Topic: New Member - Looking for general technical advice with 1982 CB650SC Nighthawk

[tykenfitz]

Hey Everyone, nice to meet you! I couldn't find a "New Member" or "Introductions" section, so please move this if it's in the wrong place.

So I bought this bike at the start of June:


I've heard that this model-year bike actually much more similar to same-era CB650s and CB650Cs than they are to '83+ model year nighthawks.  Is there any sort of definitive list of which parts are interchangeable between model and years?

And love it so far, bought the Clymer manual, so it's definitely a keeper! I've rebuilt the petcock with a new o-ring so it no longer leaks, relocated + fixed the taillights and added a latch to the seat "frame" so it no longer slides around when I accelerate haha.  There are a few things that are still funky with it though, including:

• Small oil leak from cylinder/head
• Neutral light always on
• needs new brake pads + adjustment + fluid bled

The small oil leak is my biggest concern, I originally thought it was coming from the valve covers, but now I'm not so sure. I have read that these SOHC 4 tend to have issues with leaking oil from the top-end. Do you guys know where I would be able to get gaskets in order to do a top-end rebuild if it comes down to that?

As for the neutral light, I've heard that it can either be a bad switch or a short-to-ground in the wiring. I've not messed with this before, so how to I troubleshoot to drill down to where the problem might be?

On a lighter note, a lot of the plastic/pretty parts are missing or looking like crap, so if ya know anyone on this site who has done up a nice custom job on an '82 Nighthawk, please let me know. I'd love to look at some pics for inspiration!

Thanks in advance for any help!

All the best,
Fitz

[tykenfitz]

Oh, I also forgot to mention that I have had a hell of a time trying to start the thing. I'd have to crank it 'til the battery was almost dead with full choke to get it going.  Now I give it 3 cranks of the throttle before cranking and it seems to start much, much easier.

Is that standard practice on an older bike like that or does it indicate something's wrong with my carbs? Perhaps it's running to lean at idle RPM?

I haven't done any carb or engine work since getting it, been focusing on easier stuff first, any idea how tough it is to get the carbs off one of these bikes? On my Ninja it is a waking nightmare haha.

[bryanj]

Not good starting can be the start of dying ignition modules

[tykenfitz]

Not good starting can be the start of dying ignition modules

Thanks for the heads up! I'm not super familiar with the ignitions systems used on these bikes, how do I go about troubleshooting if that is indeed the problem?

[bryanj]

You need the proper Honda workshop manual and a decent multimeter, forget the cheaper Haynes, Clymer etv