Off-road competition motorcycle

1. An off-road competition motorcycle comprising:

a tubular trellis frame ( 5 );

an internal combustion engine ( 2 ) mounted on the frame;

a front wheel ( 3 ) and a rear wheel ( 4 ) mounted on the frame; and

a fuel tank ( 11 ) mounted at a rear end of the off-road competition motorcycle ( 1 ) and releasably secured to said tubular trellis frame ( 5 );

wherein said tank ( 11 ) comprises a sole fuel tank of said off-road competition motorcycle ( 1 ), and a lower portion of said tank ( 11 ) extends by its bottom ( 16 ) toward a yaw axis of said motorcycle ( 1 ) to an end of the tubular trellis frame ( 5 ).

2. The off-road competition motorcycle as set forth in claim 1 , wherein said motorcycle has a deadweight that applies a load on said rear wheel ( 4 ) of the off-road competition motorcycle ( 1 ) when the motorcycle is upright, and wherein further said load comprises at least approximately 53.5% of said deadweight.

3. The off-road competition motorcycle as set forth in claim 2 , wherein said load on said rear wheel ( 4 ) of the upright off-road competition motorcycle ( 1 ) is between approximately 53.5% and approximately 56% of said deadweight.

4. The off-road competition motorcycle as set forth in claim 1 further comprising an electrically operated fuel pump ( 15 ), at said bottom ( 16 ) of said tank ( 11 ), for supplying fuel to a fuel injector system of the engine ( 2 ).

5. The off-road competition motorcycle as set forth in claim 1 , wherein a top of said tank ( 11 ) is recessed for locating an insert for mounting at least one member selected from the group consisting of a controller for the engine ( 2 ); a fuel injector system of the engine ( 2 ); and a battery ( 20 ).

6. The off-road competition motorcycle as set forth in claim 1 , wherein said tank ( 11 ) comprises an arcuate segment in a region ( 23 ) facing said rear wheel ( 4 ), said arcuate segment extending from said bottom ( 16 ) to below a fuel filler port ( 22 ) in a top of said tank ( 11 ).

7. The off-road competition motorcycle as set forth in claim 1 further comprising an air box ( 25 ), disposed between a top of said tank ( 11 ) and a handlebar header pipe ( 6 ) of said tubular trellis frame ( 5 ) in a portion ( 23 ) between side covers ( 24 ) of said tubular trellis frame ( 5 ), and beneath a seat ( 12 ) of said motorcycle ( 1 ).

8. The off-road competition motorcycle as set forth in claim 7 further comprising an engine breather located in a side wall of said air box ( 25 ), said engine breather ( 30 ) fluidly communicating with said air box ( 25 ) and a cylinder head ( 32 ) of said engine ( 2 ), and having a housing arranged substantially within a framework delta ( 29 ) of said tubular trellis frame ( 5 ).

9. The off-road competition motorcycle as set forth in claim 1 , wherein said tank ( 11 ) is hinge-mounted on said tubular trellis frame ( 5 ) for pivotal upward movement relative to said tubular trellis frame ( 5 ).

10. The off-road competition motorcycle as set forth in claim 1 , wherein said tank ( 11 ) comprises a plastic.

11. An off-road competition motorcycle comprising:

a tubular trellis frame;

an internal combustion engine ( 2 ) mounted on the frame;

a front wheel ( 3 ) and a rear wheel ( 4 ) rotatably mounted on the frame; and

a self-supporting fuel tank configured as a rear mounted tank ( 11 ) mounted at a rear end of the off-road competition motorcycle ( 1 ) and releasably secured to said tubular trellis frame ( 5 );

wherein said tank ( 11 ) comprises a sole fuel tank of said off-road competition motorcycle ( 1 ), and a lower portion of said tank ( 11 ) extends by its bottom ( 16 ) toward a yaw axis of said motorcycle ( 1 ) to a vicinity of one end of the tubular trellis frame ( 5 ).

12. The off-road competition motorcycle as set forth in claim 11 , wherein said motorcycle has a deadweight that applies a load on said rear wheel ( 4 ) of the off-road competition motorcycle ( 1 ) when the motorcycle is upright, and wherein further said load comprises at least approximately 53.5% of said deadweight.

13. The off-road competition motorcycle as set forth in claim 12 , wherein said load on said rear wheel ( 4 ) of the upright off-road competition motorcycle ( 1 ) is between approximately 53.5% and approximately 56% of said deadweight.

14. The off-road competition motorcycle as set forth in claim 11 further comprising an electrically operated fuel pump ( 15 ), at said bottom ( 16 ) of said tank ( 11 ), for supplying fuel to a fuel injector system of the engine ( 2 ).

15. The off-road competition motorcycle as set forth in claim 14 , wherein a top of said tank ( 11 ) is recessed for locating an insert for mounting at least one member selected from the group consisting of a controller for the engine ( 2 ); a fuel injector system of the engine ( 2 ); and a battery ( 20 ).

16. The off-road competition motorcycle as set forth in claim 15 , wherein said tank ( 11 ) comprises an arcuate segment in a region ( 23 ) facing said rear wheel ( 4 ), said arcuate segment sweeping from said bottom ( 16 ) to below a fuel filler port ( 22 ) in the top of said tank ( 11 ).

17. The off-road competition motorcycle as set forth in claim 11 further comprising an air box ( 25 ), disposed between a top of said tank ( 11 ) and a handlebar header pipe ( 6 ) of said tubular trellis frame ( 5 ) in a portion ( 23 ) between side covers ( 24 ) of said tubular trellis frame ( 5 ), and beneath a seat ( 12 ) of said motorcycle ( 1 ).

18. The off-road competition motorcycle as set forth in claim 17 further comprising an engine breather located in a side wall of said air box ( 25 ), said engine breather ( 30 ) fluidly communicating with said air box ( 25 ) and a cylinder head ( 32 ) of said engine ( 2 ), and having a housing arranged substantially within a framework delta ( 29 ) of said tubular trellis frame ( 5 ).

19. The off-road competition motorcycle as set forth in claim 18 , wherein said tank ( 11 ) is hinge-mounted on said tubular trellis frame ( 5 ) for pivotal upward movement relative to said tubular trellis frame ( 5 ).

20. An off-road competition motorcycle comprising:

a tubular trellis frame;

an internal combustion engine ( 2 ) mounted on the frame and having at least one cylinder;

a front wheel ( 3 ) and a rear wheel ( 4 ) on the frame; and

a self-supporting fuel tank configured as a rear mounted tank ( 11 ) hinge-mounted at a rear end of the off-road competition motorcycle ( 1 ) and pivotally upward relative to said tubular trellis frame ( 5 );

wherein said motorcycle has a deadweight and applies a load on said rear wheel ( 4 ) of the upright off-road competition motorcycle ( 1 ), and further wherein said tank ( 11 ) comprises a sole fuel tank of said off-road competition motorcycle ( 1 ), and a lower portion of said tank ( 11 ) extends toward a yaw axis of said motorcycle ( 1 ) and to an end juncture of the tubular trellis frame ( 5 ), whereby said load on said rear wheel comprises at least approximately 53.5% of said deadweight.

21. The off-road competition motorcycle as set forth in claim 20 , wherein when said off-road competition motorcycle is in an upright position said load on said rear wheel ( 4 ) of the off-road competition motorcycle ( 1 ) is between approximately 53.5% and approximately 56% of said deadweight.

22. The off-road competition motorcycle as set forth in claim 20 , wherein a top of said tank ( 11 ) is recessed for locating an insert for mounting at least one member selected from the group consisting of a controller for the engine ( 2 ); a fuel injector system of the engine ( 2 ); and a battery ( 20 ).

23. The off-road competition motorcycle as set forth in claim 22 , comprising an electrically operated fuel pump ( 15 ), at said bottom ( 16 ) of said tank ( 11 ), for supplying fuel to a fuel injector system of the engine ( 2 ).

24. The off-road competition motorcycle as set forth in claim 20 , wherein said tank ( 11 ) comprises an arcuate segment in a region ( 23 ) facing said rear wheel ( 4 ), said arcuate segment extending from said bottom ( 16 ) to below a fuel filler port ( 22 ) in a top of said tank ( 11 ).

25. The off-road competition motorcycle as set forth in claim 24 further comprising an air box ( 25 ), disposed between the top of said tank ( 11 ) and a handlebar header pipe ( 6 ) of said tubular trellis frame ( 5 ) in a portion ( 23 ) between side covers ( 24 ) of said tubular trellis frame ( 5 ), and beneath a seat ( 12 ) of said motorcycle ( 1 ).

26. The off-road competition motorcycle as set forth in claim 25 further comprising an engine breather located in a side wall of said air box ( 25 ), said engine breather ( 30 ) fluidly communicating with said air box ( 25 ) and a cylinder head ( 32 ) of said engine ( 2 ), and having a housing arranged substantially within a framework delta ( 29 ) of said tubular trellis frame ( 5 ).