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bf50 valve adjustment

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  • bf50 valve adjustment

    Going to adjust valves on 2001 honda 50 this weekend. I have the seloc manual. It shows to align marks on flywheel and ignition coil. Will this bring it to top dead center of compression stroke? At this position will I be able to adjust exhaust and intake for all three cylinders? I already know the clearances differ from honda to seloc, so i'll go with honda specs. I have a new valve gasket but is the old one reusable? And lastly is there a torque spec for valve cover bolts?, cant find one . Thanks for any help, a t

  • #2
    Re: bf50 valve adjustment

    The valve cover gasket can be used over several times. I dab just a small amount of high temp silicone right at the four corners where the gasket bends over the camchaft journal. Just a small dab at those corners, no more. The cylinder head cover bolts torque at 12Nm As per Honda Marine Shop Manuel.Valve clearance inspection must be performed with the engine cold.1)Remove the engine cover.2)Move the gearshift lever to "N" position.3)Remove the four 6x25mm flange bolts and three 6mm plain washers from the flywheel cover.4)Remove the flywheel cover.5)Disconnect the breather tube and oil return tube from the cylinder head cover.6)Remove the sparkplugs and the engine hanger bracket. CAUTION! .The starter stopper collar is close to the flywheel and the starter ring gear can become sharp. Avoid hand contact with the starter stopper collar or flywheel ring gear.Hold the upper portion of the flywheel when rotating engine..To avoid waterpump impeller damage, always turn the crankshaft in a counterclockwise direction.7)Manually turn the flywheel counterclockwise in the same direction of the arrow on the flywheel. Align the "T" mark on the flywheel with the "I" mark on top of the engine hanger mounting boss. The "Tv" mark on the cam will align with the "T^" mark on the cylinder head. In this position the No.1 piston is at top dead center of its compression stroke.With the engine in this position, check the intake and exaust valve clearances of #1 cylinder by inserting a feelers guage between the valve stem and the adjusting screw on the rocker arm.Valve clearance,Intake 0.13-0.17mm (0.005-0.007in.)Exaust 0.21-0.25mm (0.008-0.010in.) 8)Turn the flywheel counterclockwise until the cam pully turns an additional 120deg. and the "^2" mark aligns with the "T^" mark on the cylinder head. This will put the No.2 piston at TDC of its compression stroke. Check the inatke and exaust valve clearances on the No.2 cylinder.9)Turn the flywheel counterclockwise until the cam pulley turns an additional 120deg. and the "^3" mark aligns with the "T^" mark on the cylinder head. This will put the No.3 piston at TDC of its compression stroke. Check the intake and exaust valve clearances on the No.3 cylinder.10)Proceed to adjustment if necessary or install the removed parts in the reverse order of disassembly.Adjustment 1)With the cylinder at TDC of its compression stroke, loosen the adjusting screw lock nut, and turn the adjusting screw to obtain the specified intake and exaust valve clearance.2)Hold the adjusting screw using a screw driver, and tighten the lock nut.Torque:23Nm (16.6 ft-lb) 3)Recheck valve clearance after tightening the lock nut.4)Install the removed parts in reverse order of disassembly.-------------------------------Checking valve adjustment deserves alot more attention than what brand oil you're using.Valve clearances tighten substantially at cold temperatures. A valve with tight clearances on a 70deg. day is one thing. That same clearance goes away on a 20deg. day. Immediately resulting in a terrible coldstart and rough running while the engine warms up.A common complaint with the BF50.


    • #3
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      Re: bf50 valve adjustment

      I thank you sir, your help is greatly appreciated. You represent why this forum is what it is . Hope I can return a favor back your way some day!