New to me Nighthawk project

[84cb700scdlb]

I just bought an '84 Nighthawk project.I found one that a guy had started to work on, I know it's not the smartest thing to do, buy something someone has taken partially apart, just because of the unknown. He said the engine had a tapping, kind of a rattling in the upper end so he took it out to inspect it. He said he found a small amount of metal on the oil pump screen and the chain guide had some wear on it and that is where he believed it came from. I looked it over for probably an hour, pulled the oil pan back off, turned the motor over with a wrench on the cam, shined a light up and down in the crankcase and couldn't really find anything that looked worn besides the guide, he has the head off. I know, maybe a rod bearing or a main bearing is down but it turns over easily and I couldn't see any bearing material sticking out, which you can't always but sometimes you can if it has hammered enough. The body is in good shape, no dents or rust in tank, all the plastic is in good shape, it had an extra instrument cluster with it, the one he said is original shows 15,xxx miles but has a crack in the lens and the one on it now shows 24,xxx. It has been painted a metallic charcoal gray and doesn't have any of the nighthawk decals on it, which I plan to fix if/when I get it running. I am very mechanically inclined and won't have any problem putting it back together, I have worked on cars all my life, along with the occasional dirt bike and 4-wheeler. What I was needing is some advice, should I just buy new guides and tensioner spring along with the appropriate gaskets and put it back together to see what happens or tear it down further for inspection? Also it came with a Honda shop manual.   

[highwayjamin]

You already have it apart.I would keep going on the tear down,then all new parts.The you should have a bike that will last you a really long time.But I'am like you,service technician all my life. Good luck and keep us posted.

[njpaddler]

Common with these bikes, to the point of "expect it to happen if it hasn't yet", the rattling was the cam chain due to failure of the tensioner spring. You'll find that said spring is unobtainable, so your quest is to seek out a replacement of equal size and tension from some other source.

Other than that, you have a fairly bullet-proof engine and the Nighthawk is known to be very reliable for many years service, given proper care and feeding.

Good decision buying it, even if uncertain at first- you won't regret it.

[gammer]

Common issues with the Nighthawk S:
- Alternator chain breaks anywhere between 40,000 - 60,000 Km's (25,000 - 40,000 Miles). Symptoms will be starter spins but doesn't engage. This is not from a faulty chain, but from the alternator chain tensioner release rod breaking off and snapping the chain. Both the tensioner and chain are discontinued. But you can source the chain from aftermarket places that make custom chains. The tensioner doesn't need the release rod to operate. In fact if you install the old tensioner without the release rod, you'll be garunteed that it wont break again.
- The shifting forks can bend easily if bike is abused (while shifting). Can cause 2nd gear to be temperamental or not function at all.
- Can blow blue smoke when first starting up
- Leak oil from where the starter meets the engine. Leak oil from where the alternator meets the engine. Leak oil from the crank seal on the left side, behind the 'pick-ups'.

Other then that, its a solid bike if regular maintenance is performed.