I have developed a noise in what we have come to narrow down as the lower rear jug/lifter area.

I thought it may have been the lifter for we had the 2 push rods backwards on the cam/plate upgrade and and started it for a second, heard rod, shut it down and swapped out. Good to go. Not able to ride for almost 3 months.

Now I have been able to ride and began to hear noise in lower area. I began to question the primary chain at first. Checked, within specs. Then began to question the lifter for when we had it backwards, replaced both lifters and pushrods. No change at all. Checked compression, was with in 2 pounds of other cylinder, around 150-155lbs of compression, if I remember correctly.

We now have it narrowed down to what we feel is the rear lower jug/lifter area, with a mechanics stethoscope, and are out of ideas.
The initial reason we did the cam swap was the "Y" pipe broke on the rear jug and I had to limped it to work about 5 miles before able to shut it down and did not restart it till after the build of "Y" pipe, cams, plate, etc..

Any ideas?!?!?!?! It is a metalic click that is not anywhere in the front jug and in the 1200-1800rpm range and then the pipes drown it out. Seems to be harmonic. Don't really notice it at idle unless you are using a scope.

 

Well I would put your stethoscope right on the top of the rocker box and listen for noise. I had a valve guide seize to a valve that my ear said was a collapsed lifter. It caused the pushrod to chatter.

 

Done it. We put it everywhere that would allow us to while it was hot. Kept coming back to the rear area and more specifically the pushrod tubes and lifter area. Boxes were the same amount of noise.

 

The Y pipe on my bike cracked somewhere on the way back from Myrtle Beach last year. It wasn't loud enough for me to hear it over the exhaust and radio at 65 mph. The next morning I went to start the bike and it fired on the front cylinder only. I'd seized the rear exhaust valve.

A set on new / used heads and a 2 into 1 exhaust and the bike has been fine foor the past 21,000 miles. Perhaps you have a semi-sticky exhaust valve.

 

Thats an idea. I feel that the pipe was cracked for a minute before I knew it. We were maybe thinking maybe a cracked valve guide?!?!?!?