I just bought a 1977 Suzuki GS750 the other day and I was able to get it started up if I jump start it. The whole fuel system is looking great but for some reason my bike isn't wanting to rev up or give me much power. I found out that if I keep the jumper cables connected to the bike battery and another battery that the bike will rev its heart out without a problem, but once I take the cables off it'll only idle and it'll kill itself if I give it too much gas. I figured out that if I turn my headlight on I can get about 4k rpm and if I turn my hi beams on I can get about 6k. I check ground resistance to the battery and was only getting 0.4 ohms. I checked battery voltage without the jumper cables on and I'm only getting 3.6VDC. I obviously have a problem with my charging system but I've never seen or heard about a bike that runs better with the more electricity you're using. I read about these early GS models having a single wire in the charging system that's been notorious for shorting out and causing issues, so I was wondering if that's it? If so, where do I find the wire and how do I test it? If not that, then what're some other ideas/tests I can do to see if it's the stator or reg/rec? I don't think this older model has a CDI box either, I'm pretty sure it's points. Any help is appreciated. Thanks!