Carb Screw Seized...

[Guest]

Hi guys,

I took the plunge yesterday and decided to pull the carbs for a full strip down and rebuild on my GS650G Katana. Everything was going to plan, then I hit a bit of a road block. One of the phillips screws has seized on the end of the underside bracket that holds the carbs ganged together. I have tried heat, penetrating oil, gentle persuasion, even gently whispering, everything. I decided to stop so i didn't strip out the phillips screw or worse shear it of in the thread well.

Any suggestions would be welcomed.

Thanks in advance.

J.

[JJ]

An impact driver will work wonders. So will a pair of vice grips, tightened on the outer diameter of the screw head.

[therefinery]

An impact driver will work wonders. So will a pair of vice grips, tightened on the outer diameter of the screw head.

JJ,

I haven't tried the vice grips or the impact driver. I thought if I had used an impact driver it would just strip out the screw head. Very frustrating.

J.

[cowboyup3371]

Like JJ said use an impact driver but don't buy one from Harbor freight as their bits are too soft. Sears sells a decent one for the price. Once you do, socket cap screws are a popular replacement and work great

[Brendan W]

It most likely isn't phillips head but JIS. Most screws get damaged fairly quick using a tool that isn't a good fit, hence, as cowboy said, replacing with capscrews is a popular choice.

[2BRacing]

...... One of the phillips screws has seized on the end of the underside bracket that holds the carbs ganged together.

Although the screws look like the cross-head "Phillips" pattern, they are actually JIS (Japanese standard). Screwdrivers or bits according to the JIS standard have a different profile at the tip and will not "cam out" of the screw head like a normal Phillips screwdriver will.

If they are available in your country, the "Vessel" brand of JIS screwdrivers are excellent. They even have a impact driver that look just like a normal screwdriver. There have been a number of posts here recently on these tools.

[londonboards]

Heat and cool with a blow torch. Get a punch (flat head) and give it a couple of sharp knocks - to break the thread lock. Cut a slot in it with a hacksaw or a dremel. Apply lots of magic solution (50% brake fluid and 50% cellulose thinners) and allow plenty of time for it to soak in.



Then this happens:



So cut another slot:



And so on. See the whole thread here:

Carb Screw Problem


I think you have only just started with this one.

Good luck.

[TiiMuch]

I had that happen on a least of handful of my carb gang screws. And I had the right screwdriver.

I used the thinnest zip cut blade in a angle grinder and just carefully ground a nice slot most of the way thru the middle of the phillips head screw to leave a nice deep slot.
Then used the largest, tightest fitting screwdriver I had, a firm grip and they just backed right out.

I think the grinding could have created a lot of heat in the screw as well and that may have helped in the whole process.

Bought new screws, flat washers at local Home Hardware bolt bin,...they look fabulous.

[JTGS850GL]

If it's only one screw that's stuck, then de-gang the carbs and simply turn the rail counter clockwise while holding the carb body. The screw will turn with it and be loose enough to remove.

[therefinery]

Hi all,

thanks for for all the tips. The gang screws were infact JIS. That was my error. I jut took my time and managed to get there using vice grips. I have to say I've always been a bit wary of the idea of using an impact driver on anything that feels seized. I gave it a whirl on the flips side of the carbs, now I have a new friend. Thought I would have stripped out at least one screw. But made it unscathed.

J.