Bonneville America Forums Forums Technical Forums General Tech Tick, tick, tick

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".

Difficult to imagine that an eccentric aluminum journal would wear the cam to this extent. At the very least, I would expect the journal to be nearly destroyed by the time there was significant shaping of the hardened steel of the cam. It's only an educated guess of course, but I'll bet the cam was slightly OOR from the gitgo. A runout of .11mm is huge. You no doubt were losing the oil film between the cam and journal long ago. The wear was probably accelerating rapidly over the last few hundred miles.

Regarding the head in the other bike, you might want to take a good look since running the bad cam to see if there's any scuffing on the journal surface. Aluminum is probably as good as any other bearing material, but an oblong cam will chew it up in a hurry.

Sorry you're having these problems.

Jack

wow i would have missed that to. good to know that is something to look for.

Frank

Since I first got my 05 BA, It had that little Harley trait, little drop of oil. Mine was on the cyl. fins, just below the head.
It was under warranty, so I let the dealer deal with it.
He kept thinking it was a bad seal at the Breather tube to head.
Well, it was. But it wasn't due to a bad O-ring, it was a bad head casting, where the surface machining had a bad imperfection due to missing material from the casting.
Thank God it was under warranty, as my dealer said the head and related parts was almost $1,500.00, and the labor bill was almost $1,000.00.
Sounds like Triumph needs to improve their heads, or maybe our two problems are rare?

Will you come be my mechanic?

Thank you for sharing your knowledge and congratulations on the fix.

I appreciated the detail you put into that post. Glad you shared everything with us.

Do you still have the old head and cam bearing caps? I'm sure a good machine shop would have been able to aluminum weld the cam bearing bore and ream it out to the proper size. Did you notice if the oil gallery was plugged to the cam bearing journal?

Bummer about having to buy a new head, chy. I have a one in perfect shape with all the fixins right in the classifieds. Glad you got it all worked out.

I gotta concur with the problem being the cam, rather than the journal. As you pointed out aluminium aint ever going to wear hardened steel - far more likely the cam's dodgy from the factory and has worn out the journal.

I'd be inclined to have someone weld & grind the cam into round, then find an appropriate sized bearing, grind the journal and slip the bearing in. You might even want to do ALL the journals while you're at it - that way it'll never happen again. Cam wears out? Oversized bearings (yay for old fashioned engineering).

Wendys has gotten loud now too, I hope it is just out of adjustment as it's time to do the job. Mine is loud too but I never thought of the cam or head being worn. Sounds normal to me but now I'm going to have to go look at both bikes. I have said for the day I found out they didn't have cam bearing that I wish they did and thought it was a bad idea not to for just such a reason or future rebuilding.

My bike as developed a tick lately. I checked the valves and I had one out of adjustment. All the others were well within tolerance. After adjusting the valve it got a little better but it's still there. When I had the intake cam off the bike I noticed a slight scoring on the right rear camshaft bearing. I'm not sure but some foreign matter must have made it's way into the bearing through the little oil port at the top. I'm wondering if I should replace that collar or just ride the way it is. I know those collars are matched up at the factory. The bike is running fine but I still hear a slight tick.

You can't replace the bearing caps they are specific to each journal and head because of the way they are bored.

It seemed to me that they all tick a bit.Is it true to most of our bikes or not? Mine has done it since new and the other bike I originally test road did it also. I just figure it is part of the breed.Kawasaki Vulcans hydraulic lifters like to tap in there bikes also I have heard and read.

Yeah, let's not go overboard here... these bikes WILL tick - it's a by-product of the overhead cam system that Triumph uses and is fairly peculiar to British engines (you should hear the top end of an original mini engine at full noise). Normal ticking sounds a bit like a sewing machine - lots of little mechanical bits working away furiously and will be louder when cold (bigger valve gaps due to metal not yet expanding). The ticking that you'll get from a sloppy cam journal will sound more like a bad big end bearing (higher pitched though), will be a lot fewer ticks per revolution than normal top end noise (1 loud tick per revolution as the cam rotates, rather than the normal 8 little ticks per revolution as the valves operate), and will get louder with heat (due to hot oil falling away from the overly large bearing gap).

The odds of an out of round cam journal are very small (though obviously there IS a chance of it), and the odds of a pack of them occurring and not being detected for six years are minuscule.