Here's a tip for you folks if you need to replace the o2 controller fitted in the exhaust downpipe and don't wish to pay Yamaha �175 !!!
Buy this one on Ebay for �15 it is slightly longer and you will need to splice the wires together to keep the Yamaha connector, (the four wires are also the correct colours) but it fits a treat and has reduced my surging issues greatly. Since these sensors are almost impossible to test without specialist equipment you may not even know that it is faulty, mine was on a 2013 model!
Ebay Item No is 271898405232