Just changed the oil and was about to pull out of my driveway when I heard a pop and oil began pouring out of the left side of my oil tank right under the seat. The seam on the tank separated and the oil tank is obviously shot. What would cause this? When I checked the oil before changing it, it was low and there was barely a drop on the dip stick. I followed the manual and drained all the oil from the plug from the tank. Only about 2 quarts came out. I figured since it was low on oil that that was all that was in there. Is it possible I over filled it causing the tank to blow apart. I only added just over 3 quarts as the manual indicated? I started the bike prior to this happening and then checked the oil and the level was where it needed to be, all the way to the top mark on the dip stick?? I even let the oil drain from filter and tank over night to make sure it was all out when I changed it. Is it possible that I did not drain all the oil out and the pressure from to much oil blew the tank? Time to open up the wallet again. Nothing like watching $50 of brand new synthetic AMS oil dump all over your driveway!! F**k im pissed

 

Not sure what would cause the tank to separate, perhaps it was defective, but the oil on the dip stick should be 1/2 - 3/4 between the add (bottom line) and the full (top line). What year and model do you have?

 

2007 1200c. I had the bike in my living room and started the bike inside while my wife was gone and even checked the oil and it was to the top line on the dipstick after running it to move the oil through. I followed my manual. Its a damn good thing the tank didn't blow apart while it was in my house, my wife would have murdered me in my sleep. This is going to be an expensive fix. $250 for the new tank and then more oil. What a nightmare! Wondering if there are any aftermarket tanks available. I would like to avoid purchasing anything else from Harley. It has been a long expensive season.

 

Definitely a costly fix, but at least you will survive to live another day since it happened outside. Look on the bright side...at least it happened at home. You could have been far from home and stuck in the middle of nowhere. Perhaps others on the forum can provide insight into your tank issue.

This is what Kevin at DK Customs said about oil level on another thread:
Regarding oil levels, here is what it says in the HD manual that comes with every bike-

"The correct oil level should register midway between the FULL and ADD marks on the dipstick.

If oil level is at or below the ADD mark, add only enough oil to bring the level to the middle of the two marks on the dipstick."

Yes, this can be confusing because it is easy to think of the top line as Full, and on some models the top line even says Full. But HD has been putting out confusing info for decades. lol

The top line is there to let you know if you go over it, you are going to have problems from too much oil being in the system. The bottom line is there to let you know that if it is below that, you are going to have trouble with too little oil being in the system. The HD manual, and experience, shows that between the bottom line and the middle is the best level to run at.

If it was not, then the manual would say if it is at the middle of the two marks, then add enough oil to bring the level to the top line.

 

You're not the first. It was a known issue and tanks were replaced under warranty, without question. That doesn't help you, though. One explanation, discussed years ago, was a frozen/blocked vent. There have been a few threads about it, over the years. Like, this one:
https://www.hdforums.com/forum/sport...k-leaking.html
I usually put some oil in the new filter before installing it. Then add two and a half quarts to the tank. Warm up the bike and check the level. The half-way mark on the dip stick, works for me.
Totally sucks. Check around for prices at discount online dealers. Other than going full-blown custom, I don't think there's an aftermarket replacement.
EDIT: I don't think you did anything overtly wrong. However, don't pour in a full 3 quarts from the get-go.

 

i was just about to post that, lol. there's no pressure release valve on the tank from those years. mine failed slowly over time then suddenly went postal.

the part (62888-04B ) costs around 180, search that part number. install took me an hour or so but, i had been pulling the bike apart so i could replace the tank as soon as the new tank appeared.

i feel like i did a fair job of writing it up, but please feel free to ask questions. i'll help as best i can.

it's f'd up that harley didn't recall or offer good will replacements outside of warranty. it's an oem defect.

 

not costly at all. easy too. literally a bolt in/crimp job.

 

LOL I guess costly is relative especially since it is money you didn't have to dish out if the tank was not defective.

Was that oil tank defect applicable to all sportsters or certain years/models?

 

cHarley and HarleyScuba know that stuff, but whichever sportys got the "A" version of that tank [62888-04] can possibly have the issue. Harley knows about it... i guess it just didn't kill enough people to matter. it cost me tons of money in oil. before i knew what the real issue was, i though it was normal to loose a qt. of oil every 500 miles. i was used to just buying oil like gas. the tank had been seeping since i got it i think. never knew why i lost oil.. there were no signs of leaks. after the fix, it holds the oil. no more wasting money in oil. that alone covered the fix, lol

 

From what I can tell, it was superseded to the "B" version around '08. Most likely, by the '09 model year, I'm fairly sure the tank was the new version. I don't know for certain. I only came across a couple of these during my time as a Parts Department Manager in '07-'08. The first one I encountered, I remember them being on back-order. Probably, the new tank was being produced and hadn't hit the pipeline, yet.
The first one I encountered (thought it was a freak occurrence, at the time), the guy was so cool and patient waiting for his new, warrantied tank. He wanted to give his gal, who had flown in from Europe (Belgium, IIRC) during his temp assignment in the D.C. area, a ride on his Sportster. If it had been up to me, I would've given him one off a bike on the showroom floor (no way that was gonna happen). I felt so bad for him, I offered the use of my personal Sportster for a couple days. He declined, and remained a customer for the rest of his stay in the area. Totally mellow dude. He was probably some sort of Secret Agent, or something.
EDIT: that's a real nice write up, cvaria.