So what has changed the performance across the rev range? Oh yes
let me tell you that the most important change as everyone apparently
thinks it to be on this bike is the adoption of a humble but trick
Ucal UCD 32 venturi carburetor in place of the Delphi-supplied throttle
body type fuel injection system. The bike in carbureted form makes
21.04 PS at 8500 rpm, one horsepower more than in fuel injected
form. In the torque stakes both make the same amount of twist force
- 19.12Nm but the 220DTSi does it at 7000rpm which is 500 revs more
than the 220 DTS-FI. A word of caution though now that everyone
has seen the enhanced power output and the resultant performance
that has emerged from the bike and if this seems to be the mantra
for the other bike makers to go and slap on a large carb, I am afraid
doing so without more tech tweaks internally would only douse the
flame front!
Born under the patronage of Rajiv Bajaj, the spiritual father of
the Pulsar range since its advent has been the genial Joseph Abraham
who heads a close knit team of young enthusiastic engineers wedded
to making great motorcycles and not afraid of pushing the envelope
to achieve their desired objectives. To many it might look a step
back in tech and time but that's not so when you see what they have
achieved with a set-up which is powerful, fuel efficient and yet
comfortably meets the emission standards. Central to the carbureted
220 is the DTSi top end but everything else is new. There is a new
combustion chamber design, all new port geometry for optimized thermodynamics,
newer valve coat materials to eliminate carbon formation and also
friction reduction and an all-new camshaft. This is indeed a hot
cam featuring both higher lift and duration and this set-up seems
to be the best optimized DTSi top end ever.
While cylinder dimensions have remained the same as in the DTS-FI version
at 67 x 62.4mm, the short-skirt piston now comes with new material (screen
printed graphite based molycote) which helps reduce friction and also
improves the engine's anti-seizure qualities. An engine which is yet air-cooled
needs to keep its operating temperatures intact and to do that it needs
the oil to maintain a steady temperature. There is a larger oil cooler
on the 220 DTSi with 33 per cent more cooling area and if that's not all,
Joseph's team have developed oil jets to spray on the con rod's big end
to give positive oiling not just to combat the high forces acting on this
high revving engine but also to cool the piston skirt as well in the process.
An all new ignition system with engine temperature sensors built into
the cylinder head helps monitor engine mapping all across the rev band
and in the process the rider doesn't encounter any flat spots which might
detract from the sheer riding experience but the torque delivery and very
low NVH levels are great rewards. Even with a carbureted set-up, the bike
now features an auto-choke which is so unobtrusive yet practical and highly
effective in its operation.
