Motorcycle Repair: 1964 Honda CT200, screw head, thread pitch


Question
Motorcycle Repair: 1964 Honda CT200, screw head, thread pitch
CT200/CA200 clutch
I am restoring this cycle and need to remove the clutch. In looking at parts diagrams it appears someone put a CA200 clutch on this cycle. There are two screws on the face of the housing, are these what's holding it on? They don't want to break free with an impact driver, are they left hand thread? Do you know of anywhere I could find a service manual to purchase or someone that has one I could get copies of certain subjects.

Bottom line how do I remove the clutch. Photos are available

Answer
David, well it does look like a C/CA200 clutch with the two screws holding the outer plate in place. It is possible that the two screws have been in place for 46 years and they do get bonded into place.

Whenever you start loosening screws in the 1960s models, I suggest that you use the impact driver bit as a shock tool, by inserting the correct tip (looks like a #2, in this case) into the screw head and whack it with a big brass or steel hammer a couple of times. That direct impact to the screw head and threads usually loosens the corrosion bond enough to allow the impact driver tool to turn them out afterwards. If you bugger up the screw heads too much then you can just drill the heads off the screws and replace them with new ones, except you will have to rethread them to the newer ISO thread pitch. Early 5mm screws were JIS thread and they had a different thread pitch. You can also try a crescent wrench on the #2 bit, after you have hit the screw head a few times, to help turn it out. If you have a small center punch with sharp tip, you can sometimes catch the edges of the screw head and rotate the screw out with accurate hammer tool tip placement.   

http://www.cmsnl.com/honda-ca200-honda-90-us_model999/partslist/E++05.html for clutch exploded views and other illustrations on that site.

Once you get the outer plate off, then you may or may not need the 4 prong nut tool to get the nut off the end of the crankshaft. If accessible, you can sometimes use a thin chisel or punch to catch the edges of the nut to spin it off.

There are NO LEFT HAND threads on these engines.

Bill Silver