Newb - few questions ..please bare with me

Changed the oil last night and found quite a bit of sludge in the oil filter area . Cleaned out as much as I could ..wonder how the oil got sludgy..only 1687 miles on the bike...It could be the original oil, I'm not sure

Have you got the primary fluid changed yet? I'd also think of swapping brake fluid if it has some years on it. Brake fluid will absorb moisture over time. Usually every second year is a good rule for interval.

Primary? Is that the same as the transmission lubricant?? I have not changed it yet..

Per the harley manual :

"An opening between the primary drive and transmission
compartments allows the same lubricant supply to lubricate
moving parts in both compartments."

thats answers that question..says it take a quart to fill as well... does anyone currently use 20w50 in the trans? I read that harley performance recommends 75w90 in the trans. I am currently running amsoil 20w50 in the engine, would be nice to only use one type/brand of lube in both cases.

I just use H-D primary fluid as supplied by my local dealer. I figure if the engineers that made it recommend it, it is likely the best choice for reliability overall.

yep..i bought a bottle of HD formula+ which is spec'ed out for the trans/primary

im gonna replace whats in the case now with the formula+, then try amsoil 20w50 as its approved for wet clutches..like a before and after comparison. Heres another question..i have the right amount of oil in my bike (3.6 qts) but the oil tank is nearly full to the top when i check it cold..HD manual says you can check it cold ..must be cause the oil hasn't been sucked in yet from running?

I seem to recall someone (Lucifer maybe?), mentioning the 04-05 Sportsters take a wee bit less oil, (2.8-3.0quarts) than the manual calls for. There was a misunderstanding at printing I guess. Also, the oil level should be checked on the side stand on 04 and up Sportys. If they get a bit overfull, oil tends to puke from the breather ports into the airbox when driven with spirit. I run H-D 10w40 dino oil in mine. You should be able to find more info on this on the H-D Sportster forum.

Be careful with recommendations from other H-D owners, as many big twin ideas don't translate well to the Sportster motor when it comes to fluids. Luckily there is a pretty knowledgeable bunch on here, just make sure they know exactly what you have and you will not be steered wrong.

(would have been nice to know! when i bought the bike the oil level was right below the top of the fill neck..thinking the last P.O. was an idiot i pumped it out to the full marks on the dipstick..when i changed oil last it was back to being full to the filler neck..makes sense now!. Now to pump out nearly a quart of $12 a quart oil LOL.

H-D has finally figured out that the 2004+ XL oil capacity is not 3.6 qts as listed in the service and owner's manuals, but is actually 2.8 qts. They issued a tech tip (#312) for the dealers on 6/15/07. (thank you to the dealer who faxed this to me.)

Quote:
2004-2007 Sportster Oil Capacity

Service literature for 2004-2007 XL models incorrectly lists oil capacity as 3.6 quarts (3.4 liters).

The correct amount listed should be 2.8 quarts (2.65 liters).

Oil capacities listed are approximately the amount required to bring the fluid level near the full mark on the dipstick. Refer to the applicable service manual for the complete oil change procedure.

Service Note:
Be aware that the dipstick has a Full mark to indicate the highest level of oil that should be installed in a hot engine and an Add mark to indicate the lowest level of oil in a cold engine. The engine is designed to operate correctly with the oil level in the range between these two marks. While it is most important to not overfill the system, it is acceptable to operate the motorcycle with the oil level anywhere in the range between the Full and Add marks.

You can get away with motor oil in the trans/primary,but it's not the best for it...I leave motor oil for the motor....HD used to say you could run the Syn3 in the tranny too,but stopped saying that because they were showing wear...
The Harley formula+ is made for the trans/primary and it is a gear oil with wet clutch additives...You can use 75-90 or 80-90 gear oil in your Sporty just read the label and if it says "suitable for wet clutches" or "Good for Limited Slip Differentials" You're good to go...Most do but not all,just read the label on back...
Usually when changing the oil...If it calls for 3 qts,I'd put 2 1/2 qts in approximately,run the engine for a minute,shut it down,check the level and then just top it off...

sure enough..its 2.8 qts..not 3.6 of oil...pumped out nearly a quart, then ran the bike down the road for awhile to get it hot, checked it then topped off the oil. all is well with the universe now. the breather definitely soaked the air filter with oil cause of that. yeah i think ill be happy with formula+.. gonna swap out the primary/trans oil tomorrow and see how she likes it.

Try videos posted on Youtube from "Delboy's Garage", pretty good list of how to's on Sportster stuff at times, and recommended fluids and why he uses them.