Yamasaki YM50-8B, Руководство пользователя

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16
Check-up & Adjustment of Air Valve Gap
Noise will stem from too big gap of the air valve. However if there is too small gap or even no gap at all,
closing of the valve will be hindered, which will cause burn of the valve and output drop. Therefore, the air valve
gap must be checked periodically.
The gap of the air valve should be inspected and adjusted with a cold engine by the following procedures:
1.Remove the caps of the central hole and the top hole (the ignition timing observation hole)in the left
crankcase cover.
2.Remove the caps of the two air valves on the cylinder head.
3.Insert the “T” key into the central hole of the crankcase cover, jam it against the nut of the flying wheel and
then turm the flying wheel clockwise nutil the engraved “T” mark on the flying wheel alin\gns with the engraved
line on the top of the crankcase cover.Swing the rocking arm slightly.A loose rocking arm(which indicates the
existence of clearance) shows that the piston is in the upper stop position of the compressing t\stroke, where the
valve can be adjusted. A tight rocking arm means thar the piston is in the lower stop position of the compressing
stroke, In this case, continuously turn the “T” key clock wise for 360 degrees until the alignment of those engravd
marks, where the valve can be adjustd,Afterwards, check the valve gap by inserting a feeler in between the valve
adjusting screw and the end of the valve.
The specified air valve gap :0.05mm for the intake and exhaust valves respecively.
Brake Checking
(1) pull up the front and rear brakes respectively and check for wear of the brake shoes. If the mark “
△
” on
the brake drum cover aligns with that “
△
” on the brake cam, it means that the brake shoes are already worn to the
limit and have to be replaced.
(2) Replacement should be carried out at a designated service center and it is recommended that the parts made
by our company are used therein.