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Repair Tips

Have a repair tip you want to share? Shoot me a note here!
You'll find that if that 650 has been well cared for, there are no specific problems to worry about. The charging systems are not necessarily problematic if you understand their limitations. They WILL NOT CHARGE at idle; the battery actually discharges at a rate of about 10 amps at idle. "Break Even" is at around 2000 RPM, and above 2500 you're charging. And that's the spec, so that's just the way it is. Most of us use battery tenders to keep the batteries at peak charge when we're not riding.


Other than that, the only known issue that might be worth reporting is that the cam chain tensioner spring tends to lose some of its tension, allowing some cam chain noise after a while. I don't know anyone who's actually had one come apart, but I guess it can get pretty irritating. My 650's got around 23,000 on it with no issues (and it was really abused before I got it, for the first 11k).

Ben
'83 650SC
Grand Blanc, MI

  • Malfunctioning Neutral Light on Nighthawk 650 
Note: The following question and response was taken from a Honda Nighthawk discussion group. It was a reply to someone desiring repair help on a Nighthawk 650.

QUESTION:
I just purchased a 1983 CB650SC Nighthawk. I like the bike, but not its neutral indicator light. Not only does the light come on when the bike is shifted into neutral, but it also comes on when the clutch is engaged in any gear! Quite maddening! How can I get the indicator to come on only when I shift into neutral?

Rider in Boise, Idaho

RESPONSE:
Just last week we just solved this exact problem on someone else's NH. The cause is either the diode (Honda calls it a silicon rectifier) or the wires that go to it. You will probably need to replace the diode, which is a small black box that plugs into a two-wire plug beneath the seat / tank junction on the right side, or inside the right side cover. You will need a continuity tester, such as a VOM.

Reid
'84 CB700SC

'99 Ducati ST4
 


  • Tip For Cleaning a Rusty Area - 
A neat thing someone suggested to me many moons ago that works great on small areas where you would like to hit it with a wire brush before repainting or lubing, is to get a wire brush used for cleaning a small caliper firearm, like the wire brush for cleaning a .22 cal rifle.
    Put the cleaning brush in a drill and it makes a great little high speed wire brush for cleaning very small areas.
      Can also be great for corroded electronics that need a good cleaning to make electrical contacts work again.
      • Here's an Electrical fault finding chart in Adobe Acrobat Format specifically designed for motorcycle charging systems. It includes guidance for checking and improving not only your battery ground, but the ground for your regulator/rectifier.
      • Shop Manuals [The following tips were sent to me from David Kirk.]
      Buying a Honda Shop Manual is a great idea. I am waiting for mine to arrive from www.helminc.com. Good prices, and you can get owners manuals, etc. there as well. You can also get a pdf of the Honda Common Service Manual at this link which is very handy.
        Thanks for the tips David! 
        • Engine cleaning tips
        Just wanted to share one of my engine cleaning secrets that I used on the 4x4 when I would go mudding. I can't believe I didn't think of this for on the bike before now. I use to have an 89 Toyota 4x4 that I took mudding all the time. When I wanted to clean it up I would use STP Tire Foam and spray the entire engine and chassis. It would dissolve any grease and the dirt and mud from my 4 wheeling and leave everything spotless. I was thinking I needed to get some more to clean the car when I thought, duh, use it on the bike. Man, I hate washing the bike and trying to get into all the areas with the engine exposed and all, so I just sprayed down the engine, drive shaft and wheels, which are a real pain to keep clean with that textured black paint. Not only did it dissolve all the grease and grime and leave the engine shiny black, but also gives all the wires a beautiful just armor-alled look. Of course you must be careful of the wiring and especially the plugs, but this trick works great. Do be careful though and DO NOT get it on the tread of the tires or they will be slick as you know what. I just let it sit for a while, then polished the fender and pipes, put a fresh coat of wax on the tank and the bike looks great.
          When I use to do this to the truck, it had 98,000 miles of grime on it when I purchased it. I totaled the truck at 125,000 miles and the insurance company gave me an extra $1800 over book value because it was so clean. They sent me a list with my payoff check of everything, $250 - engine extra clean, $150-transmission extra clean $150-drive-train and chassis extra clean, etc.
            Do not do this in the garage like I stupidly did. The foam will dissolve the grease and drip all over the floor. Then you will have to run your tires through it when pulling out of the garage making sections of the tires very slippery. After the foam dissolves, it is basically the same thing as Armor-All.
              Mike 83 NH CB550SC
              • Tip on modifying your stock seat 
              For those who don't want to buy a Corbin you can simply remove the seat cover stapled underneath the seat with about .5 inch overlaps, remove the OEM masochistic padding, put your own increased padding and then instead of overlapping the cover under the seat, simply take it to the edge of the plastic seat bucket and attach with silver or gold rivets or prongs with holes drilled through the plastic bucket. This allow much more padding and I think looks better. You no longer have the passenger bump and can sit as far back as you want. You can keep or leave off the strap. My padding of almost two pillows worth will sag over the sides as I sit making for a widder seat but doesn't appear saggy when not ridding. It does increase rider height. I've gone from an under 50 mile rider to twice that comfortably. You can adjust the handlebars a little to accomodate change. Safe and comfortable riding all.
                Pat from Peoria, IL
                2002 Nighthawk 750
                • Service Bulletin for 1982 CB or CM 450 regarding carb issues 
                If you have an '82 CB450 or CM450 and you've been experiencing carburetor problems, check out the following Honda service bulletin (You must have the FREE Adobe Reader to access this file.) Also here is an image of an article written about the 450 carburetor problem, then an image of the carburetor jet needles, and finally a Word file containing a link for Honda Nighthawk Carburetor Float Bowl gaskets, along with a photo of the gaskets.
                  Contributed by Jennifer J.
                  • Winterizing Tips for your Motorcycle 
                  1) Oil your chain.
                    2) Fill up your gas tank and add sta-bil or some similar product. Take the bike out for a spin for about 10 minutes and let the sta-bil mix with the gas and get into the carburetor bowl. Turn the petcock to off. You can drain the bowls, but with stabilized gas in them, there is not really a need. Make sure the tank is quite full to prevent condensation from forming inside and causing rust.
                      3) All gasoline engines should be fogged prior to storage for a period longer than 30 days. If your bike will run with the air filter out, spray fogging oil into the airbox until the engine dies. That will get the oil in the cylinders really well, also into the manifolds (unless they're rubber on your model?) Another way of doing that is to take out the plugs and fog each cylinder while cranking the engine over a few times. That may be preferable. Put the plugs back in.
                        4) Change the oil. Don't leave the old oil in over the winter. It is good to change the filter every other oil change.
                          5) Take the battery out and make sure it is filled properly with distilled water. Take it inside out of the elements and put it on the battery tender junior, or charge every 2 weeks. It's fine to leave it in a cool area, which will slow down the discharge rate.
                            6) Put the bike on its center stand.
                              7) Clean and wax the painted parts.
                                8) Spray any parts that could rust with KEL or some other protectorate since you will most likely be storing outside where humidity, as well as sweating or condensation could cause rust.
                                  9) Clean the windshield and use Plexus, or some other Lucite/acrylic safe product. No ammonia and no paper towels.
                                    10) Use NuVinyl, or some other product that is okay for rubber on all the rubber and vinyl parts. Don't use ArmourAll, as it makes rubber brittle.
                                      Written by Jennifer J
                                      • Brake Purging 101 
                                      Do be careful about getting brake fluid on your tank. Keep the tank well covered. That Valvoline synthetic brake fluid is real good (in a golden container). It is a little more expensive than the regular junk but is very good stuff.

                                      Taking off the reservoir cover...be careful the screws have a tendency to stick. Get the right size phillips screwdriver. If you don't have any anti-seize compound, get some. Motorcycles are famous for siezed fasteners. Steel screws in aluminum threads mean seized (dissimilar metals make a battery and electrons flow causing oxidation.)

                                      Checking brake fluid and replacing it are two different things. Brake fluid MUST be replaced regularly (I replace all the fluids brake/clutch once a year). Brake fluid absorbs moisture from the air and gets contaminated. It causes rust in the calipers and that is what causes the sticking and hard-to-press brakes.

                                      The way I do my replacement of fluid is:

                                      1) Cover the tank with plastic and then a cloth. Take a look at your front fender. It may be prone to getting a drip.
                                      2) Remove the brake (or clutch) reservoir
                                      3) With your Mighty Vac suck the reservoir ALMOST dry
                                      4) Fill with fresh brake fluid
                                      5) Remove dust cover from caliper bleed screw
                                      6) Place a box-end wrench on screw (6mm or 8mm)
                                      7) Place Mighty Vac hose on bleed screw end with adapters (if necessary)
                                      8) Pull a vacuum with the Mighty Vac
                                      9) Slowly loosen the bleed screw until brake fluid starts flowing
                                      10) Keep the vacuum going and watch the reservoir
                                      11) When the reservoir gets almost empty, shut the bleed screw off and add more fluid to the reservoir
                                      12) Keep doing that until the fluid looks as clear as what went into the reservoir
                                      13) Resume your Mighty Vac removal (steps 8 thru 11)
                                      14) I would do this a couple of times and then see if the procedure has helped. It may take a couple of times but the problems should start going away if it is not completely jammed.

                                      My Nighthawk had about 9000 miles on it when I got it about 8 years ago. The front brakes felt strange when I got it. I did basically what I described above. Brake fluid came out originally looking like Coca-Cola instead of water. I replaced the fluid 6 months later and it was a little dark but much better. I replaced it again 6 months and it was barely dark. I have been changing once a year when cold crappy weather is here. About 3 years ago I discovered the Valvoline synthetic and now the fluid looks the same (I pull 3 reservoirs for each caliper to make sure). Today my Nighthawk as 48,000 miles on it and the brakes are just fine.

                                      Contributed by Ben Kirk
                                      Click here for more on maintaining fork seals
                                      • Removing Broken Exhaust Studs 
                                      I've had a couple of broken exhaust studs on my bike since I've owned it (about a year). I finally got around to buying new studs and attempting to replace them. Well long story short, vice grips suck for this job. After rounding off one so that it was no longer possible to get any grip at all and watching my friend break off another, frustration (and pain) set in and we had to call it a night. I went out to Sears and bought a stud extractor kit (Sears item #00946338000). This, coupled with some super-duper spray lubricant turned out to be the best $36 ever spent on the bike. If you have exhaust studs that you will be replacing, I highly recommend using the right tool for the job and these are definitely what the doctor ordered.

                                      [PA]
                                      '85 CB700SC
                                      Omaha, NE USA


                                      (Written by P. Allen and taken from an online discussion group)
                                      Carburetor Tutorials (Adobe Acrobat format)
                                      • Making adjustments on Cam Chain Tensioner and Acceleration Pump
                                      • I found a substantial improvement in the sound of the top end of the motor after taking two minutes to loosen up (then retighten) the self adjusting cam chain tensioner and let it do its thing. Before this adjustment I was getting a rattling/loose sound from the top end at about ~4300 rpm. The sound is now totally gone. I have also pulled the carbs and found the acceleration pump was mal-adjusted and was not doing its job at all. After the fix (parts available on eBay for less than $20), I now see four nice little spurts of fuel down through each of the four carbs whenever the throttle is whipped open (the design here is to keep the fuel/air mixture from becoming momentarily too lean when the throttle plate is suddenly opened). With this repair, I hope to see an even better throttle response now when I get it back together. Maintenance Tip sent to me from Paul Devlin, Ottawa, Canada
                                        [Further note on Cam Chain Tensioner: The cam chain tensioner on the '83-'85 650 is not manually adjustable. It's spring-loaded and either the spring can lose tension or the slipper can wear out. Repair involves replacement of the offending part and requires removal of the valve covers. The sound of a loose cam chain, as I've recently been told, occurs at lower rpm and is most noticeable when the throttle is snapped shut. Sounds like ball bearings being rolled around in a can. Additional Tip from Dave, taken from Honda Nighthawk email group.]
                                      • Dealing with Sudden Headlight Loss
                                      • One day my headlight gave up the ghost out of the blue. Nothing else was malfunctioning. After checking all wiring (as much as possible) and of course the bulb itself, I discovered the problem within the right handle bar "starter" housing. When you push the starter button the headlight is supposed to dim for that moment while the engine is cranking. In the housing is a soldered wire that had come loose. After soldering it back, the headlight worked like new again. I didn't even have to take it off the handlebar! Hope this helps for some other person with sudden "light loss." Maintenance Tip sent to me from John Vanveen, St. Albert, Canada
                                      • Motorcycle Tire Changing
                                      • Here's a great HOW-TO site for those willing to tackle tire changing on your motorcycle. Maintenance Tip taken from the Honda Nighthawk email group on Yahoogroups
                                      • Various Tips
                                      I would like to offer my success stories for all of you to benefit from.

                                      #1 - Online shopping -
                                      For OEM and aftermerket parts. I highly reccommend http://www.bikebandit.com/ simple easy to use web page, find the smallest parts you need. They have excellent prices and ship very safely/quickly. I have also had excellent luck on eBay.

                                      #2 - Rust -
                                      I have an older friend who has been into boats for 50+ years. We all know what saltwater can do to metal, especially chrome....hmmm maybe those boats guys know some things us bike guys can benefit from, eh? I have been doing rust repairs since.. well.. since I got my first car "laugh with me, not at me." Anyway rust is like a disease. I have found there are 3 kinds of rust: surface, pitted, and complete.

                                      Surface rust is basically tarnish. The metal is still complete and smooth, just hidden under an oxidized layer. This is basically what boats get constantly. I was introduced to a product called "Nevr-Dull" available at any marine store, or ACE hardware. This stuff is absolute magic. You need only a rag and a can of this. It comes as cotton soaked in...um..the magic stuff.. it takes some elbow grease you gotta work a small section at a time. But this stuff WILL amaze you.. Even border-line pitted metal will become almost new with this stuff. Its about 5 bucks for a can and you can do your whole bike easily. Leaves a super protective coat on the fresh metal. Great for any unpainted metal. Especially Chrome/ polished.

                                      Pitted rust is where you can still see the original metal but the rust has eaten into it. My advise, same as the other guy who advised using a wire brush. You can get all shapes and sizes to fit your needs. I use a 2 inch wheel in a small 9V drill. It worked extremely well. Note: by using an abrasive, chrome will not look the same, it will have a different shine, unless you really spend time downgrading the abrasive and polishing. Sometimes you can do a combination of Nevr-Dull and the abrasive method, so as to do as little wire brushing as possible. Also when done use the Nevr-Dull to coat the newly exposed metal or it'll flash rust in a few days. Great for any unpainted metal.

                                      Complete rust where the metal flakes off in your hand is obviously the worst kind. **Usually requires cutting out effected area, then either fiber-glassing or welding new metal as a replacement. I have done both. Either is a tedious and frustrating job. Both are costly too, depending on how big the area is. If you can do the fiberglass, you will have better results as a DIYer (do-it-yourselfer) and small fixes are easy and cheap especially dealing with plastic fairings. Welding is always my last choice. Its not easy to do, and a shop will charge a bunch as most bikes have many aluminum parts which are very difficult to weld.

                                      **Even if the metal is flaking off, sometimes if there is enough integrity left in the metal, and if its not a working part, you can buy Naval Jelly (Home Depot, Auto Parts) a pink, snot-like, acid that dissolves rust. It works pretty good if you are going to paint over it.

                                      #3 - for those of you with the newer nighthawk 750s, (91+) check out this page: - http://www.nighthawk750.com/index.shtml under MODIFICATIONS. I totally recommend the carb needle washer mod and the Tim Hodge mod. They are easy to do and cost less than 20 bucks. Both have significantly improved the overall performance of my bike. I can start the bike with the choke and after 20 seconds be on my way without that notorious "Honda hesitation," or 5 minute warm-up. The bike actually gets better gas mileage now. 165 before reserve.

                                      The above tips were sent to me by Steven Peto from New Jersey, owner of a 1993 Nighthawk 750. 
                                      • Is your windshield too tall?
                                      Before you give up on this excellent windscreen you might want to consider cutting it down. It's easy to do especially if you have access to a band saw, but if you are careful, you can use other tools with a blade for cutting plastic. Here's how:

                                      Sit on the bike and put your finger on it where visually it would be good for you... then, put some electrical tape across it, and ride for a while and move the tape up or down until it is where you want it..... keep in mind, you can cut more off, but you can't glue it back on....

                                      Then put several layers of masking tape on the top 5-6 inches (both sides).Use a kids compass, hooking the metal foot on the top and sliding it across making a pencil line on the masking tape. This gives the same curve across the top. The corners are done by eye, or use a 1/2 dollar coin. Take note of the angle of the edge as you will want to duplicate it later.

                                      Use a jig saw, router, rotozip, band saw or a hacksaw blade and cut it, on or off the bike (I cover the bike to keep the junk off it). Use a very fine toothed blade and go slow so the plastic doesn't get hot and melt. If you don't have the tools, or you are nervous about doing it, take it to your local plastics or cabinet shop.

                                      After cutting, sand the edges with some 80 grit sandpaper wrapped around a wooden block, then ride it for awhile. Repeat until it's where you want it. Then use 150 grit to get out the 80 grit marks and then some 220 to remove the 150 marks. Try to match the original edge angle.

                                      Jon
                                      92 NH 750
                                      Taken from the archive of a Honda Nighthawks Email group

                                      • Removing the Seat on the Nighthawk 250 
                                      If you purchased a Nighthawk 250 and weren't given an Owner's Manual, chances are you're clueless on how to remove the seat. You have to insert the key into the helmet lock, turn clockwise, and when it opens, push down on a latch that is right under the key. Then you SLIDE the seat back, and there you will find . . . the owners manual!! :)
                                      • Headlight mod for the Nighthawk 250 
                                      Did this Conversion and It WORKS GREAT!!! The improvement over the
                                      incandescent bulb is like night and day. I used a Wal-mart sealed
                                      beam number H6024. Had to cut off the old mounting tabs like
                                      described, but the headlight is STUFFED into the outer ring , so it's
                                      not going anywhere. Had to shove it in, carefully, to the housing
                                      because it is thicker, but I got it in there.

                                      As for adjustment, you still have the up and down, but no side to
                                      side. The Halogen produces an extra wide beam, so that is not any
                                      problem either.

                                      For $9, this is probably the best mod I have done so far.

                                      Tip by Robert
                                      • Dealing with a motorcycle that is sputtering and hesitating 
                                      I found that when the motor began to sputter if I switched back and forth from primary to reserve a few times she began to act normally which diagnosed the problem as a petcock obstruction. Here's what I did to fix it. I took off the tank and flushed it w/gas to remove sediment. I then took the p.c. valve (off tank) and broke it down (except vacuum module) cleaning all screens. I sprayed carb cleaner in all ports then reassembled. I then hooked the mity-vac to the vacuum port and applied vacuum while spraying cleaner into fuel inlet until it ran clear. I then installed a new inline fuel filter and put everything back on the bike. "Precious" has been running like a champ since. The carb cleaner is the Valvoline SynPower.

                                      Tip by Michael A. 
                                      • Honda Charts for Tires, Chain, Sprocket, Battery and Plugs 
                                      Wondering about what size tires are stock for your bike, or which battery to get, or even which chain?? Check out this chart of stock Honda sizes for those things and more. Under 600cc | Over 600cc
                                      • How to set the timing on your motorcycle - CLICK HERE (slideshow) 
                                      • Wondering about cleaning your motorcycle chain? CLICK HERE for a great article 
                                      • Checklist for starting a bike that has been sitting a long time 
                                        • (Instructions claim to be for a GL1100 but these are great tips for any bike!) 
                                      • A fix for hairline cracks in the coil 
                                      My 84 cb700 decided it does not like wet weather. After several days and hours of spraying water on various areas I finally discovered my coils have stress cracks around the mounting tabs at each end. A co- worker told me his dad used finger nail polish on the coils of his antique john deer. I tried that but it seemed to flake off. I bought some of that new liquid electrical tape and applied it to the coils. WOW did it do a good job. I used a wire disk in a dremmel tool to rough up the surface area and the liquid electrical tape bonded really well. gave it an overnight drying time and re-installed the coils. Its been working great ever since. Bike bandit listed the new coils at $94 a piece (X 2).The coating cost me less than $8.

                                      --Contributed by Ty and taken from the Nighthawk Lovers Discussion Group 

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                                      If you have insights and experience on repair and maintenance issues that would benefit other Nighthawk owners, please join my Nighthawk Lovers email group and share with all of us, or shoot me a note here!

                                      Paul