Stage6 crank oil/waterpump gearwheel problem

[pr0ve]

I bought a stage6 crank and I have some problems... How should the gearwheel that runs the water/oilpump be fasten on the crank? It has a "flat" inner side and the crank is also flat and to me it says that it wont spin very much! So how should this gearwheel be fasten?
Is my crank deformed or something?!? Couse on all the pics i've seen the crank gets a bigger diameter were this gearwheel should be fasten. Maybe I should ad that it was bent when I got it and had to straight it out.
Any ideas?
thanks!

Ouups, forgot to tell, piaggio ofcourse!

 

[Eoin70]

there should be a small hole in the crank which a pin fits into and then the hole in the plastic gear fits onto it

 

[Mexicano]

Pr0ve:

This pic is from an AC minarrelli but will show you what Eoin70 is telling you, I hope it helps!

http://img242.echo.cx/my.php?image=dsc024544at.jpg

 

[Eoin70]

oh no i tthink this guy is on piaggio

 

[Mexicano]

O.K. but maybe he got the idea, isn't it?