Carb Spacer - screw head

[Mikep328]

I have new carb spacers/insulators that I figured to install while I have the carbs off but when trying to remove the original screws (with proper JIS screwdriver) , I buggered the slots in the head on the bottom screw of the first insulator.  Top screw came out OK.  Any thoughts on how to remove that screw ( and probably others)?

Obviously I could just put the other screw back in and forget about changing them but I'd prefer installing the new insulators as planned.

[McCabe-Thiele (Ted)]

I had a similar nightmare in 1964/5 with JIS screws on a 250 Dream case cover.

On some I was able to make a saw cut & use a big scredriver.  Due to the recess I ended up having to use a small chisel to get some to move, a couple ended up having the heads drilled out, luckily when I finally removed the case I was able to use a stud extractor to remove the headless JIS screws.
No dremels back then.

I guess access isn't easy - someone here might know of a special tool that works?

[Mikep328]

I've used impact drivers before - the type you hit with a hammer - and they work quite well but there's no room to swing a hammer for these screws!

[Orcade-Ian]

Mike,
Many of us have had this problem and as Ted says some resort to sawcuts, drills, dremels and the like.  I've had to use some or all of those methods in the past but have discovered over the years that the reason for them resisting most attempts at removal is not that they are seized by the thread but by the larger area of contact under the head.  My usual 'go to' method is to take a 3/8 punch and strike the head from as many directions as available - including axially unless space is restricted.  Then try again with the JIS bit in a ring spanner.  If that fails, then the next attempt will be with a sharp small chisel radially on the edge of the head to try to spin it a tiny amount.
In your case, with one screw removed, have you tried striking the insulator on the alloy part anticlockwise to start the loosening process?  Only the O ring is stuck, there is just a metal to metal joint with no spigot.

Ian

[McCabe-Thiele (Ted)]

Mike,

In your case, with one screw removed, have you tried striking the insulator on the alloy part anticlockwise to start the loosening process?  Only the O ring is stuck, there is just a metal to metal joint with no spigot.

Ian

Well explained Ian, might be some good releasing fluid might help.

It's overcoming these ba***rd obstacles that rewards us in the end.

[Orcade-Ian]

Of course, some penetrating fluid and or heat (he's replacing them hopefully) and I forgot to mention another tool in my arsenal is a tiny Teng ratchet which takes 1/4 bits including JIS which are sometimes better than screwdrivers - it's only 3 1/2" long and be wedged sometimes with a block of wood to prevent the bit from 'camming out'.  In the decades that I've been struggling with these and similar recalcitrant little buggers, I've not been beaten yet!

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Ian

[Mikep328]

Thanks guys -good info!  I went out and fooled with it a bit and decided for now to leave things alone!  I was concerned that if something went badly wrong I could end up with a problem that required serious work to resolve.  So I put the one screw back in and re-fitted the carbs.  We have a ride planned for tomorrow and based on the way screw-removing was going, I didn't want to jeopardize that.  I think the new carb insulators will be a project for next year!