Stripped carb boot screw

Got three off no problem. Then the fourth slipped right as it started to turn and bam, stripped. There is a small amount of grip but then the screw starts to cam out. I don’t want to make it worse, so what next?

It looks to me like you tried to removed the screws using a Phillips screwdriver. They are NOT Phillips screws, they are JIS (Japanese Industrial Standard) and Phillips screwdrivers will not fit the properly (see images below). If it was mine I would first soak that screw with Kroil for 3 days. Kroil will break the bond between the screw and the cylinder head. While it is soaking I would buy or make a JIS screwdriver tip. The tip should fit perfectly, otherwise the odds of the screw coming out are very slim. Ed

Pick up a hand impact driver, Use the best fitting bit, Tap on the bit to clean up the slots then drive it out. If you have to take out the air box then do it.
Steve

SWest wrote: Pick up a hand impact driver, Use the best fitting bit, Tap on the bit to clean up the slots then drive it out. If you have to take out the air box then do it.
Steve

I picked up one of those *mumble* years ago, and love it. It's the kind of thing that if you need it, you need it.

The drawback in this situation is there may not be enough room to get the impact driver in there straight and centered and still get a good whack at it with a hammer. I have a twin (440) with the same issue, and right now I'm just planning to pull the engine because there's no room to operate.

I have been soaking with liquid wrench for about 5 days (4 applications over that period). Also used a vessel JIS #3. Photos attached. I definitely don’t have room for an impact driver without taking the air box out. How hard is that? Any other tips?

I never attack those screws without a hand impact. I reinstall them the same way. Taking the airbox out shouldn't be that difficult.
Steve

ERIK814 wrote: I have been soaking with liquid wrench for about 5 days (4 applications over that period). Also used a vessel JIS #3. Photos attached. I definitely don’t have room for an impact driver without taking the air box out. How hard is that? Any other tips?

In that case you have been taking the correct approach. Maybe removing the airbox will help. On my KZ650 that was pretty easy once the carbs were removed On mine there were 2 screws (one on each side of the airbox) that were sort of hidden behind the side covers. Ed

Use some needle nose vise grips! Seeing you soaked it. Or use an impact!
That's an easy one!

Vampliers should work. They're also sold under the brand name Engineer. Anyone who appreciates fine quality tools will be pleased with either. We bought the three piece Vampliers set, but this individual plier should work for that screw.

www.amazon.com/Vampire-Professional-Tool...VT-001/dp/B006YJKAPQ


Good Ridin'
slmjim & Z1BEBE


Good Ridin'
slmjim

Did you get the bottom screw out. If so you may be able to drive the flange to the right to loosen the screw.
Steve

slmjim+Z1BEBE wrote: Vampliers should work. They're also sold under the brand name Engineer. Anyone who appreciates fine quality tools will be pleased with either. We bought the three piece Vampliers set, but this individual plier should work for that screw.

Just ordered 'em. If they work I'll owe you at least a beverage or two.

The PO of my 440 said there was an intake leak so he used what looks like a full tube of silicon to try to seal around the boots. I'm replacing the carbs and the boots and removing the airbox, so the only real concern is getting the boot screws out without jacking up the head.

Cut a slot with a Dremel and use a straight screwdriver ( helped by vice grips on the shaft ). Impact driver would be best though.