As some of you know, I have been chasing a very annoying ticking noise in my engine for quite some time. So I thought I'd share the symptoms and ultimately the fix in case it happens to any of you.
It started out innocently enough.. a barely audible ticking that would fade in and then back out, usually at a stop or just as the RPM's drop as I'm rolling to a stop. It eventually got to the point where it was pretty much constant... a slight tick on the left (#1) cylinder.
Although not time for a valve adjustment, I went ahead and put everything back to specs.. dead in the middle.. every one. .279 for the exhaust and .178 for the intake (don't ask me.. I didn't build the feeler gauges). There was nothing way out of whack but I figured I was just focusing on it making it seem louder.. yeah right. Started her up and tick, tick, tick... now I'm getting concerned.
Having checked everything and knowing all was working correctly, I decided to try to ignore it and get on with the business of riding. After all the bike ran great and I had no further symptoms. Of course I was hearing the thing all the time as I was now focusing on the that particular sound and it started slowly driving me mad.
Eventually it got louder and louder, till my tick, tick, tick was now a
TICK,TICK,TICK and the sound was actually reverberating through the cooling fins on the head. My handy dandy stethoscope revealed the noise to be more prominent at the l/side header to the head connection. With that I replaced the exhaust seals on the header pipe.. nothing.. didn't change a thing.
I worried and fretted with this thing for months and even went so far as to talk to the tech guys at Triumph but it was as big a mystery to them as it was to me.
I finally decided that this problem was going to just get worse and I really needed to get to the bottom of this issue and pulled the cylinder head off the engine. I check the valve springs, valves, combustion chamber, shim buckets, cylinder wall and piston wrist pin.. nothing.. nadda. Now I'm getting frustrated...
Feeling in my gut that there was a problem with the head itself that I simply couldn't find, I started reassembling the cylinder head with the ultimate goal of putting it back together and riding it till it flies apart.. then I could find the problem.
While doing a bench valve adjustment, I was double checking my gaps again.. when I noticed the exhaust camshaft actually moved up in the saddle when I slid in a thicker feeler gauge. Everything was properly torqued and this shouldn't be happening.. whaddupwiddis? You could watch the thing moving up and down in the saddle.. ahh hah! there is the culprit.
As you probably know, there are no cam bearings in our engines so this meant the replacement of the cylinder head.. at 35,000 miles.. we are not amused since that sucker costs somewhere in the neighborhood of 1100.00. Triumph corporate didn't seem to sympathetic as the bike was like 6 years old so no help was offered but a call to our friend Peter Carleo ( dang good guy)at Triumph got me a good deal on the head.. he sold it to me a Triumph cost.. still not great but muuuch better.
So here I go with my new head.. reseat the valves, readjust everything and here we go... reassemble the engine, fire it up and... tick, tick, tick... not nearly as loud but still there. At this point I'm baffled..frustrated and confused, I consider myself to be a dang good mechanic and this thing is just making a fool of me.
I rode the bike for another few hundred miles racking my brain on what the problem might be. Turns out what I knew.. or thought I knew was working against me. When I found the problem with the head, I considered the camshaft might be worn as well but blew it off thinking that the camshaft is case hardened steel and the head is aluminum.. the saddle on the head being the weakest point.. la la la... but it stuck in my mind just the same.
Frustrated with the whole dang thing I finally got both my Americas (yes, I have two) out yesterday morning and set into changing out the exhaust cams. I checked the suspected camshaft with my micrometer and found a .11 mm run out on the suspect surface..( egg shaped) checking the camshaft from the one that didn't tick is a mere .02 mm.
I then went ahead with the camshaft swap, adjusted the valves and for the first time in over a year, I hear my engine run minus the tick, tick, tick. Now just to confirm my findings, and hoping it wasn't a fluke, I installed my old camshaft into the other head, adjust the valves and have successfully moved the tick!
No doubt the old head was bad as the bearing saddle had far too much clearance but now I have to ask... was the camshaft the source of the problem or was it head itself? Too much clearance between the mating surfaces would have let the cam walk up and down in the saddle and eventually oblong the hole.. but if the camshaft were out of round from the get go, it would have had the same effect. So .. what came first.. the chicken or the egg?
Sorry for the length of this little story but it has been long in the making. I just thought I would share it in hopes that it may help someone with similar issues.
The moral of the story? Check everything! don't assume anything! I should have followed my gut and checked the camshaft when I replaced the head.. but I didn't... and it cost me a lot of time and aggravation.
The last remaining question being... did the time I ran the bad camshaft in the new head lead to the ultimate failure of this one as well?.. I s'pose only time will tell but as of right now.. I'm riding "tickless".
