I am on a pre 1985 nikishi custom sport, i'm upgrading, willing to spend some money, not too much.

The chain is slipping, i am not to bike savy. 12 speed. I have it on the smaller crank on the peddle crank but on the crank on the rear tire i move it all the way to the top crank. I assume lower gear ratio
(i am somewhat car savy lol) On the rear crank it will slip from the top crank to the middle crank, which is the 3rd crank from the top or bottom, however you wish to look at it

What is the problem and solution. ( not too expensive but i am willing to pay a fair amount)

How old is the chain?

it came with the bike, so i wouldnt know. Besides i am a noob to biking, i just dont like it when i am going up the hill, chain slips and i almost eat it, happend to me twice today on the same hill. Another thing, i hear a metal contact sound as i pedal, i dont know if that helps.

However, that might be the bedals because when i am not pedling and going down hill the odd metal contact sound is heard,

tighten the shift lever.

Exactly

Ok, i have to problem doing the work myself, when you say shift levers i assume the levers on the stem. HOw would i tighten them.. I am looking at the bike right now and i see a large screw on the side. Will there be But i asume that is the screw that holds the lever in place, that screw is as tight as its gona get. I was messing with some screws on what I assume people refer to the derailer, now its slipping more, lol...thats just the way i am, i mess with things untill i break them, then learn to fix them

If tightening the shift lever (increase the friction that it takes to move the lever by tightening the screw or loop that holds it on)does not work, it probably is a matter of lubricating or replacing the cables. Sometimes a shot of WD-40 in the end of the cable housings will do it but more often you must loosen the cable and pull out a short section to expose the part that is hidden within the housing. Then a tad of grease or a good wipe down with a solvent will free thinks up when retracted into the cable housing. If you have too much friction in the cable, it will not shift when the lever is moved (in this case loosened) and it will shift at some later time of its own choosing. Your rear derailleur is spring loaded to move toward the smallest sprocket and thats what yours is doing on its own. One of these two solutions should solve the problem. Good luck. Its a solvable problem. tom