Author Topic: CB 650sc Nighthawk survivor bike rebuild - Image heavy.  (Read 1789 times)

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Offline RJ CB450

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CB 650sc Nighthawk survivor bike rebuild - Image heavy.
« on: September 29, 2013, 09:03:27 PM »
First off, I tried posting earlier, and it said already posted but never showed.  So if I missed it showing up, or there is a delay, my apologies.

Hi guys, signed up to the forums a while back, but never posted.  Was too busy with this little story starting in July.  Picks don't show everything, but there is alot more done than what just the pictures will show.  Three months of solid work on it from buried in a shed for decades to riding again the morning of a charity toy ride.

I could write lots more, but will let the pictures tell the story and just ask if you have questions about any part of it.  To sum up, only things not rebuilt are the seat and bottom end of engine.  Over winter, I plan on restoring the emblems and panels/tank.  I will need to replace cam and followers as well, they got some grooves in them.





























« Last Edit: September 29, 2013, 09:14:47 PM by RJ CB450 »
74 CB450 K7 Supersport, 82 CB650sc Nighthawk, 1982 CBX 1000, 2015 Tiger XCx.... And some ol minibike with a 5hp Briggs.

Offline cb650

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Re: CB 650sc Nighthawk survivor bike rebuild - Image heavy.
« Reply #1 on: September 30, 2013, 02:46:29 AM »
Very nice.  Take care of the tank and sidecovers.  Very hard to find.
18 grand and 18 miles dont make you a biker

Offline RJ CB450

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Re: CB 650sc Nighthawk survivor bike rebuild - Image heavy.
« Reply #2 on: September 30, 2013, 09:05:25 AM »
Well, that is one of the issues, and a reason that it is in projects.  bike in general is in pretty rough asthetic condition.  Rust and scrapes everywhere.  Once the show falls, those skins are coming off and I will be getting exact replica decals re-created then a proper new shot of the pearl black.  The tank will have to be done before it starts to rust through on the bottom lip.  Side panels already had the busted tabs.  I used automotive trim panel clips and ultra high strength epoxy to put new ones in, but one shifted while curing so will need to remove and re-do this winter as well.

I didn't have time yesterday to list all the work but will put this up so others who are looking at reviving an old bike can know what to expect.   I enjoy reviving old things so had budgeted the literal thousands it would take just to get it ridable.  I have a friend who thought it would be easy until I had read off this list to him.  Also more time was spent just cleaning than actual mechanical work.  The residue left from ten year old fuel, brake fluid and fork gunk took alot of time just to clean out.

1.  Converted factory weld-on muffler pipes to accept slip on style mufflers.  This actually served two functions.  First, i was able to maintain the vintage look.  Second, it actually cost less in terms of dollars than the much more common MAC 4-2 or 4-1 style.  In terms of effort, took a whole weekend to properly prep and finish those header pipes.

2.  Four new mufflers. For now they are slash.
 
3. Front axle seals.

4. Rear seals not replaced yet under recommendation from honda.  Retainer ring was peened so need replacement before removing.

5.  Front and rear tires.

6.  Drive sprockets and chains.

7.  Full forks rebuild including seals, slide bushings, clips, washer and o-rings.

8.  Full caliper rebuilds using new honda parts.

9.  Complete stainless brake line assembly from HEL performance.

10.  Full brake master cylinder rebuild including new reservior.
*** important for first timers*** clean, clean and clean the master cylinder again.  Then when out riding, carry a piece of fine wire, philips screw driver for cover and wrench for bleed screw.  Also don't put on new rotors or pads.  I am not doing pads and rotors until winter cause of this reason below.

In master cylinder, there is a tiny return hole to allow excess brake pressure to release when you let off brake handle.  I was doing my test ride, and a little gunk from somewhere got shifted and blocked it up again.  Stuck my front brakes on, and I cooked my rotors and pads clearing out of traffic.  Used wrench to bleed off pressure allowing me to get to a safer spot to work, then used wire to unblock passage.  I never ride without a trusty adjustable wrench.

11.  Professional cylinder head rebuild and machining.

12.  High strength stainless steel plug inserts for all four cylinders.  Design of head resulting in deep corrosion.  Enough to sieze two plugs in permanently.

13.  Full carburetor assembly rebuild.

14.  All new lines and hoses including the T vents between carbs.  These T-vents are very important.  Have the carbs apart, spend the money for new ones from honda.

15.  New petcock from honda.  Unusual size limits aftermarket availability.  Old one had damage, leaked, etc.  Was repaired in past poorly.  Not worth attempting to rebuild original.

16.  Full chemical liner and rust neutralizer of inside of tank.

17.  Air box assembly clean and rebuild.  restoration of rubber components.

18.  ***Repair to handlebar throttle***
        This is only plastic clamped to chrome and was worn.  There was not enough material to provide enough force to keep it from rotating with the throttle.  Solution was I wrapped the clamp location in a water resistant emery cloth to provide a solid bite.  Will re-evaluate and look at other possible solutions if necessary.

19.  Battery replacement and electrical inspection.

20.  ***Clutch cable repair and adjustment***
       Clutch cable was siezed with dirt due to improperly installed bellow at clutch plate linkage.  A previous "mechanic" had the clutch adjustments so out of wack to make it work, it would slip at anything more than slight throttle.  I removed, cleaned and repaired to the best of my abilities the cables and got clutch working okay

That was all just to get it mechanically rideable and probably missed at least a few little things.  Things still to do to ensure it stays that way.

1.  New pads, shoes and rotors.

2.  Service clutch pack.

3.  Replace clutch cable assembly.

4.  Fine tune carburetors.

5.  Re-aupholster seat.  Seams are letting go and really won't hold up much longer.  I am thinking of tracking down a new pan if possible to keep old.

6.  Replace camshaft and followers.

7.  Replace coils and plug wires.

8.  Repaint and re-decal skins to prevent further degredation.
74 CB450 K7 Supersport, 82 CB650sc Nighthawk, 1982 CBX 1000, 2015 Tiger XCx.... And some ol minibike with a 5hp Briggs.

Offline RJ CB450

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Re: CB 650sc Nighthawk survivor bike rebuild - Image heavy.
« Reply #3 on: May 30, 2014, 11:04:15 PM »
Bump up from last fall and returning to this forum to show new work and progress.

For the most part this year, it has been some standard work.  I started with cables and brakes.



So add to the above list, new cabling, and EBC rotors and pads, the good stuff, no jobber replacements here.  Just to give an idea of the cost of this part of the project, one of those rotors cost more than I paid for the bike...  Worth the money.  Brakes grab so hard that when I am at a complete stop, the rear can be held a couple of inches with the suspension unloaded if I have to do a hard emergency stop.  With this kind of braking power upgrade, it definitely exceed OEM design, and I am glad I went for the good stuff for the meats!

After all that, came the winter waiting....

Soon....



And not long after, it was a balmy 5 degrees celsius outside, and the roads had cleared enough for riding (despite there still being snowbanks a metre high still) but before I could ride, the bike needed some final heavy medical rehab to get on the road properly!



Man, I need to find the charger for my camera and get some audio of the bike now.  For the past month, been tweaks to fuel, and a re-syncing.  Aside from a slight roughness at 3500 with minimum throttle, it sings like a symphony.  Remember, this is humming smooth tuned with a machined head (had to as part of head repair) and running quad glasspacks.  Easter weekend, I vowed to go for a ride to pick up some new novels, then head over to Fatburger which had just opened up in my area.  You cannot tell by the pic, but it was 7 celsius that day, and less than an hour before was rain.  I took this pic cause she be all dirty....



The sound and power is phenomenal, and she will rev past the 9k on a first gear launch faster than you can shift.  I can hardly believe is the same bike, or that it is a +40 year old engine design.  I was bad and took it onto an open stretch of smooth blacktop.  No fairings, and will gear out in top gear.  She does the ton no problem now and on stock ratios, but little bit of wind buffet for the rider....

No pics of it uploaded, but couple weeks ago, full charging system rebuild.  Rotor was going, so I replaced it along with stator and rectifier.  Keeping originals of course, just in case.

Next up is some minor work for the summer with new clutch plates and progressive rear suspension for the rear.  Is actually quite the ride.  I like it more for "spirited" riding than my buddy's 636 ninja.
« Last Edit: May 30, 2014, 11:06:13 PM by RJ CB450 »
74 CB450 K7 Supersport, 82 CB650sc Nighthawk, 1982 CBX 1000, 2015 Tiger XCx.... And some ol minibike with a 5hp Briggs.