Don't you know aboot the 5 HP gain from dropping the speedo drive?
Pull it, it won't be a problem later to put a new one in if you must have one. They sell replacements don't they?
You can always use a GPS to gauge your speed or just calculate your own speed in your head based on the tach

and the gear you're in and your tire size.
You can do a search on this too.
Just make sure you search the garage.
Not the sandbox.