Carb-to-head manifold "insulator" removal - SUCCESS!

[mattsz]

Sorry if this is a lame question...

My carb manifold rubbers have hardened up dramatically - I've decided to remove them and either try some softening alchemy or buy new - but I can't loosen the screws.  I'm nervous about stripping out the heads, so I've been cautious to avoid using too much force on ill-fitting "phillips" screwdrivers, the best fitting option I've found so far is the Honda tool kit large cross-head bit and the cross bar that fits it for leverage (see photo), but that applies a slow steady torque, no way to "shock" the screw loose with that tool.

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Penetrating oil doesn't seem to penetrate.  I tried heat on one of them; no joy but I don't know how effective I was - I used a heat gun and the head really absorbed and dispersed the heat from it.  I could try that for a longer time.  I didn't use a propane torch, as I'm worried I'll damage the rubber.  Even if I had one, I don't think I could fit an impact driver in there and still swing a hammer (the engine is in the frame).

Any tricks to this, other than the usual generic suggestions?

[robvangulik]

Find a longer bit for your impact driver....and buy some JIS screwdrivers.

[Bryanj]

Make sure they are JIS impact driver bits

[mattsz]

Find a longer bit for your impact driver....and buy some JIS screwdrivers.

Rob - as I said, I don't have an impact driver.  If I did, how would a longer bit help?

There's only about 6 inches between the screws and the frame.  How do you place an impact driver and strike it in that space?

[robvangulik]

Sorry, I misread that a bit, BUT an impact driver is, in my opinion, a tool you need to have. And you don't know before you try if it would work in this case and space. I think it will....

[mattsz]

Sorry, I misread that a bit, BUT an impact driver is, in my opinion, a tool you need to have. And you don't know before you try if it would work in this case and space. I think it will....

Are you talking about one of these?

[robvangulik]

Yes, I even have 2 

[mattsz]

Yes, I even have 2 

I assume you need to hold it perpendicular to the fastener, then hit it with a hammer.  How much space do you require to use it?

[robvangulik]

You always can better hit softly with a big hammer than hard with a small one
If there is indeed too little space to swing a hammer in your frame, you can use it as a (very sturdy) normal screwdriver and use more force than a normal one. And like I wrote, get some JIS screwdrivers, an impact driver isn't expensive, a good JIS (Vessel for instance) a bit more, but you'll never forget the day you started using those tools, in a positive way

[Winterfield]

I take it the engine is still in the frame? I couldn't get my impact driver (like the one pictured above) to get them out, there was no space to swing a hammer.

What I ended up doing was to repeatedly use penetrating oil on the screws over a period of days. Then I used the bit from my impact driver, which was quite a large diameter, along with an 8mm socket in a wrench. The bit went into the socket, and I used the leverage from the wrench while pushing hard down on the wrench head to stop the bit from jumping out of the screw. Much to my surprise, the screws came out without damage.

I think the trick is to find the perfect fitting driver, more likely than not, JIS as mentioned above.

[Bryanj]

Always tap the bit into the screw head before trying to turn, it jars the thread

[mattsz]

Thanks, everyone!  Penetrating oil over two days hasn't seemed to help - I assumed that the rubber was sealing it out.

I do have a couple of bits that, while they aren't indicated as JIS per se, they do fit snugly into the Honda screws without any play.  I've used one in particular to loosen a few screws that were already damaged by ill-fitting tools.  I have a t-bar that could work - maybe I'll use it to apply the rotational force and get my wife to tap it with a hammer - she's been looking for ways to participate in my motorcycle hobby...

[mattsz]

Thanks again, gang!  I got them all - using the T-bar and tight-fitting bit.  Really just a heavier-duty (much!) version of the tool from my first post.

I was able to drive the bit into each screw and have it stick tightly, after which careful use of the T-bar broke them all free with a loud snap.  I worried each time that I had broken something, but no.  Two of the heads have been mangled already though (even so, the hammered bit worked), so I'm going to replace them.  Might use some allen socket screws...

[Athame57]

I quickly gave up trying to take mine out as I started damaging the screwhead. I've opted to wait until I finally get my leaky head gasket changed and have it done then.

[Oggers]

Penetrating fluid?