Author Topic: 1983 Nighthawk 550 resto (Read 7148 times)

Dnor72 · « **on:** April 10, 2017, 08:29:01 AM »

After finishing the CB350F I needed another project. I picked up this 1983 Honda Nighthawk 550 for $450. She is rough, but she does run, albeit very poorly. 47,000 miles, compression is low-ish 90-110-100-100, shoots up to 180 with a little oil added to the plug hole. Chrome is surprisingly decent, seat is okay, wheels are acceptable, brakes work, all electronics work. Gonna get her running right and then strip her down and bring her back.

Is the "Project Shop" the right place for this or should it be in the "Other Bikes" section?

Oh yah, those look nice.

And she runs

Dnor72 · « **Reply #1 on:** April 12, 2017, 08:58:31 AM »

Oil and filter change. What a PITA getting the oil bolt through the oil cooler and screwing it in. So simple, yet I kept thinking it was going in crooked and messing up the threads. Eventually got it in, shouldn't have been that difficult.

UPDATE: The oil filter I bought (Wix) was about 1/8" too tall and so the filter holder would not screw down all the way, hence the difficulty screwing it on. Got a different brand filter and it went right on no problem.

Also took the carbs off. Going to strip them down and clean them up while waiting on some rebuild kits. Aside from the throttle cable being attached way down inside the carb rack, these seem a little simpler overall than the ones on the CB350F. Rubber boots look good.

Dnor72 · « **Reply #2 on:** April 28, 2017, 07:17:20 AM »

Replaced the plugs, air filter and rebuilt the MC for the clutch (she shifts now).

Nice mouse nest in there

Cleaned the carbs and replaced all the rubber bits. These carbs had definitely never been separated before. Stripped most of the screws that keep them together and had to extract them. Replaced with OEM. Bench sync is pretty easy with these carbs.

Installed

Vac sync

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Dnor72 · « **Reply #3 on:** April 28, 2017, 07:19:28 AM »

Running not terrible. Cam chain/tensioner def needs some attention.

Dnor72 · « **Reply #4 on:** May 07, 2017, 07:19:07 PM »

Digging into the top end, to replace the cam chain tensioner, take a look at the valvetrain and re-ring the pistons.

Dnor72 · « **Reply #5 on:** May 11, 2017, 06:24:52 AM »

A couple of the exhaust valve seats could use a regrind, but that will have to wait until winter when I plan on dropping this off at the machine shop for a proper service. Cleaned everything up, checked tolerances, new valves stem seals, lapped the valves and she's going back together.

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Dnor72 · « **Reply #6 on:** May 12, 2017, 11:56:44 AM »

Valves back in place, head degreased, scuffed and painted. Valve cover polished.

Getting ready to ring the pistons and prep the cylinders.

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Dnor72 · « **Reply #7 on:** May 13, 2017, 03:55:16 PM »

Ring end gaps checked, bores in spec, honed. Just have to prep the jugs for paint and I can get this top end back together.

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Dnor72 · « **Reply #8 on:** May 19, 2017, 03:57:17 PM »

Decided to just continue with the strip down and finish the top end on the build up. Plus the engine is much easier to muscle around the garage sans jugs and head.

On the jack

Lump removed

PCd frame

Detailed engine

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Marks78 · « **Reply #9 on:** May 20, 2017, 08:14:07 AM »

Nice progress on the project Dnor72! Wish I could progress as quickly with mine. Keep up the good work and enjoy the ride!

Dnor72 · « **Reply #10 on:** May 20, 2017, 08:47:55 AM »

Quote from: Marks78 on May 20, 2017, 08:14:07 AM

Nice progress on the project Dnor72! Wish I could progress as quickly with mine. Keep up the good work and enjoy the ride!

Thanks Marks. I've had some time off recently and I've really been going at it. Only my second resto, but I'm 1% better at predicting what I'll need for parts so that I can get out in front of it. Waiting on parts takes so much time.

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Dnor72 · « **Reply #11 on:** May 23, 2017, 04:35:03 PM »

Got the engine in the PCd frame, started wiring it up.

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Dnor72 · « **Reply #12 on:** May 26, 2017, 07:56:24 PM »

Everything but the brake lights and rear winkers wired. Put the battery in and the stuff in the front did what it should... headlight, horn, signals. So many wires and connectors stuffed behind that horn.

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Dnor72 · « **Reply #13 on:** May 26, 2017, 07:57:52 PM »

Gauges back together, LEDs in the instrument cluster.

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grcamna2 · « **Reply #14 on:** May 26, 2017, 08:37:51 PM »

Great work on that beauty !

Does the CB550SC Nighthawk have 16) hydraulic lifters like it's bigger sibling the CB650SC ?

Dnor72 · « **Reply #15 on:** May 27, 2017, 06:18:30 AM »

Quote from: grcamna2 on May 26, 2017, 08:37:51 PM

Great work on that beauty !
Does the CB550SC Nighthawk have 16) hydraulic lifters like it's bigger sibling the CB650SC ?

Thanks grcamna2. It does have the 16 hydraulic lifters.

It's a bit of a weirdo bike, one year only. It also shares the head and cams with the 1983+ CB650SC. Lots of common parts in the engine.

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grcamna2 · « **Reply #16 on:** May 27, 2017, 07:30:22 AM »

I have had small experience w/ an 83' CB650SC w/ some clogged/collapsing hydraulic lifters.. I gave the customer a price(I quoted replacing all of them..)to fix the bike and he didn't come back.The bike wouldn't run very well the way it was.The owners need to use quality oil and change it regularly on these excellent high performance engines and that's rare w/ most used bike buyers.
Those lifters do get sludge,etc. in them that clogs them and then they don't work too well.I have heard of one person who removed them and somehow manually cleaned/pumped them out and he didn't have any more problems.

Dnor72 · « **Reply #17 on:** May 27, 2017, 07:36:15 AM »

Quote from: grcamna2 on May 27, 2017, 07:30:22 AM

I have had small experience w/ an 83' CB650SC w/ some clogged/collapsing hydraulic lifters.. I gave the customer a price(I quoted replacing all of them..)to fix the bike and he didn't come back.The bike wouldn't run very well the way it was.The owners need to use quality oil and change it regularly on these excellent high performance engines and that's rare w/ most used bike buyers.
Those lifters do get sludge,etc. in them that clogs them and then they don't work too well.I have heard of one person who removed them and somehow manually cleaned/pumped them out and he didn't have any more problems.

The Honda service manual has a procedure using kerosene and a 1/16" drill bit to submerge them and pump the sludge and bubbles out. I haven't gotten there yet.

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grcamna2 · « **Reply #18 on:** May 27, 2017, 07:47:10 AM »

That's nice that the oem service manual has that procedure in it Dnor.

Dnor72 · « **Reply #19 on:** May 27, 2017, 08:16:57 AM »

Quote from: grcamna2 on May 27, 2017, 07:47:10 AM

That's nice that the oem service manual has that procedure in it Dnor.

I haven't found a whole lot of resources online for these bikes. The Nighthawk forums aren't nearly as active as SOHC4 is.

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