Honda VTR1000 Twin SP1 & SP2 Gearbox

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Designed to complement the enhanced performances obtained from blueprinted and tuned engines.

The gearbox will allow you to use the full potential of improved performance.  The positive engagement system, three undercut engagement dogs per gear, gives almost continuous power output to the rear wheel and extremely rapid shifting.  The ratio's are designed to give maximum acceleration in all gears unlike the road use gears supplied by Honda.  By necessity a road machine must be tractable in town with two people and have a high cruising speed but not at peak revs.  This effectively reduces the overall acceleration and obtainable top speed.

 

Gear Ratios

Nova  Gearset                          %  Drop           Standard Honda Box                % Drop       

 

1st      16 - 34        2.125:1                                1st      13 - 32        2.462:1  
                                                 )    23.2%                                                                 )     26.4%
2nd     19 - 31        1.631:1                               2nd     16 - 29        1.813:1 
                                                 )    17.2%                                                                 )     21.2%
3rd      20 - 27        1.350:1                                3rd      21 - 30        1.429:1 
                                                 )    13.0%                                                                 )     15.5%
4th      23 - 27        1.174:1                                 4th      25 - 31        1.240:1   
                                                 )    11.0%                                                                 )     10.5%
5th      23 - 24        1.043:1                                 5th      25 - 27        1.080:1  

                                                 )      7.8%                                                                 )     11.1%

6th      26 - 25        0.962:1                                 6th      26 - 25        0.962:1
                                 

Overall Reduction 1st - 6th      54.7%            Overall Reduction 1st - 6th           60.9%

 

The percentage figures are, if multiplied by the engine rpm. will give the rev drop between  the gears.  For example, top gear on the road bike at 10,000 rpm is equivalent to 1,110 rpm, whereas the Race Bike ratio has a rev drop of 780rpm.

The overall reduction ratio for a race gearbox  of this type of engine is normally around 55%, which means that 1st gear will always be slightly less than half the maximum speed obtainable, which differs considerably from the lower geared road bike as illustrated by these figures.

The gearbox comprises of input shaft and all loose gears.  It is assembled using standard Honda bushes, spacers, circlips and output shaft from the original machine.

 

Price £1100 + VAT (if applicable) & carriage