute little in-town cruiser and bar hopper but it wasn't made
> for sustained
> highway riding. It's too rev-vy for that:

That's a 550 Kawasaki for you. They're all like that. I've owned a
couple and ridden many more.

>
> It redlines at 20 mph in first gear, I rarely take it up to 70 mph. I
> know a few less revs at highway speed in 6th gear would be a bit more
> pleasant.
>
> Should I give it taller gears? Would I regret reducing the crusing
> revs by about 8 or 10 percent with a corresponding loss of low gear
> grunt?

I'd leave it stock. There isn't that much bottom end in those engines
anyway. Not much mid-range either, come to that.

And now, I will see what KrustyUS advocates. I'll expect a ream of
superfluous info about gearing.

<Checks>

Yup, thought so. At least he tells you to retain the stock gearing, so
that's three or four votes in favour and none against.


--
BMW K1100LT Ducati 750SS Honda CB400F Triumph Street Triple
Suzuki TS250ER GN250 Damn, back to six bikes!
Try Googling before asking a damn silly question.
chateau dot murray at idnet dot com

"The Older Gentleman" <(E-Mail Removed)> wrote in message

> Yup, thought so. At least he tells you to retain the stock gearing, so
> that's three or four votes in favour and none against.

Make that 5-0


--
Dave
ex Motorcycle Maintenance Workshop
http://tinyurl.com/4mhaw

On Nov 23, 1:31�pm, totallydeadmail...@yahoo.co.uk (The Older
Gentleman Crapped In His Diaper Again) and thinking that nobody would
notice the smell, wrote:
> ??? ??? ????? ??? <macmi...@gmail.com> wrote:
>
> > A modern 4-stroke inline-four has a very short stroke in order to
> > reduce piston ring flutter at high RPM.
>
> Utter nonsense.

Compared to a twin cylinder engine of equal displacement, inline-fours
*do* have a very short stroke, so they can rev up to higher RPM than
the twin, thus producing about 40% more power.

A few KZ550 specs:

Bore x Stroke: 58mm x 52.4mm

Power: 53 @ 8500
Torque: 35 @ 7000
Top Speed: n/a
RPM @ 60: 4902

Piston speed (in feet per minute) = .166 X 2.06 inches X 8500 RPM =
2913 fpm

At 7000 RPM, the piston speed is 2399 feet per minute.

At 60 mph, the engine is only turning 4902 RPM.

Piston speed is only 1700 fpm at such a relaxed cruising speed.

Now, compare what racing speed tuners say is a reasonable piston speed
for production based engines.

4500 feet per minute.

You would have to rev the KZ550 (or any engine with the same stroke)
over 13,000 RPM to reach the theoretical piston speed where piston
ring engineers started running into trouble with ring flutter. (1)

Nowadays, racing engines (like Ducati Corsa engines) are routinely
reaching piston speeds of 5000 feet per minute and consequently have
very short useful lives due to piston ring flutter exacerbated by the
low friction slipper pistons rocking in their bores.

The Norton V-8 protype engines of a decade ago were reaching piston
speeds of 5500 feet per minute...

(1) Back in the mid-1980's, Suzuki was racing their prototype
GSXR-750's in European endurance racing. They had to rev the engines
up to 13,000 RPM to get the 130 horsepower they wanted.

American roadracers drooled at the thought of getting their hands on
an engine that revved up that high and produced so much horsepower.

But the racing GSXR's had special Carillo I-beam connecting rods that
cost $1000 a set.

The production GSXR-750's that we got only had about 90 horsepower and
were RPM-limited to only about 11000 RPM because they used cheap
production connecting rods.

??? ??? ????? ??? <(E-Mail Removed)> wrote:

> > > A modern 4-stroke inline-four has a very short stroke in order to
> > > reduce piston ring flutter at high RPM.
> >
> > Utter nonsense.
>
> Compared to a twin cylinder engine of equal displacement, inline-fours
> *do* have a very short stroke, so they can rev up to higher RPM than
> the twin, thus producing about 40% more power.

Quite right. Never said they didn't.

Short strokes equal higher revs, greater valve area, less tall engine,
and lower piston speed. Rocking of pistons in bores is nothing to do
with it.

To say that ring flutter is the reason why people use short strokes is
just daft.

<snip a raft of the usual irrelevaqnt technical stuff designed to
obscure your initial *******s>


--
BMW K1100LT Ducati 750SS Honda CB400F Triumph Street Triple
Suzuki TS250ER GN250 Damn, back to six bikes!
Try Googling before asking a damn silly question.
chateau dot murray at idnet dot com

Biker Dude wrote:

> I am about to replace the chain and sprockets on this noble beast and
> so begins the Quest for the Unknowable Right Answer:
>
> Should I change the gearing, or in this case, the sprocketing?

Nope. Yup. Maybe.

Kawasaki knew what they were doing when they came up with the gearing. It is
your bike though, so do what you want. If it makes the bike better for you,
if it makes you a happier rider, why not?


>
> It's a cute little in-town cruiser and bar hopper but it wasn't made
> for sustained
> highway riding. It's too rev-vy for that:

Even after all these years of riding Japanese middleweight fours, I am still
in awe of the engine speeds and reliability they obtain.


>
> It redlines at 20 mph in first gear, I rarely take it up to 70 mph. I
> know a few less revs at highway speed in 6th gear would be a bit more
> pleasant.

If the low first gear is a pain, set off in second.

>
> Should I give it taller gears? Would I regret reducing the crusing
> revs by about 8 or 10 percent with a corresponding loss of low gear
> grunt?

You -may- regret it. OTOH, sprockets aren't vastly expensive.

Providing it fits, try going up one tooth on the front. Ride around for a
bit. Does the bike still pull without having to drop a gear?. Next, drop
two teeth off the back.

One thing to be aware of though is you may end up at, say, 4000RPM in 3rd,
where previously you'd be at 3750RPM in 4th. Just an example, no need to
hit me with maths...


>
> What say ye, oh Fount of All Knowledge? <ducking for cover>

You won't kill the bike. You may make it better for you, you may make it
worse. If you lose instant throttle response, or find yourself flicking
twixt 5th + 6th at motorway/highway speeds, it is a minor task to restore
the gearing.

If the revs bother you, mask your rev counter

>
> Biker Dude

On 24 Nov, 10:59, Mark Olson <ols...@tiny.invalid> wrote:
> M.Badger wrote:
> > If the revs bother you, mask your rev counter
>
> That is almost always the right answer when someone says their bike revs
> too high on the highway.
>
> With stock gearing, a 130/90-16 rear tire and an overall reduction
> of 6.25 in 6th, the KZ550 is turning about 5000 RPM at 60 mph, which
> is not high at all. *Speed in 1st gear at redline is about 42 mph, so
> if the OP is really only getting up to 20 mph in 1st gear at redline,
> someone has *really* screwed with the gearing.

Looks that way.

They're lovely little engines, those 550s. I lost my licence on a 1984
GPz550, the first ZX model. "In excess of 118mph" it said on the
summons. The police who nicked me observed that I was actually pulling
away from them at the time, but the police car would go no faster, so
118 was the figure. The bike was indicating just under 130 at the
time.

I also took a GT550 (the shaft-driven one: did you ever get that in
the US) around France once. That had what was basically the engine
from the first GPz550H1 in it, so very whizzy but not as peaky as the
ZX. Still needed winding up, though. That would easily indicate 120mph
solo. Comfy, too: they sold zillions of the things here to despatch
riders.

The LTD is a rare beast in the UK. Generally, we don't do the cruser
thing, and those who do tend to buy ones designed as cruisers from the
ground up, rather than the bastardised roadsters that predominated in
the late 1970s/early 1980s.