Remember the old saying about estimating the time and doubling it to come up with something reasonable. A complete bike restoration can take several months to years. It’s probably going to take more time for several reasons. Most likely you'd be fitting the work around other things happening in your life, expect lots of interruptions and delays. You tend to discover parts that need replacement as the project is proceeding. Sometimes parts need to be sent away for servicing or they might not be readily available and you have to find them. Then there is the money thing. What level of perfection do I want, and how much is it going to cost. It always takes longer and cost more than you think
Teardown. Having a bike broken down into five hundred pieces at the end of the day can give one a terrific sense of accomplishment. Don't do it!. Putting everything back the right way and in the right place is the hard part. Here are some suggestions that might help.
1) The time between the teardown stage and assembly will take a while. Knowing exactly where things belong at some point in the distant future can save you an enormous amount of time. Invest in a selection of different sized freezer bags that have the nifty seals and a place for writing a label. As a part comes off, clean it with its respective fasteners, washers, gaskets etc. Put the pieces into a bag and label what it is and where it goes. Apart from left, right, front and back some things like carburetors, pistons and valves require referencing to the cylinder numbers. The plastic bags also protect the parts from corrosion. Spending extra time staying organized at this stage will have a huge payback six months from now when assembly starts.
2) Set parts aside that require further repairs or refinishing before assembly. Sometimes it's nice to have a few jobs that can be completed in an hour or so.
3) Follow the shop manual as you take things apart. If your not sure where to start or how things work, the manual will tell you. If you have a digital camera take lots of pictures especially areas that look complicated.
4) Invest in good tools. Fortunately you don’t need a lot of tools to work on a bike. A must is a set of 6 point sockets(not 12 point)in ¼’and 3/8” drives and a good selection of extensions. Universals and wobble extensions are handy to have for tight spaces. A set of hex sockets for ¼” drive are also a must have. For assembly you need a torque wrench. The newer types that go “click” are slick. Combination, box and open end wrenches, use them where you have to, but make sure they are in good shape. Hopefully Philip head screws will be a thing of the past some day, but until they are an impact driver is the best way to get them out.
5) Avoid damaging or breaking parts. A broken bolt may use up your valuable time attempting to remove it, or worse, destroying the part your working on. Parts for older bikes are expensive and hard to find. You just have to walk around a salvage yard to see bikes that have been scrapped because the parts needed for repairs are too expensive or not available. Not sure how to remove a rusty bolt with the stripped head. Here is practical advice from someone with years of experience on all aspects of MC repair See Dan's advice
6) Bikes built since the early 1980’s have lots of plastic and rubber components. These tend to become more fragile with age. So be careful.
6) If you don't have the special service tools specified in the manual. Make sure what you do use as a substitute will work without causing damage.
7) If you are fortunate enough to be working with a bike that runs. Test as many systems as possible before hand to identify problems and determine which parts need to be replaced or repaired.
8) If you’re uncertain about a procedure, the Nighthawk Groups in the links section are always very helpful.
9) Start looking for replacement parts as soon as possible even if your not buying right away just to get an idea what is available. Ebay and the various online groups are good sources as well as MC salvage yards. Parts for items that wear out, tend to still be available from Honda or other aftermarket supplier.
10) Don't get overwhelmed with the job. Break it down into smaller steps, each with a beginning and a finished end.
11) Gas tanks seem to get more easily damaged off the bike than on. Store them in a safe place, preferably far away from your work area.
12) You don't like wrenching on motorcycles but want a cheap bike, don't even start.
Stripped an internal thread here is how to fix it Using a Helocoil insert
1985 750 Nighthawk S
If your complete restoration of the bike includes major engine work,I would suggest the following teardown order to make engine removal as painless as possible.. 1) Seat 2) Gas tank 3) Exhaust pipes, 4) Rear tire 5) Air box with boots. 6) Engine.
Ref 5-2 Remove both ends of the hoses and look out for the O rings
Ref 5-4 Subframes (are these on 750SC’s also?)
Ref 5-4 Remove and examine gear shift position switch check for continuity. Ref 21-8
Ref 5-5 (Top) Engine Removal. The manual makes this job sound like a Sunday stroll.
If you’re planning to take the carbs off, this is a great time to do it and make a little extra room to squeeze the engine out of the right side. If you happen to be on the Olympic weightlifting team follow the manual. . If not, here is what works.
Save the frame paint, wrap it with some thin padding along the bottom right cradle tube where the oil pan has to clear. To have good control, you need to pull from the top, not push from the bottom as the manual suggests. To do this, locate the bike under a ceiling joist or roof rafter. Attach a light chain or rope hoist at a point above the engine to the joist. On the bike remove the two outside acorn nuts from each side of the head and make up two short straps from seatbelt material or a 1/16” X 1 1/4 steel strapping. Cut or drill two holes to suite the bolt spacing on the head in each strap. Attach the straps (use flat washers with the seat belt material). Next attach each end of a rope about 8 feet long to the straps in such a way as to make a bridle with the spine of the frame in the middle. Attach the bridle to the hoist and lift to take the full strain of the motor. Lift the motor just enough to make sure all of the engine mounts are free. Have a peek at the rubber boot at the driveshaft tube. It should just be starting to slide. Watch the boot for any pinching. Use the scissor jack under the oil pan to make tilting adjustments. The engine needs to go forward and as high as possible to clear the frame. To do this, lift up with the hoist and pull the bike back. The kickstand should slide on the floor. As you do, the spline connecting the output shaft from the motor to the universal joint should slide off. Look inside the rubber boot to make sure it has cleared before proceeding. Once the engine is in position, block it up and slide the bike sideways (left). When the strap on the left side of the head slides under spine of the frame, disconnect the rope and reattach to the strap, passing it under the right side of the spine. Pull the motor up a bit, continue sliding the bike to the left and the engine slips out. No strain, no pain and if your careful, not a scratch on the frame.