Vaporlocked fork tube?

[OldGoldie]

I think I vaporlocked my left fork, if that’s even possible. Was trying to change the fork oil, but also wanted to flush the old grime out. Drained them but hardly anything came out. Filled both forks with about 9 oz of atf, pumped the forks a bunch of times. Went to drain. Right fork drains just fine, hooked a bicycle pump up to the air valve and pumped some air in with the drain tube open, drained just fine. Put the drain plug back in and went to drain the left fork, no atf comes out. Hooked the bicycle pump to the air valve and hardly any air will go in. Remove the pump from the air valve and what little air pressure built up will release. There is one thing I did notice. I had the valve core removed and I went to pump the forks and some atf shot out through the air valve. I then hooked some pvc tubing up to the air valve and bled out as much atf as I could by pumping the forks, but it was very little. I’m wondering though if I got a hand operated siphon pump if I could continue pumping the excess atf out through the air valve. Has anyone experienced or heard of this before? Am I missing something?

[Rambozo]

Did you try poking a stiff wire through the drain hole to open a passage in the gunk?

[OldGoldie]

I didn’t think about that. I’ll give that a try tomorrow night.

[joecoolsuncle]

i would pull the fork leg apart. if it has that much gunk, it will restrict the damping holes also. where did the gunk come from? worn bushings and powdered aluminum?

[OldGoldie]

i would pull the fork leg apart. if it has that much gunk, it will restrict the damping holes also. where did the gunk come from? worn bushings and powdered aluminum?

I have no idea. I just got the bike a few weeks ago. Haven’t ridden it yet. Too cold where I live. I’ve just been working on installing bags, trunk, fairing, few other things, knew fork oil needed changed but never got round to it. Not even sure it’s gunk plugging it up. Think I’m gonna see what I can do to get whatever oil I can out of it, then flush the fork tubes with gasoline.

[OldGoldie]

So I wasn’t able to clear whatever it is that’s keeping the fork from draining through the side drain hole, so I jacked the bike up and got to the bottom drain bolt, and drained the fork. I replaced all drain bolts on both forks and put about a cup and a half of gasoline in each fork. I’m going to let them sit overnight and drain them again when I get home from work tomorrow night. I might let them sit another night for the gas to evaporate, then fill with oil after that.

[WingAdmin]

So I wasn’t able to clear whatever it is that’s keeping the fork from draining through the side drain hole, so I jacked the bike up and got to the bottom drain bolt, and drained the fork. I replaced all drain bolts on both forks and put about a cup and a half of gasoline in each fork. I’m going to let them sit overnight and drain them again when I get home from work tomorrow night. I might let them sit another night for the gas to evaporate, then fill with oil after that.

I usually use brake cleaner for that. Much better solvent than gasoline, and more volatile, so it evaporates faster, with no residue.

[OldGoldie]

So I wasn’t able to clear whatever it is that’s keeping the fork from draining through the side drain hole, so I jacked the bike up and got to the bottom drain bolt, and drained the fork. I replaced all drain bolts on both forks and put about a cup and a half of gasoline in each fork. I’m going to let them sit overnight and drain them again when I get home from work tomorrow night. I might let them sit another night for the gas to evaporate, then fill with oil after that.

I usually use brake cleaner for that. Much better solvent than gasoline, and more volatile, so it evaporates faster, with no residue.

Had the gas on hand, and I’m not sure how many bottles of brake cleaner it would take to fill both forks to the level I wanted, and how much time it would take to hold the nozzle till each bottle emptied. Brake cleaner probably would work good if I could get the nozzle closer to the dirty parts, especially the clogged drain bolt. Idk if the gas will clean the clog or not, but figured it’s worth a try.

[OldGoldie]

So I drained the gas out and did an alcohol flush next, poured alcohol in the forks twice and let it sit for a little each time, first time came out almost clear, second time completely clear. Gonna let it sit overnight so the alcohol evaporates completely, then put everything back together and fill the forks with fresh atf. Thinking about doing this once a year so it’s easier to flush. Thinking from now on, I might just flush with alcohol since it won’t be nearly as dirty if I do it once a year, and since I’m a barber it’s easy to get ahold of large quantities of alcohol. Barber supply guy comes to our shop every three weeks.

[LAB3]

So I drained the gas out and did an alcohol flush next, poured alcohol in the forks twice and let it sit for a little each time, first time came out almost clear, second time completely clear. Gonna let it sit overnight so the alcohol evaporates completely, then put everything back together and fill the forks with fresh atf. Thinking about doing this once a year so it’s easier to flush. Thinking from now on, I might just flush with alcohol since it won’t be nearly as dirty if I do it once a year, and since I’m a barber it’s easy to get ahold of large quantities of alcohol. Barber supply guy comes to our shop every three weeks.

Considering how mindful most people are about fork maintenance my guess is it's never been changed before. Checking it out in a year will more than likely show clean fluid, especially if you put in fresh fork seals.

[OldGoldie]

So I drained the gas out and did an alcohol flush next, poured alcohol in the forks twice and let it sit for a little each time, first time came out almost clear, second time completely clear. Gonna let it sit overnight so the alcohol evaporates completely, then put everything back together and fill the forks with fresh atf. Thinking about doing this once a year so it’s easier to flush. Thinking from now on, I might just flush with alcohol since it won’t be nearly as dirty if I do it once a year, and since I’m a barber it’s easy to get ahold of large quantities of alcohol. Barber supply guy comes to our shop every three weeks.

Considering how mindful most people are about fork maintenance my guess is it's never been changed before. Checking it out in a year will more than likely show clean fluid, especially if you put in fresh fork seals.

I did not change the seals, since I opted not to remove the forks from the bike. Just cleaned out the best I could while on the bike.