THIS IS THE NEW KNOB THAT HONDA SELLS FOR THE Z50K0 THRU K2. IT HOLDS THE HANDLEBARS TIGHT IN THE TOP CLAMP MOUNT. 27A @ *NUT_HOLDER HANDLEBAR_KNOB SOLD_EACH Z50 AND CT70 K0_TO_1978 53143-045-000 7/21M (36F) THIS PART IS NEEDED TO LET THE HANDLEBAR KNOB SCREW INTO TO HOLD THE HANDLEBAR TIGHT. OR SOMETHING LIKE THAT.FITS K0 THRU 78 BIKES. 36F