So I just picked up a 1988 Yamaha Phazer. Starts, Runs, Idles great. Even drives well. But I feel there is something wrong. It won't climb over 5000-5500 RPM and seems like it should be faster. I played around with the mixture screws and adjusted the idle. But it didn't seem to make a difference. I reset the carbs to stock mix and then played around with it. Then just set it back to where it was when i bought it. The guy i bought it from said he replaced the pilot jets. Not sure if I should replace the main jets. Any thoughts guys and gals?