Topic: 83 Nighthawk 550 question

[bull city]

I'm thinking of getting an 83 Nighthawk 550, but only if I can do something about the forks. How hard is it to mod them to a more standard look? Can I drop the triple tree and put on clip-ons? Are the forks easily switched out with other forks?

I am looking to to a cafe style mod.

Thanks-

[Duke McDukiedook]

I think you want to post your question in this section.

http://forums.sohc4.net/index.php?board=10.0

[Laminar]

Check this thread out for good info.

[Alan F.]

And if you decide on performing a swap, check out some of the free info I've got parked at http://sites.google.com/site/alansdocuments/
-A

[bull city]

Check this thread out for good info.

I searched but didn't find that one. Thanks-

[Alan F.]

Check this thread out for good info.

I searched but didn't find that one. Thanks-

Huh?  just click the link... or do I misunderstand?

[bull city]

I was just saying I had already search the forums for my answer but must have missed that thread.

I'm caught between buying two bikes right now. One is a 74 550 and the 83 550NH. The nighthawk has been garage kept and is great condition for 700 "very negotiable". The 74 is taken completely apart right now, but by a friend who has all the parts. That is for $1000, but he also has a box of parts totaling $1300 from the restoration he was going to do. Everything from new tires, exhaust, clutch, complete new ignition, fork springs, just a whole bunch of what I would be buying if I bought a $300 CB550.

[Alan F.]

Wow, that 74 sounds like fun.  There are a few here with 550SC's but there's virtually unlimitted know-how here to answer questions on the 74 550.
Besides 74 was the first year of the 550, that makes it a K0 model, very cool.
-Alan

[bull city]

It does sound fun, but I'm not sure I'm ready for that. I have a gut feeling I'd be in over my head. It is totally... totally... in pieces.

[Laminar]

You can find any help you'll need here, and you'll learn a ton putting it back together.

That being said, the Nighthawk will absolutely blow away the '74. No contest.

[bull city]

That's what I hear. Two things I don't like about the NightHawk- rake and gas tank. I can live with the low range, but have to do something about rake. If it is as easy is dropping the triple tree, then that shouldn't be an issue. And really, from pics Ive seen online, it looks much better after you get the ape hangers off IMHO.

[Laminar]

That's what I hear. Two things I don't like about the NightHawk- rake and gas tank. I can live with the low range, but have to do something about rake. If it is as easy is dropping the triple tree, then that shouldn't be an issue. And really, from pics Ive seen online, it looks much better after you get the ape hangers off IMHO.

With some normal handlebars, it looks and handles about 1000x better. and wheelies are much easier

[bull city]

Ive seen that pic before. It looks good.

Do you have a side view?

[Laminar]

[Alan F.]

It's really only a 29 degree neck angle, with shorter forks it should look much better. 

[bull city]

thanks-

That's a nice looking bike. I'm coming from an 08 Ninja 250. I'm ready to get something a little more vintage and a wee bit faster.

[Laminar]

It's really only a 29 degree neck angle, with shorter forks it should look much better. 

And I feel like the headlight is mounted kind of high, which exaggerates how tall the forks are.

[bull city]

so good lord... I was looking and comparing on the net about the speed of this bike and it's looking like it just below being as fast as 600 supersports.

So does this sound about right? From a '83 cruiser?


And I never noticed how high the headlamp is. You're right about it making the forks look longer.

[Laminar]

so good lord... I was looking and comparing on the net about the speed of this bike and it's looking like it just below being as fast as 600 supersports.

So does this sound about right? From a '83 cruiser?

It won't be anywhere near as fast as a modern 600cc sport bike. I believe it ran a quarter mile in the mid-12s, which puts it about on par with the SOHC CB750s and faster than most Harleys, but you won't touch a sport bike with 100 fewer pounds and twice the horsepower.

I've embarassed Corvettes, RX-8s, and more, but I've been blown away by a CBR-900 and some flavor of GSX-R.

[bull city]

I made the deal last night-

600 bucks for an 83 550 NH garage kept. 5000 miles.

It hasn't been started in 5 years but ran perfectly before that. I trust the folks because they work with my wife, are in their 60's, and are loaded so there is no reason to pull a fast one on me.

So problems first-

Front brake is locked. Doing some research on this site (and help me if I am wrong) I should bleed a bit first to see if it releases them? If that doesn't work- there is some sort of very small hole that is an exhaust that relieves pressure from the piston so that the piston can release. I should get a guitar string and try to clean that out. Does this sound right and is this easy to find? Lastly- the piston has rusted to the caliper and immediate rebuild is needed. If that is the case, how do I release the brake to get the bike home?

It needs front turn signals.

Of course it needs a battery.

Other than that there are no major problems except for starting an engine that has sat for 5 years. What precautions should I take before I try to crank it? Should I switch out the gas and clean the carbs before I start it, or can that wait until I get it home (about 3 miles)? And yes my first choice is to ride it home rather than push 430 lbs. of dead weight up into my pick-up.

And on the speed- I found the stats being 4.8 0-60 and 12.64 on the 1/4, which puts it up there with the Bandit and like bikes, which I was considering the class beneath SS. Which I find is surprising speed from this bike.

Thanks for all your replies so far.

[Laminar]

Fresh gas and a thorough carb cleaning are a must. Don't try and do "just enough," you'll end up pulling the carbs off three or four different times because you didn't quite get everything the previous times.

An oil and filter change would be a good idea - five year old oil isn't to be trusted.

Check the air filter and make sure there are no rodent nests or insects in there.

You might be able to pull the caliper off of the fork and compress the pistons with a C-clamp, but you might want to pull the pads off first, which isn't easy on a bike that's been sitting a long time.

[Alan F.]

And a rule of thumb with any bike purchase, pump up those tires before you try to push it anywhere...even onto a trailer.  It'll be so much easier without the excess drag.

if you do decide to ride it home, be sure that front brake is functional.
you want to be able to trust it.  new fluid will be needed, just fill the reservior and gently pump the lever a few times, open the bleeder at the caliper and drain out all f that ugly old brake fluid until new brake fluid comes out the bleeder (it'll just look cleaner) be sure to keep filling the reservior so it doesn't run dry.

One tip is to attach a length of small clear hose to the bleeder, the other end into a jar to catch the old brake fluid.

You will probably need to rebuild the master cylinder and caliper later on anyway though. 

And be careful loosening the brake bleeder, you'll want to use only a box-end wrench so it doesn't strip.
Good luck and keep posting your progress.
-Alan

And search the web for the Honda CBX550, it's the same engine in a sportier bike that Honda never brought to the states.

[bull city]

I'm picking up the bike tomorrow and hope to get on the carbs this weekend.

I'm pretty intimidated by the whole carb thing. On one hand it looks completely complicated. Taking them off and on, apart and back together, and cleaning them doesn't seem hard in the least bit. It's the tuning of the carbs after I am done that scares the heck out of me. On the other hand it seems like a lot of people do this on their own so it can't be too terribly hard.

How hard is it to do?

What carb specific tools do I need? Do I need calipers and such?

Is it as simple as remembering how many turns it took to take the jets out and just repeating the process?

I haven't found a good tutorial about how to get the carbs back in working order.

[Laminar]

The Nighthawk's carbs are fairly simple. The idle circuit isn't adjustable. The float level isn't adjustable. Getting them on and off of the bike IS the hard part, if you keep the stock air filter (best choice) and exhaust, you don't have to do any tuning and it will run great.

[bull city]

so there is no tuning of the jets? just take em out, clean them,  and put them back in?

That's probably why no tutorials have mentioned it.

[Laminar]

so there is no tuning of the jets? just take em out, clean them,  and put them back in?

That's probably why no tutorials have mentioned it.

Correct. They get screwed in fully. Carbs on the SOHCs have adjustable metal floats and a screw on each carb to adjust idle mixture, but the Nighthawk has plastic non-adjustable floats and no idle screws.

One thing you will want to do is at least a bench sync of the carbs. You want to make sure that when you open the throttle, all four throttle plates are opening up the same amount. If one opens more than the others, that cylinder will be doing an unequal amount of work and the bike won't run right.

What I do is take two 1/8" drill bits. I open the throttle and place the non-drill end of the bit into one carb (#2 is a good choice) so that when the throttle plates close, the carb's throttle plate closes on the drill bit and it holds the plates a little bit open. Then I go through and try and slide the non-drill end of the other drill bit under the other three throttle plates. If it slides in too easily, I close that throttle plate a little bit by adjusting the linkage between the throttle plates. If there's a lot of resistance or it doesn't slide it at all, I open that plate a little bit. Keep in mind that if you use #2 as the standard, adjusting #3 affects #4, so do #3 before #4. It only takes a few minutes, it's as easy as turning a screw, and the results are great.

[bull city]

hey Laminar, can you help me on this?

Got the new bike and I am going through to get everything functioning.

The brakes were locked, I took them off, pressed the piston back in, flushed with new fluid and they seem to be doing well. I plan on rebuilding them as soon as I get everything functioning. No point in spending money on something before assessing the whole bike.

The clutch: the master cylinder was pretty much dry. The clutch would not engage and there was no resistance on the lever. So I flushed the system with new brake fluid. The bleed hose was coming out clear and I was getting a lot pushed out with every squeeze. But- I never got any resistance on the lever, the clutch would still not engage. What should I look for next?

I haven't started the bike yet and no battery is hooked up at the moment.


Thanks-

[bull city]

wait.. since this is a wet clutch and I need engine oil for it to work, should I run the engine a bit to see if that solves the prob? I'll try that.

[Laminar]

You should get resistance at the lever without running the engine. As far as I know, the fact that it's a wet clutch doesn't affect its engagement or disengagement.

What method are you using to bleed?

When I flushed my clutch fluid, I grabbed a brake bleeder kit (basically a little jar with a tube going into the bottom of it) at an auto parts store. I put a little fluid in the jar so that the tube was immersed. I then filled up the clutch line by putting a funnel over the banjo fitting and pouring fluid in there.

To bleed, I'd pump the clutch lever a few times, hold the lever in, then open and close the bleeder screw. I heard that you don't want to pull the clutch lever all the way to the handle, but leave a 1/2" gap. I'm not sure if that's important or not, but it's what I heard. I made sure that there was lots of fluid in the reservoir and bled it a lot - pump several times, hold the lever in, open and close bleeder screw.

It should eventually build up pressure. It was a pain when I did it, hopefully it works for you.

[ColinMc]

Is the clutch slave OK? I'd check the seals on that...

Wait...the clutch won't engage? As in when you put it in gear you can still roll it no matter what? Since you have to change the oil anyways, i'd pop the clutch cover off and have a look-see in there. Usually by default if there is a problem with the clutch it stays stuck so the clutch is constantly engaged.

[bull city]

I think I had it backwards. I can put the bike in neutral and it rolls, put it in gear and it doesn't. I just cant have it in gear, pull in the clutch and have it roll in gear. is that engaged or disengaged? i figured the pulling of the lever would  "engage" it, but maybe it's counter-intuitive?

Someone on another board said to pull off the slave and put a clamp on it to keep the piston from moving. Not clamp it tight, just keep it from moving.You can evidently bleed it much faster that way. The idea is that brakes have the disc to stop the piston which makes it much easier to bleed brakes.

sorry for my noob questions and thanks for the help.