Insight
into MotoGP
Having
had more fun at the Museum on the Monday and wondering why the LE was
not running well on the way home I decided to have a look at it. It
turned out that a burnt out exhaust valve on the left cylinder was
the culprit. It was not until I started to grind in the valves that I
was able to see there was no seat contact on about a third of the
valve. No wonder there was no compression! A new valve was fitted and
performance restored.
On
Thursday I headed out to Ripley village hall for the meeting. It was
not a good ride as there was so much traffic. I think I filtered
almost all the way from home, around the M25 to the A3. I arrived
late but still in time for the start of the talk by Neil Spalding.
Those of you who follow MotoGP will have heard him many times on
Eurosport talking of the technological developments that the teams
are coming up with. He explained about how the power was delivered to
the rear wheel and how it relates to the firing order of the engines.
Different configurations give differing power delivery. It seems that
a vee formation is good for even power delivery with the crankshaft
having the minimum variation in momentum as the pistons slow at the
top and bottom of each stroke. He explained the difference between
bike and car engines and how the crankshaft on a bike was much
heavier to ensure a smooth power delivery. In MotoGP you do not want
200 plus bhp coming in like putting on a light at the switch. He
spent some time talking about the Honda RC211V vee 5 engine of 2002 and that
the carburration was split between the front 3 cylinders and the rear
2 at certain throttle openings.
Honda Vee 5 engine.
To manage the power when the throttle is opened only the front 3
cylinders were used so that the power delivery was metered very
accurately and above all smoothly. There is even computer control
that compensates for the angle of lean. Once you have something that
works the chassis then has to do its job. Apparently the centre of
gravity for a MotoGP bike is somewhere in a 6mm square on the machine
and it is not easy to find. The design of the engine and where the
gearbox should go is very important so things can be positioned in
the best place. There was some discussion about why Ducati's had been
so good with Casey Stoner and with no-one else. It turns out that he
just rode every corner like he was going to crash. Now Ducati are
sorting the problem out and it seems they had too rigid a chassis.
With the modern bikes reaching silly angles of lean the suspension
that operates up and down in the plane of straight line riding do not
work when cranked over at 60 degrees. If there is no give the wheels
just bounce and traction is lost and down you go. To get the tyres to
continue gripping something has to give so the chassis is designed to
flex in that plane to achieve this.
Bautista in action.
At present the MotoGP teams are
signing up people who can slide the bikes and this gets around a
number of the handling issues with riders skill. Talking of tyres,
Pirelli had made tyres to suit the bikes but with the change coming
using Michelin tyres the bikes will need to be designed for the tyre
and not the other way around. Neil gave us an immense amount of detail
about what manufacturers had done in their quest to be number one. It
was a very enjoyable evening that gave an insight into making a
winning bike.
