I have a 20012 XL1200C sportster. Didn't start it up for a month or 2. When I did try to start it would not. The oil light was also on. So I thought I need oil. Put in 2 quarts until it registered on the dip stick. Then it started up. Next thing I heard and saw was a quart of oil blowing out a hose next to the fill tank. I drained all the oil, out in fresh oil and filter. Started up but sounds different now. Slight change in the sound bothers me, but it seems to run fine.

 

Low oil shouldn't keep it from starting. Check the oil after running the engine.

 

The bike starts ok now, after I changed the oil completely. But when I start it up now the bike just doesn't sound the same as before. The sound is not as smooth as before, slightly rougher.

 

clean or replace air filter and plugs for starts... then just run it for a couple hundred miles and see if smooths out

 

Read your owners manual! If you don't have one check the H-D website and the Owners tab, where you may be able to download a copy. Do not top up your oil, or check oil level, until AFTER running the engine! Put in a set of ear plugs and go for a decent ride. It will probably be fine.

 

What are the consequences of running an engine with too much oil? I remember years ago being told that running an engine with too much oil is actually much worse than running it with not enough oil. Old wives tale?

 

In the case of a recent Sportster, like the OP's, some of the oil 'disappears' when left to stand for a while. Adding oil, then starting the engine risks over-filling the oil tank - messy!

Our bikes are all 'dry sump', so while running they have very little oil inside them, however especially on older bikes with a remote oil tank the non-return valve, which stops oil draining from the tank into the engine, can fail, filling the crankcases. Trying to start an engine in that condition can indeed have serious effects. That cannot happen with more recent big twins, with the oil tank under the transmission.

Hope that helps!

 

I changed the plugs and oil filter and rode for at least 100 miles, no change. I met a retired Harley mechanic yesterday by chance. He said the breather valves are plugged up with oil and need changing or cleaning. He said not to ride it that way, it can cause further damage. Internal plugs or seals could leak due to pressure buildup.

 

on the old irons with the transfer valve, when the thing wet sumps, most of the oil went into the primary, there is a level screw where you can drain it and then add back to bag. on the newer engines, it will fill the flywheel/cam case as the are in common. if there is some oil in the bag, starting at slow idle with machine upright level will let the scavenge pump send it to the bag, do not rev the engine as the rod assy will be going through the oil, this will froth the oil and adds resistance to the turning assy. however, this will do no harm. now if there is zero oil in the bag, then you either drain via cracking the cam case or adding a little oil to the bag and then remove some as it pumps back. TOO bad they got rid of the c/c plug, even the tc has a case drain.
perhaps there is more oil still left in the c/c. might want to check primary for level to see if the crank seal allowed oil to pass through if it got high enough, high oil here will cause a diff sound.