Flushing forks
Any advice? Would there be a problem if one would pour solvent into the fork in order to clean out old oil and other debris before refilling with new oil?
Last edited by Richard Lang; Jan 23, 2019 at 11:13 AM. Reason: add word
I wouldn't, there is the possibility of damaging the seals. If the oil that came out is so dirty and contaminated that the forks need to be flushed, it's time to do a full disassembly and rebuild on them with new seals or install a monotube kit at that point.
There is a multitude of threads describing the fork service process as well as YouTube videos. If you want to clean out the inside of the fork tubes why not disassemble them? Personally I that is what I would do vs pouring solvent into them as I would be concerned about the residue of the solvent and the effect it may have with seals, etc. You didn't state the year/model of your bike, however, one of the benefits of disassembling the forks is doing upgrades such as progressive springs, etc. You can also replace the seals and be good to go until the next service cycle as described in the Service Manual!
You could always do a couple of quick fluid changes, but if it's that dirty or was leaking i would pull them apart and install new bushings and seals and have new forks again. Then don't wait so long between fluid changes.
You may be surprised how much yuk accumulates in the fork sliders, after a decent mileage. The only effective way of cleaning it out is to dismantle, as already suggested. Depending on your current mileage also consider changing the bushings and seals.
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If it'll make you sleep better, pour some clean fluid in to rinse it before you put the plug back in. But it's really not accomplishing anything.
One of our 'engineers' claims that he runs one quart of clean oil through his engines before replacing the drain plug. He's a putz.
One of our 'engineers' claims that he runs one quart of clean oil through his engines before replacing the drain plug. He's a putz.
Don’t do that, you’ll never get all the solvent out and it could cause a hazardous situation down the rode. Your suspension is nothing to play games with. If it’s that dirty, disassemble, clean and rebuild. Otherwise, drain, refill and ride.
Thank you to all who responded to that thread re: Flushing forks with solvent. To make it clear as to why I ask these questions: I just bought this bike, a 2006 Electra glide ultra classic with 44k miles. It's a beautiful looking machine, absolutely NO road rash, but I have NO maintenance history on it. I have not yet ridden it, as a matter of fact, I have never ridden a motorcycle before, but have already done a compression chk,, done a borescope inspection, replaced plugs, engine oil, trans oil, primary oil, adjusted final drive belt, adjusted primary chain, serviced shocks, replaced frt & rear brake pads, changed brake fluid, & now am looking at the forks. Your sage advice has been utilized where applicable, & again, thank you to all. Ric Lang..........PS As I mentioned in earlier thread, I'm an FAA aircraft/engine wrench, so that's why all this manic stuff is going on.










