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@ *AIR FILTER ELEMENT CT90K2 K3 K4 K5 K6 1976 1977 1970_TO_1977 (78's_READ) 17211-102-000 1/22A (39A)

FOAM ONLY K2 THRU 1977 CT90's

or ABOUT 1970 TO 1977 CT90'S

1978 models with the crankcase vent tube on the lower front of the airbox take the CT110 foam filter, otherwise the 1978's take this filter.

39A