Hi, i've never really posted here; but here's the story. Maybe someone here can give me an idea of what is happening. Please excuse the long ass story, but i'm trying to include every detail I can to help the diagnosis.
I picked up an '82 Honda CB750SC Nighthawk for my dad's Christmas present last week. Beautiful condition, ran perfect too. The night I brought it home we fired it up and took it for a few short rides around the block. What we had noticed, was that after the bike had warmed up more, the revs would sit at 3000 rpm. We played with it seeing if giving it shots of throttle would bring it back down but it didn't. We checked the throttle cables and choke cables which were good and had proper slack. Still nothing, idled at 3000 rpm and wanted to increase the longer we let it idle.
So we fired it up again the next day and this time let it sit. It idled normally for about five minutes, then we gave it a few shots of throttle, it remained normal. A minute later we revved it up again, and this time it stuck at 3000rpm again. Once again we checked all cables and linkage and they were fine.
So today we decided to tackle it (my friend and I). We pulled the seat and tank off and moved the airbox and carbs away from the engine and watched the throttle plates move as we pulled the throttle. They all moved perfectly and returned to their normal positions, as did the choke. They were all perfectly clean. So we put a small shot of carb cleaner in each carb and reassembled everything. As we turned it over, it fired for a short period of time (which is what we expected because we disconnected the fuel line and it would have to run for a bit for vacuum to suck fuel back in.) Since the battery is on its last leg, we decided to roll start it to get it going, which usually works (we had done it thrice on previous occaisions.) We couldn't get it to start after trying this numerous times. It would sputter and as we would increase speed, naturally the engine followed until it would die out. We've tried with choke, without choke, with throttle, without throttle, the reserve tank, everything! Can't figure it out!!
We figure it may have flooded so we disconnected the coils and pulled the spark plugs out and cranked it over for a bit. Put the spark plugs back in and that's where we are at with the battery now charging.
Does anyone have any idea what the hell is going on here? We didn't tinker with the carbs at all beside moving the boots off of them to see in. Is it just flooded? I feel like i'm making this out to be more of a problem than it really is, but I bought the bike for my dad for Christmas and now it won't run.
Thanks so much in advance!!