Hello all,
Despite having been using this forum for several years now, this is my first topic post. I am incredibly thankful for all of you guys and the help and knowledge that you provide. I've had an issue with my '72 CB750 as of this past summer and I couldn't think of a better place to ask for assistance, so here I am.
First off, my bike is:
∙ 1972 CB750
∙ Stock carbs. with K&N pods (I know, "throw them away, use air box", I was able to dial in air/fuel well)
∙ 4 into 1 headers
∙ Dyna coils and dyna electronic ignition
Over last summer, I started experiencing a loud mechanical tick/knock along with a backfire, when at full operating temperature. I could tell for sure that it was coming from the valve train, so I decided to pull the engine and dive right in. What I found was that on the cylinder that I suspected the sound was coming from, the exhaust valve seat had come loose and rotated nearly 180 degress. So, my question is:
∙ How common is this?
∙ Who do you recommend in the U.S. to send my head out for new seats, for a guy who really doesn't have a lot of money?
Here's some pictures of what I found. You can see the machining mark is almost 180 degrees, indicated by my pick:
Thank you for your help. Again, I am incredibly appreciative for all the help you guys provide and have saved myself so much time just by logging into these forums.
