Topic: Very Stuck bowl drain screws on Carbs, how do I get these off?

[BassHog]

So i have my carbs off of my 72 CB500K2 as it sat for a while and the carbs needed a good cleaning. Everything is going fine but I cannot for the life of me get any of the 4 bowl drain screws out. I want to put new o rings on them and also have the ability to drain the bowls if needed for storage reasons. As far as I can tell these have not been removed in a very very long time. I have tried everything to get them out but I am not having any success. I am just damaging the screws as they are softer than my large screwdriver.
I was thinking maybe and impact driver but my impact drive does not have a bit thin enough to fit the slot.

Does anyone have any suggestions to help me get these out?

[Pielz]

Maybe you could fill the bowls with PB Blaster or something. Maybe heat them up a little?

[BassHog]

Maybe you could fill the bowls with PB Blaster or something. Maybe heat them up a little?

Yeah PB Blaster was going to be my next try, but they have been in there so long I'm afraid it wont do much.
I'm afraid of using a torch on them as all the metal involved is soft to begin with, maybe a heat gun instead.

[Pielz]

Yeah I'd probably go with a heat gun. Or maybe soak them in hot water if you're really worried about it.

[carnivorous chicken]

Heat is the answer. and make sure you are using a JIS screwdriver, not phillips.

[Nurse Julie]

Do you mean the brass float bowl drain screws, if so, a JIS screwdriver will be no good 😊 I have snapped 2 recently trying to get them out, they were stuck fast and just like putty ☹️

[Pielz]

Mine were stuck as hell too. Realized there was a ton of gummy garbage (probably old o-ring) built up right where the tip of the screw seated. Was causing leaks and stuff. Definitely sucked and deformed the flat head side lol. Fortunately I have a new set in the mail.

[BassHog]

Yes, I was talking about the brass ones, I'm gonna try soaking in PB Blaster then some heat gun warming to hopefully pop them loose.

[carnivorous chicken]

Do you mean the brass float bowl drain screws, if so, a JIS screwdriver will be no good 😊 I have snapped 2 recently trying to get them out, they were stuck fast and just like putty ☹️

Brain fart -- thought you meant the bowl screws, not the drain screws. But heat is the key. Even a hair dryer will work.

[b1jackson]

For the sake of a few orings I heat them up good with the torch and basically soften or cook the rubber out. All that varnish and crap settles there too. Then just spin them out.  Maybe use a cordless impact too worse case.

[CaptFatCat]

I had the same issue with my K2 carbs. I carefully heated up the aluminum around the brass plug with a torch turned way down low for a few seconds then sprayed a little WD40 on them and they came right out, Since then I took a wide common screwdriver and ground the sharp end flat for a perfect fit. No more booger-ed up drain screws.

When heating the aluminum try to only heat the aluminum not the screw, heat to the screw will cause the material to expand and it will be tighter not loosened.

Heat and WD40 work well together, its like the wd seeks the heat and penetrates better.

[Redline it]

if the screwdriver slots are getting wasted, parallel jaw pliers, a needle nose vise grips, or channel locks pliers gets them all out, case screws etc. get a good square bite, don't squish too tight and make sure you got room for even only a degree or two. they come out real easy that way. no heat, no pushing a screwdriver into the screw all lined up perfect and then try turning it only to slip out of it again.

[Gene]

if the screwdriver slots are getting wasted, parallel jaw pliers, a needle nose vise grips, or channel locks pliers gets them all out, case screws etc. get a good square bite, don't squish too tight and make sure you got room for even only a degree or two. they come out real easy that way. no heat, no pushing a screwdriver into the screw all lined up perfect and then try turning it only to slip out of it again.

I was going to suggest pliers/channel locks if you can get a grip on the edge of the screw. If they get too chewed up you can get new ones, but at least they're out.

[pjlogue]

Heat and use a flat blade that fits snugly in the slot...along the whole slot!  If the screwdriver twists out and shaves the slot in the plug try using vice grips and a screwdriver.  A heat gun (not hair drier) may work but a propane torch will but you need to be careful so you don't melt the bowl. 

I have done quite a few bowl drains that were cemented in from years of gunk.  Heat usually frees it.  A lot of the screw slots are shaved from PO's using the wrong size screw driver.  If they are real bad the vice grips will work but leaves marks on the plug.

-P.

[Pielz]

Could probably use a rotary tool to regrind the slot for the screw driver. I bet that heat would help free it up too

[PeWe]

I removed the screws on CB750 carbs with help of a vise. Vise squeeze the head of the screw tight, rotate the bowl.