Screws stripping on diaphragm caps

[gitarooman83]

I was attempting to rejet my 2009 gs500f today and everything was going well until I attempted to take off the diaphragm caps on the carbs.  The screws are apparently extremely tight and while attempting to remove them, I stripped 2 on the one carb.

I used a hacksaw blade on the one screw to notch it so that I could remove it with a flat-head, but still no luck.  Sprayed with wd40, let soak in, still no luck.  I completely removed the carbs but I'm hesitant to try anything further as I don't want to completely destroy the screw. 

I suppose I'll take it to the Suzuki dealer on tuesday unless anyone on here has any suggestions as to how I go forward with this.  I'm just kind of shocked that the screws are so tight from the factory.  There's got to be something I'm missing.. right?

[Big Rich]

WD-40 stands for "water displacement", it's not a penetrant. Get some pb blaster, aero kroil, or even some atf mixed with kerosene.

Have you tried a impact driver? They are about 20 bucks at Auto Zone and make quick work of non-stripped heads. Or if you have a Dremel, cut the sides of the head flat so you can get a pair of pliers on it.

[gitarooman83]

So I just did some searching and found that this topic has been brought up before.  Apparently a JIS screwdriver is needed to properly remove the screws.  I can't seem to find one around here at any hardware store.  The Suzuki dealer may sell them or at least be able to unscrew the screws.

I tried using vice grips and was able to get one of the screws out, but it's stripped pretty badly.  Does anyone know what thread count and screw length the screws are?  I'm thinking I could take all of the screws out with vice grips and then replace them with philips head screws since I'd rather not put the stripped screws back in, not to mention I may strip them worse on the way back in. 

Any help would be appreciated.

[RichDesmond]

This is what you need:

http://www.mcmaster.com/#jis-%28japanese-industrial-standard%29-screwdrivers/=c7zrib

I recently got the three piece set at the bottom of the page, very happy with them so far.

If visegrips and/or cutting slots don't work you can always drill the heads off, remove the cap and then use vicegrips on the stubs. Or try an EZ-Out, although you have to be careful with those.

Once you get them out, if they are plain screws take them down to the hardware store and get Allen head replacements. If they're shouldered though you will probably have to get OEM replacements from Suzuki.

[plewis51]

Or drill em out and get socket Head cap screws. 5mm i think? After my rejet the socket heads are a blessing! I have been in/out of the carbs a hand full of times to tweak the GS.

[k.rollin]

Slot or grind all of the screws with a rotary tool or hacksaw and remove them with a flat head screwdriver. Go to the hardware store and replace all the JIS screws with socket head cap screws. You'll need these:
    4 x M5x12mm
    10 x M4x10mm

[the mole]

+1.
I've had some luck in getting these screws out (with a phillips driver) by supporting the carb carefully and whacking the driver with a hammer. This helps turn the JIS heads into "phillips" and the impact helps free the screw. Don't try this without a degree in mechanical butchery.

[plewis51]

Slot or grind all of the screws with a rotary tool or hacksaw and remove them with a flat head screwdriver. Go to the hardware store and replace all the JIS screws with socket head cap screws. You'll need these:
    4 x M5x12mm
    10 x M4x10mm

[5thAve]

I stripped most of mine when opening the carbs for the first time. What a pain.  Congrats on figuring out that JIS spec is NOT the same as Phillips.   

grind or slot them and whack them out with an impact driver or drill them or whatever. Just get them out. Then go to the hardware store and replace them with a handful of metric socket-head bolts. Cheap, easy replacement, and you'll never have this problem again. 

[The Buddha]

Those bl00dy screws are one PITA ... Stripped many, drilled out many more and of course they will not be the last ... Be a bit careful drilling em, you need plenty of coolant, if you get it hot, it will melt the plastic. And what sorta fool tightens a screw to 300 lb ft when its holding down plastic.
Cool.
Buddha.