Honda305.com Forum

Best forum I've come across for the CB160.

My recently acquired 1968 CB160 seems in generally beautiful shape. BUT... the philips slots of the screw fastening the oil filter cap have been destroyed. Can't get any purchase on them with my impact driver.

A very delicate and ornery situation, as you all will understand.

A fool-proof method of extraction is probably asking too much... but I'd truly appreciate hearing input from those out there who have had experience with this disaster.

Thanks very much in advance.

Pfraser

Pfraser, can you dremel a flat grove through the bolt carefully and use your flat driver head with the impact with a little heat? I'd probably dip the head of the driver in some valve grinding paste to enhance the grip of the tool and help prevent slippage.

Failing that, I'd very carefully drill out the head of the screw and remove the plate. Apply heat and use vice grips or locking plyers.

Steve

Thanks for your reply, Steve.

The design of this oil filter rotor buries the cap retainer screw inside the rotor barrel, Access is through the hole in the cap that receives the exterior oil filter cover (which has the oil flow ports). Drilling the ruined screw head for an easy-out is possible. But I am very leery, and want to really consider all options. This is not a great place to go drilling metal... right in the guts of the engine, and no way to clean up any mess if the extraction effort is unsuccessful.

Can't file or grind off the screw head. And it is threaded into the crankshaft end, (I figure that must be so). If it broke off, I could then at least remove the cap and clean up. The cap could not be re-installed, though. And the only way to deal properly with the broken screw would be to tear everything down and remove the crank. Not a happy state of affairs, all around.

I have a picture in mind of a tool designed to fit over the head of a cap-head screw, sized to fit, and with sharp grabbers to sink into the screw head, so it could be turned out with an impact tool. I've never seen an extractor of this design, though. I was hoping someone on the forum would say they had seen them, used them, and they worked great.

Or some other clever way to get out of this without making a huge mess.

Any thoughts, anyone...

peter

Drill the head off the screw and remove oil filter end, what's left of the screw can be turned out with a vice grip or pliers. You may as well remove the side cover from the engine and clean the screen at the base of the oil pump too.

maybe a stripped screw extractor put into a 1/4 " socket on your impact screwdriver

Thanks for the input Mike and Russ. I will be seriously weighing all suggestions.

Fortunately there is no big hurry to get it done, so I have time to be very cautious.

It would be great to hear from someone who once had this exact same problem... and how they went about solving it and with what results...

Anyone out there..?

peter

I have done this in the past w/ good results.
Lay the bike onto its side and carefully hammer a chisel into the bungled phillips screw, you want to create a well defined slot for a straight bit to fit into.
Hammer the straight bit solidly into the screw and use your impact hammer to remove the screw.
I would not use a pneumatic impact tool, you want the hammer impact to drive that bit into the screw, also you want to twist the tool counter clockwise to transfer all the energy into the removal.