jamescahood

I just recently purchased a 1980 Yamaha XS 400 SG. I was just wondering what oil is best for this bike? The manual I have recommends 20w/50. I know there is special motorcycle engine oil anyone better than the other? Synthetic or conventional? I need new tires as these are pretty dry rotten. IRC RC RS310 90/90B-18 BLK FRONT, IRC RS310 120/90B-16 BLK REAR, Are these pretty good tires for just everyday riding? If anyone has any useful information about tuning this bike or anything I should check out I would greatly appreciate it. I'm new to motorcycle maintance so anything helpful would be great. Thank you in advance! [email protected]