Engine making "clackity clack" noises

[four winds]

The same for my '67 TR6c flattracker. Mainly as a result of after market valve springs that held more pressure than stock.

Clearance wears tight on new and rebuilt engines as the valves seat.

Clearance wears loose in the long run from wear on cam lobes, lifters and rocker ends as A64pilot points out. Add to those rocker shaft bushings or bearings and valve stems.

So one surface wears tight (mostly initially) and many other surfaces wear loose (much more common in my experience).

[four winds]

Yeah, the old thudy thudy.

Part way closed? That would be the same as saying sticking open slightly?. In that case a solid lift cam would have extra clearance, not no clearance. Because the valve stem did not return to the position at which the proper clearance was set.

Every engine, car or bike is a piece of junk to someone.

On edit..... Guy, it appears you may have been referring to carbon build-up on the valve stem tip. If so that would decrease clearance. Though I've never seen deposits there since that surface gets hammered by the rocker arm dozens of times per second at higher rpm.

Originally Posted by Guy

Anybody remember the Duntov 30 30 cam?

Carbon build up on a very worn valve stem can cause the valve to stick part way closed. With solid lifters, you would then have no gap and no noise. Side play in the valve guide will cause smoke for sure but it's not the kind of thing that makes a noise. From the few older Perkins type engines I've looked at, I don't think they suffer from the same kind of problems that a piece of junk English motorcycle or lightweight airplane engine suffer from. I might fly over an ocean in a Lycoming or Continental powered airplane but no one would ever put one in a boat.

[reed1v]

Originally Posted by darylat8750

The issue is that other parts of the valve train besides the valves and valve seats wear also.

1. My '66 Triumph opened up so bad that I had to adjust valves after every race. Always needed to be closed a little. It was the cam followers that wore so bad that they needed to be replaced every season. (It wasn't the surface on the cam that wore, but the interface between the lifter and the push rods.)

2. '70 Corvette with after market cam and solid lifters intake valves would usually get looser (but not always) and the exhaust valves usually got tighter.

These examples had very aggressive cam profiles but I had several '80s street bikes that could "go either way".

You had a triumph bonneville?

[model 10]

Originally Posted by four winds

Y
On edit..... Guy, it appears you may have been referring to carbon build-up on the valve stem tip. If so that would decrease clearance. Though I've never seen deposits there since that surface gets hammered by the rocker arm dozens of times per second at higher rpm.

Never heard of carbon build up on a valve tip, how could that happen?
The piston side of the valve guide is the first to wear. That along with oil leakage allows a lump of carbon to build on the valve stem where there is the extra clearance from wear in the valve guide. At some point that lump of carbon gets big enough to hold the valve off the seat. If you had a lump of carbon build to the point it held the valve from closing, you would have no valve clearance at all. The lifter would always be in contact with the cam and the valve tip would always be in contact with the rocker. There is nothing to make noise. Here is where you guys are right, If the valve sticks say half way in it's travel then you get a clack big time as the valve train has probably a 1/2" of slop.
I thought this was a 1500 hour engine we were talking about?

[four winds]

Seen plenty of carbon build-up on valves, every mechanic has.

What is a valve tip?

The only location where build-up could reduce clearance is at the interface between the valve stem and the rocker arm. That is where the rocker touches the valve stem. And is what I call the valve stem tip. Have never seen build-up there.

Build-up anywhere else on a valve, for whatever reason, that causes a valve to not fully close will increase clearance.

Most cams have less than a half inch lift. Rocker ratios commonly around 1.5 to 1. So a rocker moves one quarter inch to push a valve a half inch.

Even if a valve stuck full open, the slack would be half that at the rocker.

Thought the drift was concerning valve trains in general. The OP issue is resolved.

I've commented enough on this drift. So I'll be on my way.

Cheers.

[darylat8750]

Originally Posted by reed1v

You had a triumph bonneville?

Yep, '66 T120R

[Cadence]

Going back to the OP. When he took the cover off? Engine room hatch or valve cover?
He may be chasing a phantom, all valves click a bit maybe not hearable buttoned up. I would rather have a click than a burnt valve.

[Paul54]

Originally Posted by darylat8750

Yep, '66 T120R

I had a 67 Tiger, a 68 Bonneville, and a Trident. Love those bikes.

[Cadence]

Originally Posted by Paul54

I had a 67 Tiger, a 68 Bonneville, and a Trident. Love those bikes.

Damn, you have to be like me, older than dirt. English scooters were the thing in the day.

[four winds]

Thread drift to English bikes.... 67 tr6c track bike converted to streetracker after racing, and a 73 Trident that was unrestored original for me.

Let's post pictures .... Yeah thread drift. I got pics......

[Cadence]

Originally Posted by four winds

Thread drift to English bikes.... 67 tr6c track bike converted to streetracker after racing, and a 73 Trident that was unrestored original for me.

Let's post pictures .... Yeah thread drift. I got pics......

What was the OP? I guess there must be a bike thread someplace?

[belizesailor]

Originally Posted by a64pilot

You guys did notice OP said he changed oil and the noise went away?

Ha, thats clearly no longer imporant!

[model 10]

Oh man, I had a Triumph Tiger Cub when I was a kid then I had a BSA 650 twin carb and my last bike was a 79 Triumph 750 twin.

[a64pilot]

You guy's are older than dirt, my first street bike was a 78 KZ-650, last one was a CBR-1100XX.
Just realized, I don't have a street bike anymore, well back where i started I guess?


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[bsams]

63 TR6 Trophy was my first bike. Still in my dad's garage.

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