Fix'er Upper Clutch Help

Hello I've been working on my 94' VS800 Intruder that I got for a few hundred dollars. It didn't run when I got it and I got it running yesterday! YAY! Now this is where I say 'BUT' as I put on about 100 miles the clutch doesn't feel right anymore. The clutch will switch gears but when I turn the throttle the bike will very slowly accelerate even when fully turned. The clutch was one of the issues I had fixed when repairing the bike but only the slave/master cylinder and the clutch hose (which are now working fine.) So I noticed the oil level was a bit low so I put some more oil in and it hasn't resolved the issue either and it got me thinking. Could the wrong oil/oil filter cause this issue? It's a car oil and a car oil filter. Any ideas friends?