Topic: Nighthawk 550 Bobber/Chopper, kinda

[Alan F.]

Definitely seperate the carbs, any junk from the tank that ever got into the carbs entered thru there.
-Alan

[pikeymick]

Well #$%*. If I'm not the tits on a celibate monkey. I separated the carbs, not too much was in there but I cleaned em out. Sprayed carb cleaner in until I saw it coming out the other ends. Took the adjuster screws off the bottom (counting the turns from locked in), sprayed those grubby bastards clean.

This morning before work I decided to test the coils so I switched all the wires around so that 2&4 were coming from the left coil and 1&3 were coming from the right coil. Still runs. With only 1&2 getting hot. (this was pre-separating the carbs)

So I fired her up again post carb separation with the coils flipped. Still only getting 1&2. I wonder what it would like like to launch this off of the end of the new Bay Bridge they're building here in SF?

[Laminar]

Did you physically push anything (like a guitar string) through the jets?

If you open up the bowl drains, does an equal amount of gas come out of each carb?

[pikeymick]

Yeah I replaced two of the slow jets as well. Light is visible through all of them as well as having passed a wire through them. I'd eat dinner out of my carbs if it wouldn't definitely clog them, they're that clean.

I'm frustrated. In the morning I'm going to switch the coils back. Then if that doesn't work try and borrow a compression gauge and see what I'm working with, I just don't know.

[pikeymick]

Well before I end up having to rebuild the whole motor 

I've got new plans for the bike. As you guys suggested early on it has the lines of a cruiser allready so I may as well utilize that heritage. I'm going to do a bobber/chopper thingamajig... length wise I feel like the CB's look a little funny as chopper's cause they are too short, but a hybrid might be good, think Triumphish.

I came up with a logo for the tank last night Satin Black with the logo in white on the tank (facing up)

[Alan F.]

A bobber ? OK.  I wonder if the diaphragms are OK and the slides slide freely in their bores?  There are also a few vacuum passages that go from the carb inlet or throat to the top of the diaphragms, make sure they're clean and clear too. and make sure the carb top gaskets are good too while you're in there.

Without a compression tester you can do a little test with your finger held over an open spark plug hole while cranking the engine over, be sure the kill switch won't let any sparks happen though...

Don't push it off a bridge yet, you're winning with every bit of crud you get out of there, eventually you'll clean or adjust the right thing and all will be solved. As an added benefit, all of the cleaned and adjusted bits you've done on the way to that solution will prevent other potential issues from going critical anytime soon.
In the end this process you're going through will improve the bike's reliability, strengthen your skills and confidence and you'll feels tons better after you've finished the project for going the distance with it.
-Alan

[Laminar]

Yeah, the bike's lines are perfect for a bobber.

[pikeymick]

Good talk Alan, thanks for the motivation. And with that fresh perspective I decided to go at er this morning rather than leave it, which was my first desire.

It's ALIVE!! After the full break down of the carbs last night I hadn't put the coils and wires back to their proper locations. When I went to rewire it this morning I noticed I had a ground and lead backwards, which from my understanding means it'll spark, but a weak one. Put everything back the way it belongs, and sure enough all 4 are firing!! Woo Hooo! WOO friggin HOOOOO!

And then I just noticed I have a bar from my mtb and grips that'll fit up nice and look much better than those ape hangers. And are definitely strong enough!

[Laminar]

Fantastic!

Out of curiosity, which way is the "correct" way? Colored wire on top, or black/white wire on top? And let's see some pictures of the bike!

[pikeymick]

B&W on bottom and color on top

[Alan F.]

Good talk Alan, thanks for the motivation......and sure enough all 4 are firing!! Woo Hooo! WOO friggin HOOOOO!
And then I just noticed I have a bar from my mtb and grips that'll fit up nice and look much better than those ape hangers. And are definitely strong enough!

No problemo, woo!  yes,    woo!  (j/k) AWESOME!!!!!!!!!!!!!!!

I was wondering if bars from a mtn bike would bolt up, thanks for the tip there, I just hope they're wide enough to be legal....my state (Mass.) has a spec for how wide bars have to be...and no more sideways license plates here either....grr.

AWESOME!!!!!!!!!!!!!!!

AWESOME!!!!!!!!!!!!!!!

AWESOME!!!!!!!!!!!!!!!

[Laminar]

I have a fairly narrow set of bars from a Suzuki SV650 that I had on the bike for a while. They just seemed a little too narrow for comfort and I really did a number on my tank with the throttle cables and choke cable. Also, the banjo bolts on the clutch and brake master cylinders interfere with the fork mounting points, and if the master cylinders are mounted on a more standard set of bars, they're no longer level, which makes them hard to fill. Oh, and the mirrors will angle themselves in, making it impossible to see behind you.

[Alan F.]

Yeah I guess Honda wanted everything to work well with the stock bars.  I wonder if the controls and master cylinder(s) from a dohc 650 nighthawk would fit without mods?
-Alan

[Laminar]

The clutch would be fine but the brake master cylinder is designed for a dual front brake system, so it might be way too stiff.

[Alan F.]

Alright, so another master cylinder form a Honda that uses the same style caliper should do the trick and be easy enough to find.
For example my 81 CM400C has the same brake setup as the 550NH allot of bikes did, a quick trip to Denniskirk's website yielded this list of bikes that use the same master cylinder rebuild kit, one of these master cylinders is certain to fit the bill, be available, and be cheap.  Cheers!
 
http://www.denniskirk.com/jsp/product_catalog/Product.jsp?skuId=191742&store=Main&catId=&productId=p191749&leafCatId=&mmyId=15618#fitment
•Part 191742 fits the following machines:
•1981 Honda CB400T Hawk
•1982 Honda CB450SC Nighthawk
•1983 Honda CB450SC Nighthawk
•1985 Honda CB450SC Nighthawk
•1986 Honda CB450SC Nighthawk
•1982 Honda CB450T Hawk
•1983 Honda CB550SC Nighthawk
•1981 Honda CB650
•1982 Honda CB650
•1981 Honda CB750K
•1982 Honda CB750K
•1989 Honda CBR600F
•1990 Honda CBR600F
•1987 Honda CBR600F Hurricane
•1988 Honda CBR600F Hurricane
•1981 Honda CM400A Hondamatic
•1981 Honda CM400C Custom
•1981 Honda CM400T
•1982 Honda CM450A Hondamatic
•1983 Honda CM450A Hondamatic
•1982 Honda CM450C Custom
•1986 Honda CN250 Helix
•1987 Honda CN250 Helix
•1992 Honda CN250 Helix
•1993 Honda CN250 Helix
•1994 Honda CN250 Helix
•1981 Honda CX500C Custom
•1982 Honda CX500C Custom
•1981 Honda CX500D Deluxe
•1983 Honda CX650T Turbo
•1982 Honda FT500 Ascot
•1983 Honda FT500 Ascot
•1983 Honda GL1100A Gold Wing Aspencade
•1983 Honda GL1100 Gold Wing
•1983 Honda GL1100I Gold Wing Interstate
•1984 Honda GL1200 Gold Wing
•1999 Honda GL1500CF Valkyrie Interstate
•2000 Honda GL1500CF Valkyrie Interstate
•2001 Honda GL1500CF Valkyrie Interstate
•1997 Honda GL1500CT Valkyrie Tourer
•1998 Honda GL1500CT Valkyrie Tourer
•1999 Honda GL1500CT Valkyrie Tourer
•2000 Honda GL1500CT Valkyrie Tourer
•1997 Honda GL1500C Valkyrie
•1998 Honda GL1500C Valkyrie
•1999 Honda GL1500C Valkyrie
•2000 Honda GL1500C Valkyrie
•1981 Honda GL500 Silver Wing
•1982 Honda GL500 Silver Wing
•1989 Honda PC800 Pacific Coast
•1990 Honda PC800 Pacific Coast
•1994 Honda PC800 Pacific Coast
•1995 Honda PC800 Pacific Coast
•1996 Honda PC800 Pacific Coast
•1997 Honda PC800 Pacific Coast
•1998 Honda PC800 Pacific Coast
•1983 Honda VT500C Shadow
•1984 Honda VT500C Shadow
•1985 Honda VT500C Shadow
•1986 Honda VT500C Shadow
•1983 Honda VT500FT Ascot
•1984 Honda VT500FT Ascot
•1986 Honda VT700C Shadow
•1987 Honda VT700C Shadow

[Laminar]

Some of those bikes have pullback bars like the NH550, and I'm not aware of any Goldwing models that came with a single front brake. But yes, just about any single-disc master cylinder should be okay.

[Alan F.]

well, that's the list of bikes that the same master cylinder kit fits, I'll agree with your statements.  One is certain to fit the bill as I said before. 

[pikeymick]

Alright my fellow nighthawk friends! Here is an update:

I spent the past couple of days, now that's she alive, cleaning up and getting the other systems solid and safe. I still can't get the intake boots to fit between the carbs and the airbox, it's about 2mm short even with the airbox slid all the way forward, additionally the boots barely fit onto the intake side of the carbs. I was not going to give up easily so I decided to soak the boots in boiling water. It softened them up the better than new! I slipped them on the carbs and let them cool. The first time they just popped back off the carbs as they cooled down and contracted. So I remounted the airbox, after pulling it off and cleaning it out and re-sealing it with shoe goop, and used the airbox to hold the boots forward onto the carbs.

I threw some gaffers tape in the space for now.

I pulled the layers of vinyl, black duct tape, and grey duct tape, old original vinyl remnants to get down to the seat pan (they were nailed and screwed to the seat pan). I noticed that the seat pan has a set of forward latches but the frame has no reciprocating things to hold them, hmmmm the space where it looks like they should be is just forward of the air box attachment screws. The seat pan is also a perfect shape for the style I'm going for. I'm going to cut out the second seat with a small lip on the back. If I keep the rear seat I'll mock it up as a second seat, like a small cushion for going 2 up.


I pulled off all the idiot lights and the dashboard assembly
(what do you get when you flip over ape hangers?)

(huge clubman bars)

The MTB bars didn't fit, way too short, and the bend isn't accommodating for triple clamps (shoulda figured as much). Tomorrow I'm going to buy some more steel wool, and try to find a replacement Clutch w/MC (did some research and anyone should fit as long as the bar diameter is the same)

I'm going to get some foam for the seat and start making the seat cover and ask my roommate if I can use her sewing machine!

[Laminar]

I picked up some generic hose clamps to attach the intake boots onto the carbs.

[tomsweb1]

Wow, the pipes are in great shape! you lucked out there.

[Laminar]

Out of curiosity, do the pipes have a kind of ripple an inch or two before the outlets? Mine do, and the other 550 I've seen is the same way.

[Alan F.]

So it's firing on all four now, any updates?

[tomsweb1]

can you get a better pic of the 'ripple'? Then I can tell you if either of mine had that also.

[Alan F.]

I checked out a few 550NH pipes on ebay, here's a pic that seems to be what we're talking about here, am I right?
-Alan

[Laminar]

I checked out a few 550NH pipes on ebay, here's a pic that seems to be what we're talking about here, am I right?
-Alan

Yes, exactly. Mine have cracked and started rusting at that point.