What is the "standard" time / mileage for changing the Primary Oil? It appears there are a lot of choices as to what to use. I guess I will use Mobil I 20-50.
Just go by the owner's manual. The primary oil change is the least critical of the three holes. The primary oil is nothing more than an oil bath to lube the chain. The product used in there doesn't have to be that high tech. Some guys use ATF, some regular motor oil, some high buck stuff.
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2000 Road King Classic. Andrews 26G cams, SE Stage I, DFO, V&H True Duals with Samson Fishtail Mufflers.
I've been using the HD stuff, though I have been looking for a cheaper oil that does the same job...another thread suggested Drag Specialties stuff, supposed to be just as a good, buck and half less. I change mine every 5K as scheduled in the maintenance manual when I change all the others.
Change it when you do the engine oil, it's only less than one quart in the primary. Most any 10/30 or 10/40 NON synthetic oil will work well in there. Synthetics can cause some clutch slippage.
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Don't take life too seriously, no body gets out alive.
ORIGINAL: xxxflhrci...The primary oil change is the least critical of the three holes. The primary oil is nothing more than an oil bath to lube the chain...
I don't agree with that.....Of the three fluids I would put the primary at number two behind the engine oil. Once the tranny has 5000 miles on it, you pretty much can ignore it...If you are looking to limit cost on fluid changes. Run a decent synthetic oil in the tranny once you've got 5-10k on it, and change it out every 10K or so. Again, this is if you're trying to limit cost. My tranny goes every other change because I was using semi-syn oil in it. I've since swapped to Mobil 1 75-90, so I'm gonna increase the change interval to every third or fourth oil change. I do notice a small change in noise levels with the Mobil 1 over the HD semi-syn oil.
The primary 'oil' also bathes the clutch and regular changes helps flush out any crap from the discs. And different models require more (or less) oil. My 93 Evo Electra Glide uses 42-44oz in the primary. I 'normally' change the primary oil when I change the engine oil (somewhere around 2500-3000 miles). But on occasion will go every other engine oil change, depending on how I racked up the miles. I'm presently using Formula+ in there after 47,000 miles of regular HD Primary oil. I don't notice much difference between the two. I just might experiment with a synthetic once I use the last of the Formula+ I've got on the shelf. But I'm also looking at cost and not having to 'stock' a bunch of different oils, so when I swap the motor (just got the top re-done) over to Mobil 1 V-Twin, I might try it in the primary also.
Primary Oil Change
