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Discussion Starter #1
In case there are any Yamaha Engineers trolling this site looking to learn something from real life experience:
My 254 hour, 2070 mile stock 708 has been experiencing the excessive oil usage particularly on hard, long mileage riding days (6-8 ounces/100 miles), it only uses hardly an ounce or two when a slow 40 mile day of trail riding. Instead of going thru our local dealer to try to get this fixed under the gracious warranty extension, who's service manager was less than helpful or encouraging, I decided to invest my time and dollars into doing an overbore and Carillo forged piston and rings. I am now in the middle of tear-down and sent off my cylinder today for the machining. I specifically wanted to report what I found for the original ring end gaps of the factory assembly. The top piston ring had an end gap of .0125" with OEM service manual spec required of .0197". The second ring end gap was .0190" with an OEM service manual spec of .0276". These are significant variations and certainly worth your attention. Sorry I did not check the oil rings for end gap.
I would be happy to donate the OEM piston and all original rings to Yamaha for R&D if desired. I can also share some pretty good photos of the cylinder which only had some minor visual scoring on one side, that you could not even feel. I did not really check the dimension of the cylinder, but it was really close to original 103mm, sorry, but I was not concerned about it since I sent it to a first class machine shop who will bore/hone it properly for the new oversize piston. Contact me via Private Message if the above offer is of any interest and be assured that I will protect your identity as a Yamaha employee.
 

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2017 Wolverine SE
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I am at ~ 450km on my break-in driving

Since the rebuild I have noticed the following.

Observations:
- Engine tone and vibrations/resonating is totally different
- At speed various resonating can be felt
- Idle seems somewhat irregular (not to say it was dead perfect before but certainly more so) But no stalling currently.
 

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Discussion Starter #3
Well it has been a week and no response so I thought I would just bump this to the top in case it was missed.
 
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