Its cold here, especially today, and I was taking a work break to think about motorcycles - warm thoughts that pass the winter doldrums more pleasantly. 

So today I was thinking about MotoGP engines, and unfortunately I don't have a whole lot of information on what each manufacturer is or has been using recently, but with the addition of CRT and the Aprilia GP 'superbike', I thought I'd see if anyone else has any good technical information.

Ducati uses the desmosedici engine: V4, displacement formerly limited to 990cc and 800cc depending on rules. Well V4 motors make it into production, if not only on the Desmosedici, also on the Honda VFR, Aprilia RSV4, and forthcoming Motus (iirc).

Honda has used a V-5 in the 211 - but I've read its a V4 in later years.   I'm unaware of any showroom floor model ever equipped with a V-5.

Yamaha seems to use a more conventional I4 setup.  Not unlike their production machines, I suppose.


Here's just one of many links I perused: http://www.maclean-nj.com/2002motogpengines.htm


off to the coffee pot now, your turn.   

I think Dorna putting the rule of 81mm pistons has really put a damper on the series and it's motors

Imagine a short stroke Superquadrata as a CRT!

This will get you up to speed on what engines have been used recently and what is in use now:
http://en.wikipedia.org/wiki/Grand_Prix_motorcycle_racing

So was thinking about the 81mm bore limit and 4cyl limit. I think this was designed to keep the twins out of the competition.
imagine a superquadrata with the same 112mm bore with a 50.75 stroke.  a 2.21 ratio a supersuperquadrata!

# cyl = bore x stroke with 81mm bore limit  
2 cyl = 81mm x 97.03mm
3 cyl = 81mm x 64.68mm
4 cyl = 81mm x 48.51mm

Seems like with a bore-maximum prescribed, its advantageous to run as many cylinders as possible (within other design constraints obviously, such as weight distribution, width, frame design elements, etc)

Quote from: Speeddog on January 03, 2012, 08:43:38 AM
This will get you up to speed on what engines have been used recently and what is in use now:
http://en.wikipedia.org/wiki/Grand_Prix_motorcycle_racing

I had read that one - was hoping for some good layout diagrams of the various works-motors.

Quote from: Raux on January 03, 2012, 09:10:24 AM
So was thinking about the 81mm bore limit and 4cyl limit. I think this was designed to keep the twins out of the competition.
imagine a superquadrata with the same 112mm bore with a 50.75 stroke.  a 2.21 ratio a supersuperquadrata!

# cyl = bore x stroke with 81mm bore limit  
2 cyl = 81mm x 97.03mm
3 cyl = 81mm x 64.68mm
4 cyl = 81mm x 48.51mm

there hasn't been a twin in the series since the 2-stroke era even with the rules allowing them (with a significant weight advantage) in the 990 4-stroke era.