Cam chain tensioner was somehow adjusted all wrong on TWO CT90's of mine. One was jammed up too tight, making an awful squealing noise when the motor was hot, the other was very slow moving due to spring tension set wrong. I disassembled and figured out how these are supposed to work. Why Honda chose to change up their simple spring mechanism to this Rube Goldberg set-up is beyond me, but they did. Now my engines are very quiet and lots more power when warm.

I imagine that others on here who have had power fade issues when the engine is warm to hot is attributed to the cam chain tensioner making the chain too tight and causing undue bind on the cam drive train.

1970 Yellow CT90 K2   SOLD!!
1974 Orange CT90 K5                 2003 Red/White/Blue BMW Dakar F650GS
1974 Orange CT90 K5 (twins!)    1987 Gold Kawasaki Voyager 1200
1973 Red CT90 K4  SOLD!!         2001 Green Kawasaki KX250