74 CB360G R-crankcase screw's problem

[roadrunner]

Hi all,i just purchasced this bike from Iowa original owner in a action,it has 3900 mi's on it.i am doing the service routine and started to unscrew the R-crankcase to clean out oil cup and the screw head broke off so i got the easyout & it broke off in the screw!now what do i do the other screws are just as tight bike has been sitting scene 1980 & the screws have never been touched.does anybody know how i can get these screws out.i have tried drilling it and so fare no go.need help please Mike

[Hahnda]

If I can't get them out with an hammer hit impact driver and a good fitting bit I usually use a 1/8" drill bit and drill in until I think I am below the head. Then I use a 1/4" bit and drill until the head pops off. Once the cover is off you can usually unscrew what is left of the screw quite easily.

[G3]

Years ago when I encountered the same problem, a fellow forum member warned me of the misuse of the impact driver and the consequences, and boy was he right!
His instruction to me for difficult screws was to use the proper bit from an interchangeable driver and with a peening hammer, whack the head of the screw a couple of times and then try to remove the stubborn screw using the impact. Some added to the conversation by suggesting a penetrating oil of your choice sprayed on and then the next day whack the thing as previously described. I used the latter method and it worked for me. Something to do with the "dead blow" of the impact without the twisting action broke the bond if you can call it that.

[roadrunner]

Thank's Guy's all of that info. well go to work ASAP.i was also told by someone that the Honda Factory coat the steel screws with zinc as the zinc drops off the steel screw mash's with the aluminum case.??? thxs Guys Mike