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  1. #1
    Junior Member

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    May 2012

    Default Whats Better? "Sealed Primary with or stock scavenger oiling system on Shovelhead"

    I have heard conflicting opinions bought with sealed talked into going back to stock expeirenced trouble with pick up final drive
    clearences went back to sealed caught grief with Larry's bike shop for it JP tech said to stay with oiling is stupid. and the of the masses is?

  2. #2
    Senior Member

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    Dec 2017


    There have been a few threads on ChopCult about sealed primary, though not directly related to you question of which way to go, or what's better;

    Gen Shovel primary filling up with oil. need advice

    shovelhead questions
    which includes this post by Misfitcj from Shovelhead.US:

    Shovelhead usa Oil Bath Primary - Sealing your Primary Oiler
    It's easy to isolate the primary, you can do it when the bike is assembled, but a cleaner job can be done by taking parts off (ya' need to pull the inner primary and oil pump to permanently plug the connections off with pipe plugs, but you can get by with just cutting the hoses and inserting a bolt into the hose to plug them off for quite some time until ya' can "do it right" at the next major teardown).

    First I'll explain the hoses coming from the primary and what you need to do to seal it off. There is a 3/8" vent line coming from the middle of the inner primary that "tee's" into the vent line going from the motor case to the oil tank. There is another 3/8" oil return that connects to the rear of the inner primary, near the inside bottom goes from the inner primary back to the motor case, where it connects to a fitting just inboard of the oil pump (near the crankcase vent fitting). And finally, there is a small 1/4" line connected to the top of the oil pump that supplies oil to the inner primary, through a small fitting in the middle of the inner.

    You need to remove the vent line from the inner and plug it off. You will no longer need that "tee" in the motor case to oil tank vent line, you can replace it with a single length of hose. You will need to remove the oil return line from the rear of the primary to the motor case and plug both ends (as stated before, you can simply cut the hose and shove a bolt in each end, securing it with a hoseclamp...this works, but I prefer to use brass plumbing plugs, 1/8" pipe thread, to close everything off. Then, disconnect the smaller oil supply hose at the oil pump. Leave the hose connected to the inner primary fitting. Run the hose down under the frame, so it can act as a vent for the inner primary. If ya' don't vent the primary to atmosphere, as the lube inside warms up the primary will pressurize and oil may seep out of the gaskets. Again, you can plug the nipple at the oil pump by simply leaving a short section of hose on it and plugging it with a screw or you can pull the little nipple out of the oil pump cover by twisting it back and forth with a pair of pliers, then tap the hole for a small machine screw and screw it shut. As I said, while the plugged hose method works, I really hate the look of short hoses plugged with something and it's not much more work to do it the right way.

    Once you have the oiling system disconnected, you need to add oil to the primary. I run straight 30 weight auto oil. Never had a problem with clutches, but make sure you are running a wet/dry clutch...a plain "dry" clutch will act up. As far as oil, it only takes about 1/2 quart or so. Just have somebody set on the bike in an upright position, pour the oil in through the derby cover until it just touches the bottom of the clutch shell and you're set. You don't need to have the chain in the oil, it only needs to be enough oil so it contacts the bottom of the clutch the clutch shell spins, it'll sling the oil around and lube the chain no problem, guaranteed.

    I have set up a few bikes this way and never had any complaints. I have been running it myself ever since I went with an electric start four years ago. It works for me.

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    For those looking for primary sealing information...............from Hawg Ryder on Shovelhead USA

    Sealing up an enclosed chain drive...?
    Last edited by TriNortchopz; 02-25-2018 at 12:50 AM.

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