New CB500F owner - with a rust problem - Honda CBR500R Forum : CB500F and CB500X Forums
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post #1 of 11 (permalink) Old 08-30-2018, 09:13 PM Thread Starter
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New CB500F owner - with a rust problem

Picked up a used 2014 today with only 800 miles on it. Looked over the bike, and had a touch of corrosion on some fasteners, light dust and grime, but nothing out of the ordinary. Started fine, tires looked good, had always been kept under cover. It rode fine on the way from the owner's place to my office where it is stored at the moment. While going through it I popped the gas cap (why didn't I do this when I inspected the bike for purchase?) and was greeted with a **** of a lot of rust.

The bike hasn't had the fuel lever recall addressed yet either, and with no local dealer where I am, I'll be pulling the tank to replace that anyway. Where do I go from here? I'm thinking of draining the tank, removing it, pulling the pump assembly out of the bottom and using sandpaper to remove as much rust as possible, then treating it all with Ospho and re-assembling. Is there a replaceable fuel filter somewhere to get at?

Here is a video of the damage.

edit: apparently I can't post links here. Youtube dot com slash dtSFjaSRWcA

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post #2 of 11 (permalink) Old 08-30-2018, 11:07 PM
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The fuel filter is part of the fuel pump unfortunately.

Item #32 in drawing:

A bit pricey and harder to get at then other filters.

But some good housekeeping with the tank and a new filter should work out.

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post #3 of 11 (permalink) Old 08-31-2018, 10:47 AM Thread Starter
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Thanks. I'm going to pull the tank tonight and take a look. It has only done a few miles since sitting and developing the rust, so the filter may not be full of crud (yet). My hope is that the hole for the pump assembly is big enough to get my hand inside to access the rusty spots.
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post #4 of 11 (permalink) Old 08-31-2018, 11:22 AM
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With the fuel pump removed you might be able to get a bead blaster hose into the tank to get the rust blasted off the inside of the top, and through the filler to get it off the bottom. You should be able to find a commercial blasting place if you don't have the equipment.
It will take some thorough flushing afterwards, for sure.
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post #5 of 11 (permalink) Old 08-31-2018, 02:28 PM
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Maybe try some Evapo-Rust. People I know who are seriously in-the-know swear by it. I recently bought some to use with a couple of tanks I have for other bikes, but I havenít tried it yet.

2013 CBR500R - probably up for sale soon - OK, NOT!
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post #6 of 11 (permalink) Old 08-31-2018, 08:47 PM Thread Starter
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Pulled the tank after work today, drained the old gas, didn't even smell like gasoline. Dumped it and rinsed the tank with soapy water, then did a 4:1 water/muriatic acid wash, let that sit for about 20 minutes, rinsed, then added about a 1:1 mixture of water and ospho, will let that sit overnight, then drain tomorrow and let dry. The rust is already gone, only a few specs, but the overnight soak with phosphoric should take care of that. Will also open up the pump assembly tomorrow and inspect/clean.
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post #7 of 11 (permalink) Old 09-01-2018, 02:17 PM
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What the **** does even cause this? Rust on the bike? That's more or less expectable depending on where and how you ride it and treat it - but rust inside a "sealed" part such as the tank? How can this happen?
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post #8 of 11 (permalink) Old 09-01-2018, 03:16 PM Thread Starter
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A few years in hot, humid conditions sitting around unused with a nearly empty tank. Tanks are vented, so moisture gets inside. Without the bike moving around, fuel doesn't get splashed on the bare metal bits to keep them coated.

I rinsed the tank out thoroughly today with water and then alcohol, and topped off with fresh gas. Ran the fuel pump a bit with the outlet in a jug to flush through any crap. It is running now, but will die from time to time. Rocking the bike back and forth a bit will typically get it to re-start. This means there is probably some water still in the tank. I'll add some dry-gas to the tank and run this through, hopefully that clears everything up.
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post #9 of 11 (permalink) Old 04-10-2019, 09:23 PM
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Today's awesome ETHANOL based gasoline are the worst things. ETHANOL attracts moisture....and we all know what happens when water attacks metal....nasty rust! Thank you Federal Government for subsidizing the corn industry and forcing ETHANOL based gasoline into today's service stations.
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post #10 of 11 (permalink) Old 04-15-2019, 10:58 PM
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Get this problem fixed? I thought today’s tanks had some kind of liner in them. Guess not! Sorry to hear your problems.
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