Author Topic: Nighthawk 550 Bobber/Chopper, kinda  (Read 52885 times)

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pikeymick

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Re: Nighthawk 550 Bobber/Chopper, kinda
« Reply #125 on: November 10, 2009, 02:48:23 pm »
I've got that fuse box cover, and a horn, but the horn sounds like a 26 year old horn will.

pikeymick

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Re: Nighthawk 550 Bobber/Chopper, kinda
« Reply #126 on: November 14, 2009, 05:45:24 pm »
This just became a top end rebuild. haha

Offline Alan F.

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Re: Nighthawk 550 Bobber/Chopper, kinda
« Reply #127 on: November 14, 2009, 10:37:59 pm »
Oh no, what happened?

pikeymick

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Re: Nighthawk 550 Bobber/Chopper, kinda
« Reply #128 on: November 14, 2009, 11:55:11 pm »
It was ticking like crazy when I took it for a ride today, and smoking from the tailpipes of 3&4. So I decided to pull the valve covers off and see if I can see anything. I found that two of the oil plated (bikebandit.com part # 202040-001) are missing! Then I kept getting bits of the PO's make a gasket down where the valves where so I decided to pull the cams to clean it out. Then I drop a sleeve from one of the cam holders down into the cavity where the timing chain is DOTE! So I decide that while I'm there I might as well do the rings and put a new headgasket it on (and see what kind of condition the cylinders are in)...

Offline Alan F.

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Re: Nighthawk 550 Bobber/Chopper, kinda
« Reply #129 on: November 15, 2009, 07:07:47 am »
I know what you mean about dropping stuff, I've taken to keeping a telescopic magnet on anything I could potentially drop into a hard to reach place, it's saved me quite a few times.
I guess you can't go too far wrong with a rebuild, Be sure to check those connecting rod bolts too right?  Maybe you'll find rid play you can feel and decide to split the cases later on? 
Someone must know the tricks for rebuilding this engine.
Best of luck.
-Alan

pikeymick

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Re: Nighthawk 550 Bobber/Chopper, kinda
« Reply #130 on: November 15, 2009, 10:34:11 am »
Prognosis not good....











Damn. Cylinders 3&4 were really bad. They were notably loose as I was pulling the cylinders off. I sprayed some PB in 4 and it drained right out. There was noticeable slop. And in the pics is cyl. 3. The worst off. Looks like this isn't going to be a cheap easy project after all. damn.

Offline tomsweb1

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Re: Nighthawk 550 Bobber/Chopper, kinda
« Reply #131 on: November 15, 2009, 01:04:10 pm »
Crap... that really sucks.
Present: 1978 CB750A, 1978 CB400A, 1983 Nighthawk 550, 1984 CM250C

Past: 1977 XL100, 1982 KZ1300

Offline Alan F.

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Re: Nighthawk 550 Bobber/Chopper, kinda
« Reply #132 on: November 15, 2009, 04:41:49 pm »
Here's the crank/pistons page from servicehonda, overbore pistons and rings are available I guess.  I wonder how many ponies you can find with a 1.00 overbore set?
I'm off to ebay to see if any are there...brb.  There's this: http://cgi.ebay.com/ebaymotors/NOS-1983-Honda-CB550SC-CB550-50-Piston_W0QQcmdZViewItemQQhashZitem2c46e30fc2QQitemZ190167846850QQptZMotorcyclesQ5fPartsQ5fAccessories
I wonder what the real pricing is on those parts?
-Alan
« Last Edit: November 15, 2009, 04:45:56 pm by Alan F. »

Offline Alan F.

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Re: Nighthawk 550 Bobber/Chopper, kinda
« Reply #133 on: November 15, 2009, 05:04:20 pm »
OK forget ebay, here's the pricing from http://www.servicehonda.com/parts.php
I wonder if there are any aftermarket pistons and rings available?
-Alan

Offline Alan F.

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Re: Nighthawk 550 Bobber/Chopper, kinda
« Reply #134 on: November 15, 2009, 05:19:45 pm »
I can't seem to find much right now for aftermarket pistons, but stock bore for a 550SC is 60mm same as the dohc 650 nighthawks.
http://www.hondanighthawks.net/650.htm

I'll research the piston and ring prices on that model in a little while.
-Alan

Offline Alan F.

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Re: Nighthawk 550 Bobber/Chopper, kinda
« Reply #135 on: November 15, 2009, 05:53:32 pm »
It seems the CB650SC's use the same rings as the CB550SC's all part numbers are the same as far as rings go.
Piston part numbers for the CB650SC have ME5 in the middle instead of the ME4 that the CB550SC pistons have.
There could be a physical difference between the two that might cause compatibility issues, maybe not. Either way the CB550SC pistons are cheaper from servicehonda than the CB650SC units.
-Alan
« Last Edit: November 15, 2009, 05:56:54 pm by Alan F. »

pikeymick

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Re: Nighthawk 550 Bobber/Chopper, kinda
« Reply #136 on: November 16, 2009, 02:00:06 pm »
Alan you are the man! I wish I could take all of you resources and put them in a database that I could search, although I guess that's kind of what this site is!

On a positive note I found another 1983 CB550SC for sale, and made a deal to purchase it! I might be picking it up tonight or late in the week. It's a complete bike! With valves problems according to the PO. We'll see...

Offline Alan F.

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Re: Nighthawk 550 Bobber/Chopper, kinda
« Reply #137 on: November 16, 2009, 06:14:23 pm »
That's probably the route I'd go if something went wrong with my 92 nighthawk, another engine will run me what $250 ??? and I can probably swap it in in less than a day (or 2)
There just isn't much reason to buy the parts for one of these engines.

I forget just where I read it but a CB650SC engine can be successfully swapped into a CB550SC as a bolt-on, there was some mention of the 650 tank not fitting but the 550 tank cleared the 650 engine just fine... if memory serves.  So if you find a good deal on a CB650SC engine go for it, who'll know?

Best of luck.
-Alan


Offline Alan F.

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Re: Nighthawk 550 Bobber/Chopper, kinda
« Reply #139 on: November 17, 2009, 02:20:04 pm »
That's the guy, but I read the story here: http://dotheton.com/index.php?topic=9427.0
-Alan

pikeymick

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Re: Nighthawk 550 Bobber/Chopper, kinda
« Reply #140 on: November 19, 2009, 08:11:17 am »
Interesting. It was my understanding that the only differences between the engines was bore and stroke, perhaps it's just stroke? Hmmm...

On an update. I bought a donor bike, errrr I bought a bike in better condition for less money than the one I have and it has current registration (in CA the reg stays with the vehicle) which means I'm going to move everything over to the new bike. I'm going to rent a compression gauge this weekend, and I also found a machine shop that said they'd do the cylinders for $25.00 per cylinder.... They just bought out the old shop that was there. I was recommended to them by the guy that machined my wheels. He said he hasn't heard any feedback yet from other people that he sent there, which could be good, could be.

But either way I now have a complete bike with side panels, and a tank with only one dent! Going to figure out soon whether the new engine is usable, or just less devastated.


Offline Laminar

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Re: Nighthawk 550 Bobber/Chopper, kinda
« Reply #141 on: November 19, 2009, 08:16:06 am »
Interesting. It was my understanding that the only differences between the engines was bore and stroke, perhaps it's just stroke? Hmmm...

On an update. I bought a donor bike, errrr I bought a bike in better condition for less money than the one I have and it has current registration (in CA the reg stays with the vehicle) which means I'm going to move everything over to the new bike. I'm going to rent a compression gauge this weekend, and I also found a machine shop that said they'd do the cylinders for $25.00 per cylinder.... They just bought out the old shop that was there. I was recommended to them by the guy that machined my wheels. He said he hasn't heard any feedback yet from other people that he sent there, which could be good, could be.

But either way I now have a complete bike with side panels, and a tank with only one dent! Going to figure out soon whether the new engine is usable, or just less devastated.



Why not just buy a compression gauge? I find mine pretty handy and I'm pretty sure it was less than $30 with the right adapters to fit my car and my bikes.

Offline Alan F.

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Re: Nighthawk 550 Bobber/Chopper, kinda
« Reply #142 on: November 19, 2009, 09:21:06 am »
Cool, lots of parts on hand to pick and choose from is a very good thing.

pikeymick

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Re: Nighthawk 550 Bobber/Chopper, kinda
« Reply #143 on: November 19, 2009, 10:43:51 am »
I'mo hesitant to buy a gauge because I'm trying to spend as absolutely little money as possible...

Offline Laminar

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Re: Nighthawk 550 Bobber/Chopper, kinda
« Reply #144 on: November 19, 2009, 10:57:36 am »
I'mo hesitant to buy a gauge because I'm trying to spend as absolutely little money as possible...

Well then getting into old motorcycles seems like a poor choice.  ;D

pikeymick

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Re: Nighthawk 550 Bobber/Chopper, kinda
« Reply #145 on: November 19, 2009, 11:12:21 am »
It just means renting some tools instead of buying them :-\

pikeymick

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Re: Nighthawk 550 Bobber/Chopper, kinda
« Reply #146 on: November 29, 2009, 05:46:17 pm »
Cylinder #1 60psi (+oil 130psi)
Cylinder #2 130psi
Cylinder #3 30psi
Cylinder #4 90psi

...
To the machine shop

Offline Laminar

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Re: Nighthawk 550 Bobber/Chopper, kinda
« Reply #147 on: November 29, 2009, 06:38:43 pm »
Any change on #3 with oil?

pikeymick

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Re: Nighthawk 550 Bobber/Chopper, kinda
« Reply #148 on: November 29, 2009, 07:48:33 pm »
Any change on #3 with oil?

I need to redo that one with oil. What does adding the oil do, close the gap in the cylinder wall? And does it indicate that it's only the rings?

Offline tomsweb1

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Re: Nighthawk 550 Bobber/Chopper, kinda
« Reply #149 on: November 29, 2009, 08:25:05 pm »
it indicates that there isn't a hole in the cylinder or piston.
Present: 1978 CB750A, 1978 CB400A, 1983 Nighthawk 550, 1984 CM250C

Past: 1977 XL100, 1982 KZ1300