If you had just had a motor replacement I would suggest checking the motor alignment in the frame via the stabilizers, but what you are discribing can only be the front motor mount in a bike where the motor has never been removed. The mounts tear but with the motor off and sitting still, you can't see the tear because the weight of the motor compresses it. This is not a hard fix. Go buy a new mount at your local dealer and if you don't have one already, a shop manual and also a parts manual. I always tell my frends to get the parts manual, because it has exploded diagrams of everything and you know sometimes a pictures worth a thousand words. So find the section in the shop manual that covers the motor mount and check the parts manual on the section where the frame is shown. The change out should go something like this. Unplug the voltage regulator and get that out of the way, Also, unbolt your oil cooler and let it hang down below the mount on the hoses. Unbolt your old motor mount and then place somthing under the motor (a scissors jack would be great) so it doesn't drop down when you remove the old mount. With the old mount out, just to be sure, put the metal part of it in a vice, clamp it down and stick a big screw driver through the hole in the rubber. Twist the rubber around a bit and the tear should appear. Repalce the old mount with the new one and reverse the steps above. That should do it Oh yeah, one other thing. Be patient, take your time, don't stress out. It isn't rocket science. Above all, don't try to rush.