Cannondaleriders

Have a small water leak coming from the top around where the water impeller is, havent taken the platic off yet just thought someone might now what it might be before i tare it appart?

Could be from two places,water pump cover or water pump seal, if its the seal you'll see water out of the little weep hole under the head. Or it could even be your bleader hole leaking. Either way make sure you know were its comeing from before you take it apart.

what is there into changing the water pump seal, do i have to drop the motor, or can i change it with the motor in it

You can change it with motor in.Is kind of a pain but quicker than motor removal.What I did was drill a small hole into old seal being careful to just go through seal no further.Tape or sleeve on drill helps that.Then screwed a drywall screw into the hole and using a pliers yanked the seal out by grabing screw.New one I just put grease in cavity and seal lips then silicone on edge of seal for lube.Found right size socket to use as a driver and it went right in.

so i just need to take the cover off and take the impeler off and the seal is behind there.

yes , but only the first seal is coolant there are actually two seals on the cam the inner is the oil seal, outer is water pump give me a call if i can help.
rich