Checking the oil level on your Harley Davidson motorcycle is a must before trips and between service. Many folks ask us what the best way to check it is, and how often.
On older motorcycle that use oil between service, we suggest every 500-1000 miles. On new motorcycles like the TC88 models it's not unusual to go the full 2500 mi. between service without using any oil, but it's still a good idea to check the level before trips just in case.
On models like the Softail and early Harley Davidson's with a wraparound oil tank, it's important not to overfill because the breather line from the engine can become submerged in an overly full tank. This can cause oil to run into the breather tube and down into the cam cover. Oil can then be blown out of the air cleaner or out underneath the motorcycle which is aggravating to say the least. On Softails and wraparound tank models I like to start the motorcycle for a minute and let it idle straight up, turn it off, then standing the motorcycle upright before checking, making sure there is at least an inch of air space below the top of the tank. It is also important on Softails and sporties to idle the motor in an upright position for a minute or two to scavenge the oil from the sump or you will over fill it for sure.
On Softails this is about even with the lower edge of the fill spout. Modern bikes have a marked dipstick in case you can't see inside, but make sure to wipe it clean before you check to get an accurate reading, inserting it fully and removing to check. Checking trans and primary levels is easy as well, but the same theory applies.
Make sure you stand the motorcycle upright and have someone hold it for you if your bike isn't the type checked on the stand. Check the level on the trans with the dipstick on 5 speeds and don't overfill. Overfilling will cause oil to blow out the breather vent hose. On earlier 4 speeds the trans fluid level should be up to the check sight allen in the kicker cover, or on early motorcycle models without this feature it should be up to the threads on the filler cap. On 5 speed primaries, we usually check and fill through the derby cover making sure the fluid level is about to the bottom of the clutch basket. This assures oil will be slung by the starter ring gear on the chain and sprockets. Clutch derby o-rings are usually good for a couple of times on and off, it's a good idea to have a spare in case you have to check primary fluid on the road.
Keep an eye on your fluids and you'll have many trouble-free miles ahead!