Figure on most of a day. You'll find it a LOT easier if you have a motorcycle jack to help lift and jockey the engine out. I wouldn't start on it unless I had a good service manual, preferably the Honda manual available from Helm Inc. or the Clymer book.
I have a floor jack and a ride on lift, I am going to pull the alternator and check the shaft coupling and rubber drive bushings before I attempt the engine removal. There was some question about the mechanics diagnoses of the clattering when the engine is cold.
Sure can! When the engine is first started there is a loud clanking (rattling) noise, the noise semi disappears after the engine has been running for several min. the engine runs great and has plenty of power, the engine has 43,000 miles. I carried it to the local Honda dealer and their mechanic said he spent 6 1/2 hours trying to find the culprit of the noise, he then determined it was the alternator drive shaft, I was charged for half the time spent @$85.00 per hr. I was told the noise was not there when he pulled the alternator and ran the engine, and to solve the problem the engine would need pulling to get the shaft out.
Service manual, paint pens, about 12 feet of clean tables, if you could borrow a jack with a wider platform you will be glad, digital camera (you cannot take too many pictures), long curved and 90 degree needle nose pliers, ratchet wrenches are real handy, a cheap organizer with plastic drawers works well to keep bolts sorted, use paint pens to mark all hoses and fittings. I'm sure I'll think of some more later.
I use zip lock baggies. Get a box each of several different sizes up to the quart size. you can label them with where the parts came from which can help a lot with the reinstallation. One thing you might be able to do is to put some drag on the engine side coupler with a gloved hand and crank the engine with the sparkplugs out to see if you can cause the noise or feel any slop. If there's something going bad with the shaft I'd think there'd have to be a fair amount of free play for it to make noise. One other possibility would be the noise coming from the alternator itself. Unlikely but possible, and that would explain why the noise went away with the alternator removed. Some of the later year 1500s did have problems with the alternator bearings. I think it was the small bearing going bad. If it got bad enough it could even get loose in the bearing pocket. So the first thing I'd check on your bike would be for free play on the engine end coupler and if that felt okay, tear down the alternator and check it's bearings and look at the rotor for any sign that something got loose in the alternator case.
I have the jacks, tools, shop and camera, the paint sticks I am not a owner of. I change and balance my own tires, I have never had a need to work on any of the Gold Wings I have owned before this one. I thought several years ago I was retiring from working on anything, now this has taken place.
It has a Compu-fire alternator, I was told by the same mechanic that the heavy duty alternators can cause this problem because they put a lot of extra strain on the shaft, I have not a clue either way, if it can or cannot.
I will remove the alternator and check the drive coupling for slack, I will go back with new damper rubbers, I had rather spend $35.00 first before pulling the engine. The Honda mechanic said there was nothing wrong with coupling or damper rubbers, I will know for sure in a few days.