I have a 2001 Suzuki SV650S and I had to drain the radiator. I am wondering what type of antifreeze and what the ratio of antifreeze and water should be? Can I use car antifreeze or does it have to be special for motorcycles?
Check with a Suzuki dealer first. I'm fairly sure you can use car anti freeze but there are many different kinds out there (like Dex-cool and the yellow stuff Ford uses) and your bike may call for a certain kind. Both my Ninja and Raptor 4 wheeler take the green stuff and I ran the green stuff in my RM125 with no problems. I'm guessing as long as it is safe for aluminum it's ok but again I'm guessing.
Both my past Suzuki GT750 LeMans and Honda Gold-Wings simply used a 50/50 mixture of Ethylene Glycol (undiluted Automotive Anti-Freeze) and water. On the latter Distilled Water was specified to hinder corrosion of the aluminum blocks (as tap water would surely accelerate). Funny, I'm thinking that might be a good idea for ALL water-cooled systems, cars and bikes?! In any case, be sure to be extra careful changing and disposing of that used Anti-Freeze. The darn stuff is absolutely deadly to wildlife who are attracted to the sweet scent. There is a (?) non-toxic environmentally safe one out on the market now I think? That would be my choice IF after contacting the manufacturer you get a thumbs up. ;-) All I would add is when you go to change this stuff, make sure you drain the block as well as the radiator. Never known a system yet where you could just easily get it ALL out thru the radiator drain plug.
You should always use plain green anti-freeze. The cheap stuff. DexCool (orange) has known aluminum corrosion issues. G-05 (yellow) is a mix of silicate and organic based coolant. It has superior aluminum protection, but it coats components to help them resist corrosion and repair damage. It's a great idea, but it can also cause buildup.
The best thing for most any motorcycle is plain green antifreeze and distilled water at a 50/50 ratio.