I had a Honda 4 cylinder bike that had a ticking. It was not the exhaust, I suspected that first and replaced the copper exhaust gaskets. I also checked, before running it, if the right spark plugs were in there, on each cylinder. Eliminated those two problems right away.
An online forum suggest I check for a big-end connecting rod bearing issue. "How?" I asked.
They said if you can't identify which cylinder the ticking is from do the following for each cylinder. Use a vacuum or compressed air to clean the area of the cylinder head around the spark plug then remove it. Rotate the crank in the normal direction, and get the cylinder's piston to TDC (top dead center). Then rotate the crank some more, so the piston starts to drop in the cylinder -- let it drop a bit, to the point where you see the piston is falling, maybe 1/8 of the way down the bore for example. Then stop rotating the crank. Then put an object like, say, an unused wooden or plastic chop stick or a thin shaft like a long screwdriver down through the spark plug hole *carefully* and let it come to rest on top of the piston crown. Now *slowly* rotate the crankshaft *backward* and take note if you have to turn the crank backward more than you should before the piston starts going back up again. Because you have already had the piston dropping in its bore, when you reverse the crank direction, the piston start moving back upward pretty instantly, right? Use the motion of the chopstick to note any delay as you rotate the crank backward before the piston starts to rise in the cylinder. In other words, just as you start to rotate the crankshaft in the reverse direction, does the chopstick move right away? Or is there a delay? Do that for all 4 cylinders and compare. If you find a chopstick that does not move pretty instantly when you start rotating the crankshaft backward, that may mean you have a worn or bad rod bearing.
I had a bad big end bearing in the Honda and had to sell it for parts. It was that or pull the crank.
What happened is, as I found out from the upstanding citizen who sold me the bike, "it started making that ticking as I was revving the motor really high going down the freeway, and I had to pull over to see what it was." He over-revved it, which toasted a rod bearing.
I would imagine if you do have a bearing issue, it may not be severe enough (yet) for there to be enough slop using the chopstick method.
And of course it might be something else too.
