HONDA MAGNA VF700C RATTLE/CRACKING NOISE

I just had a quick question about my 1985 Honda Magna VF700C. I bought this bike in a perfectly good running condition about a month ago but, it started to make a very slight rattle/whining sound and would get worse when throttle was used. So basically, the higher the RPM, the louder it got. I've asked the person i bought from and she said that she worked on the bike and that it had no existing problems. One thing I did notice is that the clutch would slip sometimes so i'm guessing that it would be a bad clutch. But the problem is, i don't know what a bad clutch sounds like and if it affected the idling of the bike. So as of now, the bike has a dead battery and whenever i turn it on, the idling was great but now, not idling as well. I doubt that it would be the idling adjuster. If anyone knows what may cause this problem, please let me know. I'm very desperate to get this bike which has been sitting for two weeks running. Oh, and also, before the sound came to a cracking point, the noise would ease out after warming up the bike.

Can you give us a guess as to where the sound is coming from?

That model had a recall.
The cylinder heads were made of soft metal and the cam journals would ware out.
That could cause the sound.
If the update wasn't performed, the valve stem keepers can pop out and cause serious damage to the engine.
I'd suggest figuring out the problem before running the engine.

Walk into an authorized Honda dealer and ask how to check if the update was performed.
Usually a set of punch marks after the engine number.