View source for Rotax V990

==General Specifications==

=== Weight ===

The December 2001 V990 workshop manual lists the engine weight as 143 lbs.  The October 2003 V990RR workshop manual lists the engine weight as 148 lbs.

=== Displacement and Compression Ratio ===

According to the December 2001 V990 workshop manual:

<div style="margin-left: 2em;">
{| class="wikitable"
!  colspan="2" | &nbsp; !! Displacement !! Compression Ratio
|-
!  colspan="4" | RSV, RSV-R  Tuono, Mille
|-
| &nbsp; || Up to 2000 || 997.6 cm&sup3; || 11.4&plusmn;0.5:1
|- 
| &nbsp; || 2001 and later || 998.00 cm&sup3; || 11.8&plusmn;0.5:1
|- 
! colspan="4" | SL Falco
|-
| &nbsp; || Up to 2000 || 997.6 cm&sup3; || 11.4&plusmn;0.5:1
|- 
| &nbsp; || 2001 and later || 998.0 cm&sup3; || 11.8&plusmn;0.5:1
|- 
! colspan="4" | RST Futura
|-
| &nbsp; || &nbsp; || 997.62 cm&sup3; || 11.8&plusmn;0.5:1
|-
! colspan="4" | ETV Caponord
|-
| &nbsp; || &nbsp; || 998.00 cm&sup3; || 10.4&plusmn;0.5:1
|}
</div>

=== Cam Timing and Lift ===

According to the December 2001 V990 workshop manual, the RSV Tuono, RSV-R Mille, and SL Falco all have the same 262&deg; intake and 259&deg; exhaust.  The 2001 and later RSV Tuono and RSV-R Mille have a 0.45in (11.40mm) intake lift, and all other intake and exhaust valve lifts for the RSV Tuono, RSV-R Mille, and SL Falco have a 0.42in (10.60mm) intake and exhaust valve lift.  The RST Futura has 259&deg; intake and exhaust, with 0.42in (10.60mm) lift.  The ETV Caponord has 242&deg; intake and exhaust, with 0.37in (9.5mm) lift.

==Slipper Clutch==

Pneumatic Power Clutch/slipper clutch/PBTL System details are in [https://www.apriliaforum.com/forums/showthread.php?65496-Aprilia-Rotax-and-V990&p=745935&viewfull=1#post745935 this apriliaforum post].

<blockquote>
PBTL SYSTEM

The PBTL system on the RSV 1000 reduces the ‘braking’ torque transmitted by the engine during deceleration.

OPERATING PRINCIPLE:

Line 1 is connected to the intake passage whereas line 2 – downstream of the retaining valve – is connected to the airbox via the throttle valve. Line 3 links line 2 to the airbox when the throttle valve opens to an angle greater than 10-12 degrees.

During deceleration, the system configuration is as shown in the figure.

The negative pressure in the intake passages is transmitted to the clutch membrane via line 1+2.

The ‘retaining’ valve (non-return) comes into play and stabilises the pressure in the line.

Consequently, the clutch discs slip and reduce the torque.

During acceleration (throttle valve >12°), the valve, connected on the throttle unit axis, links up line 2 with the airbox, thus cancelling out the pressing effect on the clutch unit and taking the clutch pack back to its original position.
</blockquote>