barryG wrote:why have they bothered with the old 500 still?

That'll be for the very few people who feel the need to blow off 400 Burgers on German Autobahns once in a blue moon...

Maybe once in a blue moon for you, but Im on them loads

Vor uns liegt ein weites Tal
Die Sonne scheint mit Glitzerstrahl.....

gn2 wrote:Drag squares with speed which is why to raise top speed progressively bigger horsepower increases are required.
(I used to have a PPL and instructed in gliders so I understand drag)

Congrats on the PPL GN2.
I'm a designer working in the aviation industry including military projects, I also own a company that writes simulator software, previously involved in land transport.

"drag squares with speed" is a handy theoretical rule of thumb for when detailed aero knowledge isn't required.
In practice things are more complex and do not progress in such a linear fashion.

It was clear from day one that Data knows a bit about motorcycle engines, so I am not going to try to tell him how they work.
Similarly, I know a bit about airflow and dynamics (and unusual propulsion types), not everything but I get by.

I am not on the attack, just giving things towards accuracy because they happen to be within my home turf.

Bluebottle wrote:I am not on the attack, just giving things towards accuracy because they happen to be within my home turf.

But how accurate do you need to be for scooters doing less than 100mph?
If the Maxsym 400 is not significantly more powerful than an X10 and if the X10 is slippier it could match the Maxsym for top speed.
That's a lot of "if".
Time and proper testing will tell.
The earth isn't flat you know, who would have thought it....

I meant the accuracy of what you were saying but never mind, forget it.

A 50cc Kreidler did 140 mph back in the sixties - aerodynamics makes a difference.

Weight is significant to off the line acceleration.
Aero drag is significant for top speed.
Aero drag differences are going to kick in hard from 50 mph upward
The rpm for max torque is really important for automatics
Reading between the lines is an art form

Guys, i love reading stuff like this and i your knowledge! Great reading and simply an online knowledge tool, this forum!

Yup, superb discussion that has been very helpful to me in planning what I intend to do or not do next. Thank you one and all.

Geoff.

gn2 wrote:If the Maxsym 400 is not significantly more powerful than an X10 and if the X10 is slippier it could match the Maxsym for top speed.

Theoretically, it would also depend on the final gearing. My 250 bounces readily off the rev limiter when there is still a good bit of go left from the motor.

Found some performance stats on Scoot Infos for max speed, acceleration from standstill to 100metres, and fuel consumption.

X10-350 88mph, 7.4s, 4.2 l/100km
Maxsym 90mph, 7.9s, 4.6 l/100km
Burger 400 91mph, 7.8s, 5.2 l/100km
Satelis 400 (Master engine) 94mph, 7.2s, 4.7 l/100km.

Looks like the X10's smaller capacity pays off in fuel consumption, and the lardy Burger and Maxsym lose out off the line. And although gearing is unknown, the slippery Satelis pulls away on max speed.

I often wondered about gear ratios at the lower end too.
ie when auto-bikes are restricted from putting all there power down at launch how much is a natural product of their torque curve and how much is govenor controlled via jetting/electrics etc?

Electric bikes can put all their torque down at zero revs so they have a control circuit to the rider being ejected.