What are your front sprokets? Are they the stock? If so then at a 1:1 ratio at the output shafts your trike is geared to have more top speed then the bike. You have an 11% gearing advantage with the tires and sprockets all figured in to be exact. As far as the tires go, that 4"s accounts for 20% more surface area. Every 10 revolutions the bike makes, you'll be making 12. It makes a bigger difference then you would think. So you should be winning in top speed but the bike should be beating you in shorter drags according to the info provided.
'02 Honda 416ex - A seasoned blend of 11 herbs and spices
'04 Honda Recon - The yard machine and snow plow
'88 Honda CR250R - Another chapter in my torrid all terrain affair