Spark plug threads?

[guest]

Mike, is there a way to clean up spark plug threads with out removing the heads. My threads are not cross threaded and do not appear damaged but over time I notice that my plugs do not go in as easy as they use to. I can no longer just thread them in with my fingers until the washer is touching and need to use the spark plug wrench. this all started when I used a set of champion plugs instead of stock HD plugs. I know the Champion were supposed to be the same but the threads seemed just a little courser. I always use anti sieze too. thanks guest.

[Mike]

Probably picked up a piece of carbon on the tip end threads. You can get a thread chaser at an auto parts store to clean up the threads. Put grease on the the threads of the chaser to help capture the few chips you should generate by chasing. Do this with the piston at bottom dead center, then when done, rotate the motor to blow out any remaining bits (if the piston is anywhere else it will momemtarily suck in debris). Of course the correct way is to pull the head (just to be PC). Just like carbon bits, the motor can digest very small pieces of this material without harm (contrary to popular belief).
Regards, Mike

[guest]

Mike, thanks for the reply. What size chaser do I need? I stopped the Snap-on truck and he said that Snap-On used to make a tool for Harley threads but stopped making it and that he could not get them any more. he said to use a tap, but I don't want something that cuts new threads do I. I was under the impression that a thread chaser just cleaned up the old threads not actually cut them. Thanks again for your help and time.

[Mike]

I would try Baxter auto parts. For Twin Cams you'll need a 12mm and for EV's a 14.
Thanks, Mike