Acetone and Carb Parts?!

[Crotch Rocketeer]

Hi all. I rebuilt my carbs and they were sitting around for a few days so I blasted them out with brake cleaner (it was what I had on hand) before I mounted them. I then spent the next several hours trying to get my bike to run to sync the carbs but it was acting like it was starved for fuel. I finally decided to pull the carbs back off and check the floats. What I found was swollen needle valve points and float bowl gaskets. WTF? The points are so swollen that fuel isn't getting by regardless of float level.

The brake cleaner's only solvent is acetone. I compared it against an empty can of carb cleaner and the carb cleaner has acetone, toluene and methyl ethyl ketone. So what gives? Defective carb kits or chemical reaction that has ruined the carb parts?

[arsenic]

YOU'RE NOT SUPPOSED TO PUT O-RINGS OR RUBBER GASKETS ANY WHERE NEAR CARB CLEANER. Repeat, YOU ARE NOT SUPPOSED TO PUT O-RINGS OR RUBBER GASKETS ANY WHERE NEAR CARB CLEANER. Don't you think there is a reason you have to tear them apart before you spray crap at them?

[scottynoface]

Lol oops.

[arsenic]

Defective carb kits or chemical reaction that has ruined the carb parts?

That one.

[Kreylyn]

Well, on a more positive note... it's possible that if you didn't actually damage the rubber parts, just made them bloat... that you can leave them out in the air and allow for the chemicals to evaporate. They very likely will return to normal size and work again. Unless some of the rubber was actually disolved.

May take a couple of days, but...

Krey

[hardlydangerous]

hydrate o-rings and rubber with solvents and you have a 50/50 chance they will go back without damage....

let it sit in a warm area or in the sun to dry for a day and then check them out

[mammut89]

what about just buying new orings and gaskets . even if you get it to work now they will have drastically reduced the lifetime anyway and are going to make strange stuff happen inside your carbs in the near future anyway. so fix it the proper way the first time is my oppinion

[Crotch Rocketeer]

I looked at my needle valves again this morning and they had shrunk down quite a bit, but still not right. I'll set them someplace warm and see if it speed things up. I realize that this may leave me with compromised parts but I just can't bring myself to pay out another $80 and wait 3-4 days for more kits. I just wanna ride dammit! If I have to kit again later, I can deal with that.

I have o-rings and my old float bowl gaskets are ok. Needle valves are the only specialized part I can't come up with (my old ones were leaking which is why it kitted the carbs). Is it possible to pick up needle valves by themselves?

I had always heard that you aren't supposed hit non-metallic carb parts with solvents but in my years as a home mechanic I had never seen anything like this happen, so I quit worrying about it. "Experience is the best teacher, but tuition is expensive." Not sure who said that but it is true.

[arsenic]

not for under $50 bucks each. The o-ring on them is easy to replace though. You can pick up a set of 100 from Grainger for like $12 bucks

[Crotch Rocketeer]

I've done some more reading on this topic and it is interesting. Some people advocate adding acetone as a fuel additive because it helps fuel vaporize better, thus increasing fuel economy. It seems to take very small quantities (something like an ounce in five gallons). However, it is known to cause swelling in certain materials (usually porous, rubbery ones like o-rings) that are used in fuel systems and can be fatal to some fuel injectors. Nonetheless, acetone is found in certain fuel treatments such as Berryman's fuel injector cleaner.

What it boils down to is that I think I got in trouble by using brake cleaner, which is almost pure acetone, instead of another product in which acetone is only a small part. For example: Berryman's carb cleaner and Berryman's fuel injector cleaner are the same chemical, so Berryman's carb cleaner shouldn't be harmful to carb parts even with its small acetone content.

[arsenic]

No, Berryman's isn't. To make the diaphragms bigger again, in the case that they've shrunk. I put them in a butter dish full of spray carb cleaner for like a minute. And that does it, if I leave them in to long, they get too big and I gotta wait for them to shrink. Which takes forever. But if I soak them in Berryman's chemdip, it doesn't make them bigger at all.

[scottynoface]

Remember that there is pretty much no rubber in a fuel injected system besides the hoses...