V8pel Posted January 31, 2023 Share Posted January 31, 2023 Have many other owners suffered the collet issue on the exhaust valves ? my sons 2021 MT 07 suffered the same symptoms, on acceleration throttle wide open , a large backfire, flame out of the exhaust from unburnt fuel , then a missfire on one cylinder i know there was another member with the same issue this engine had only covered 6000 miles , its been serviced twice from new by us , and although under warranty, it has a de,cat exhaust and re map , quick shifter so decided to investigate it ourselves just really wanted to know if any others had suffered a similar fate ? Link to comment Share on other sites More sharing options...
M. Hausknecht Posted January 31, 2023 Share Posted January 31, 2023 (edited) Oh never mind. I just saw your other post. So, you've determined the collet came off? Wow, that is surprising for a motor assembled by Yamaha. It is not a widespread problem. There is certainly something wrong, but what makes you think there is an issue with the exhaust valve collets? Who did the remapping of the ECU and with what base map? Have you pulled the plugs and, if so, what do they look like? Mechanically, except for an occassionally flakey cam chain tensioner, the CP2 motor is nearly bullet-proof. There are some base maps being provided by some tuners (FTECU is one example), however, with entirely too much ignition advance, especially for the #1 cylinder. Edited January 31, 2023 by M. Hausknecht Link to comment Share on other sites More sharing options...
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