Is your goal with the bike to keep it or sell it? If you're selling it, I see why you just want to check compression. If you're keeping it, you need to set up the electrical correctly and stop trying to bypass or eliminate things. I understand you don't have a lot of knowledge in all of this, that's ok. But you can't pick and choose what you want to bypass and selectively wire up when you don't have the knowledge to do it. You may very well get there someday, but that day isn't today. You could very well make things worse by melting another circuit, destroying a battery, etc. So, what is it you want to do with this bike?