How to adjust your GXH50/Huasheng/Titan valves

Discussion in '4-Stroke Engines' started by The_Aleman, Jul 9, 2012.

  1. The_Aleman

    The_Aleman Active Member

    On the other forum I was asked how to adjust the valves on a Huasheng. So I wrote up a procedure, perhaps it can help someone here, too.

    Tools you need to do the job:

    Feeler gauge set with .004" (0.1MM) and .006" (0.15MM) blades. If you don't have one, this is a great set that I use.
    8MM wrench, small flathead/slotted screwdriver
    Recommended: 5/8" spark plug socket, ratchet for that socket, and a straw. Coffee straw, drinking straw, doesn't matter.

    Your engine must be "cold" for this procedure. I set my valves after my engine has sat overnight.

    1a) Remove the 4 bolts on valve cover with the 8MM wrench. Carefully lift the valve cover off the engine. The objective is to not stress the valve cover gasket.
    If the gasket sticks to the engine, that's okay, just leave it there.

    1b) Recommended: Carefully remove spark plug boot and then remove the spark plug with the 5/8" spark plug socket.

    2) Now you have to find TDC on the compression stroke. If you're not familiar with each stroke on a 4-stroke, I've attached an image that should help. Take a good look at the valves while slowly pulling on the pullstart a few times. You need to adjust the valves when both valves are fully closed, and this only happens at Top Dead Center of the compression stroke. The valves are closed for the longest amount of time between the start of the 2nd stroke and the start of the 4th. Insert the straw into the spark plug hole and find TDC. The straw will be at it's highest point and there should be play in both valve rockers. If there's no play, they are set too tight.

    3) On each valve rocker there is a slotted stud with a nut on it. Loosen the nut on each rocker with the 8MM wrench. The rocker closest to the exhaust is the exhaust valve, and the rocker closest to the carb is the intake valve. Use the feeler gauge and the screwdriver on the stud (loosen the nut as needed) to set the clearances. A proper setting is when you feel a light drag of the blade as you pull it through the space between rocker and valve stem. When you have the clearance you need, hold the stud's position with the screwdriver and tighten the nut about wrist-tight. Repeat for other valve.

    4) Put the plug back in and the valve cover back on. Don't overtighten the valve cover bolts, they only need to be snug, about halfway between thumb-tight and wrist-tight.

    Now take her for a good ride! :grin5:

    Attached Files:

    skweezit likes this.

  2. 2old2learn

    2old2learn Member

    You take me back almost 45 years to my early teenage years when I rode motorcycles and would adjust my valves on my Honda 125 scrambler. Wiped it out in a curve down in Mississippi by shooting the curve and snapped the front fork and threw me into an inclined bank where I decelerated from 55 to zero in one second. Broke my pelvis just to right of center from top to bottom, in half. I could stand on one leg and the other leg was 4-5 inches off the ground. My only choice was to move to mountain country so my injury made me fit the terrain! Been in Arkansas ever since.
  3. KCvale

    KCvale Motorized Bicycle Vendor

    Nice tutorial ;-}
  4. 2old2learn

    2old2learn Member

    Just got through adjusting the valves and they were a bit tight. Didn't have a gasket just some silicone sealer. About to run to the store and pick up some gasket material and make me one, the old school way! The valves on this motor were a bit different from your description, but my old Honda 125's were just like you described. These had an Allen wrench female head and a small nut on top you had to loosen to adjust and then tighten the nut back. Same basic process though. Thanks for your help guys.

    Back in 1971 they didn't do invasive surgeries like they do now, they just prescribed bed rest to allow my muscles to pull the pelvis back in alignment and self heal. So good! Though I suspect I have a little arthritis in that area that bothers me a little but if I'd known I was gonna live this long I'd a taken better care of myself! Sadly to say, I've already outlived many of my long time friends and they haunt my nights in the twilight hours.