Is it about time to change the cam chain?

[scoot]

The engine started to sound pretty rackety about 200 miles ago. At around 3,000 rpms it would start to sound like a ball peen hammer hitting sheet metal like a machine gun on up to 4500 rpm, then fade away above 4500. I rode it like that back home about 100 miles. Tried to keep it out of that range as best I could. Noise came from the top of the engine, up front. And it only happens under load, rolling. Cannot get it to happen at full stop in neutral.

So back in the garage, I pulled the valve cover. Chain play over the guide is tight, can lift the chain maybe 1/4". Timing marks align well, on the camshafts and the timing plate. Valves are all within spec, they were re- shimmed around 1,000 miles ago. Compression readings 164,165,158,165. With a shot of oil the 158 went to 180psi. Removed the auto cct (Vision 550) and measured the max I could push the chain plate thing in as 1 3/4" using a socket extension. Then measured the original cct in my hand at its full extension as also 1 3/4". Then I re- installed the original cct, tightened it down and then removed it to measure it. Measures at 1/16" less than the max 1 3/4". Put that back in and went for a test ride. Same noise as before, if not more.

That's where I am tonight. Is the chain my issue? Will it maybe last another 1,500 miles? Bike's at 60,200 miles. I want to run halfway down the Baja peninsula next week to Bahia de Los Angeles for some riding, kayaking and fishing.

Should I put the auto cct back in? It has the potential to push past that 1 3/4" due to its being about a half inch longer than the original. Don't know if that's good or bad.

Thanks for listening.


scoot

[bikerphil]

I have 70K miles on a chain with an ACCT installed with no problems so far. Could your excessive top end noise be an exhaust leak at the header/cylinder head gasket(s)? JAT

[scoot]

No, Phil, gaskets are all tight. It's a metal sound for sure.

scoot

[motoman]

The engine started to sound pretty rackety about 200 miles ago. At around 3,000 rpms it would start to sound like a ball peen hammer hitting sheet metal like a machine gun on up to 4500 rpm, then fade away above 4500. I rode it like that back home about 100 miles. Tried to keep it out of that range as best I could. Noise came from the top of the engine, up front. And it only happens under load, rolling. Cannot get it to happen at full stop in neutral.

So back in the garage, I pulled the valve cover. Chain play over the guide is tight, can lift the chain maybe 1/4". Timing marks align well, on the camshafts and the timing plate. Valves are all within spec, they were re- shimmed around 1,000 miles ago. Compression readings 164,165,158,165. With a shot of oil the 158 went to 180psi. Removed the auto cct (Vision 550) and measured the max I could push the chain plate thing in as 1 3/4" using a socket extension. Then measured the original cct in my hand at its full extension as also 1 3/4". Then I re- installed the original cct, tightened it down and then removed it to measure it. Measures at 1/16" less than the max 1 3/4". Put that back in and went for a test ride. Same noise as before, if not more.

That's where I am tonight. Is the chain my issue? Will it maybe last another 1,500 miles? Bike's at 60,200 miles. I want to run halfway down the Baja peninsula next week to Bahia de Los Angeles for some riding, kayaking and fishing.

Should I put the auto cct back in? It has the potential to push past that 1 3/4" due to its being about a half inch longer than the original. Don't know if that's good or bad.

Thanks for listening.


scoot

Why would you have put the stock adjuster back in? If that's the case, then you can be sure the plunger slipped, causing the chain to hit case I've had them slip with a quick rev in nuetral. I'd put the auto adjuster back in. It's only gonna ratchet as far as needed to tighten chain. True, it has the potential to travel that far, but I would imagine if the chain pin connections got that worn, it would come apart before then.

[scoot]

I put the stock adjuster back in after measuring its length to see if that variable affected the loud top end noise as described above. I only rode a half mile to discover the problem is the same or worse, as it now clatters from lower rpms than before thru higher rpms, and now includes clatter on deceleration which was not obvious with the auto adjuster installed.

I don't mind reinstalling the auto adjuster, just looking for reassurance that it's not a bad idea at this point.

scoot

[jetmechmarty]

Check the tensioner assembly. It could have come apart. The plastic may have come off. I had slop like that in my chain, but no noise. I did replace the chain.

[mack]

Valve guides

When you re-did the valves, how did the oil seals and valve guides look? Did the sound come on all of a sudden or did it come on over a period of time , getting worse the more you rode it?

[scoot]

Check the tensioner assembly. It could have come apart. The plastic may have come off. I had slop like that in my chain, but no noise. I did replace the chain.

Excuse my ignorance- do you mean the plastic rectangular cap on the end of the stock tensioner? if so, it's fine. If you mean something inside the engine that the tensioner presses against, that part seems to be a thin metal plate perhaps in front of the chain itself? That will need further investigation. New ground for me.

scoot

[scoot]

When you re-did the valves, how did the oil seals and valve guides look? Did the sound come on all of a sudden or did it come on over a period of time , getting worse the more you rode it?

Hi Mack, I only changed the shims, did not pull the head or even the camshafts, just used that motionpro tool to get at the shims. And the sound did come on suddenly. I was riding into the desert just fine, then tatatatatatatat out of nowhere. this started within 15 minutes of starting the bike after a lunch stop. I had remembered that the bike started with a jolt when I cranked the starter, enough of a bang when it ignited, that I was surprised and thought, what the hell? Never did [I]that[I] before. And it's not done that again since. Only that one time. And then 15 minutes down the road, this top end racket started. Which is still here.

scoot

[jetmechmarty]

The chain rides on some sort of plastic surface. If that has departed, you'll get some noise. You will also have your CCT extended farther because of the missing surface. I'm not sure if you'll be able to see it with the valve cover off. Pull the oil filter and see if there are bits of plastic in it.

I am assuming the tensioner is made of metal with plastic bonded to it. I have not pulled or scrutinized one. Other bikes I am more familiar with are made as I describe.

[mack]

Unfortunately

I think you need to pull the valve cover off and have a look in there. Make sure the shims are all where they should be and the little bridge between the cc sprokets is in good shape.
Marty could be right, the tensioner/ cc guide has a rubber like surface contacting the chain. It could be damaged, but you won't get a good look at it unless you have a bore scope, or you pull the head. However, this would be something that should get worse over time not all of a sudden.
Either way, if it was one of my machines, that head would be off as soon as I got it home. And a very close inspection of all components would be underway right now.
If you do pull the head, look at your valve guide seals, if you see one damaged or distorted around the valve, you probably need work on that valve guide. It may be rattling around in there a bit. Also look at your buckets and check for galling. If its heavy, one or more of the oil gallaries may be blocked or restricted, however this too would get worse over time unless something got dropped in by accident and it just now plugged a hole.
Don't be afraid to pull the head and take it a part. Lots of horror stories on here about mistakes people have made, but if you follow the procedure in the manuals, you can have it off in an hour and apart in another hour.
These engines are noisy but the only metal on metal sound should come from the tapping at the shim surfaces.

[scoot]

[QUOTE=jetmechmarty;398032]

Pull the oil filter and see if there are bits of plastic in it.



Okay, I'm draining the cold oil now. Unfortunately, I lowered the bike from the lift to get at the oil drain plug, and in doing so, I had the bike settle onto the side stand before getting it up on the center stand. Which put the cam chain at risk of coming off the lower gear since the chain tensioner is removed. Poking the chain with my finger, it seems fine. How do I tell for sure that it didn't fall off?

[scoot]

I think you need to pull the valve cover off and have a look in there. Make sure the shims are all where they should be and the little bridge between the cc sprokets is in good shape.

I did this, and it all looks fine to me.

Don't be afraid to pull the head and take it a part. Lots of horror stories on here about mistakes people have made, but if you follow the procedure in the manuals, you can have it off in an hour and apart in another hour.

Can I reuse the head gasket?

[motoman]

I did this, and it all looks fine to me.



Can I reuse the head gasket?

Another thing to consider...........a bad diaphram in the vacuum advance can can hammer pretty loud! Make sure the vacuum advance hose is plugged on #2 carb, and not on intake boot. Unrestricted manifold vacuum(attached to incorrect port) will cause that diaphram to dance and hammer against outer can..... JAT, as I had a vacuum can diaphram go south and it hammered like pistons were switching holes.

[mack]

If you

were careful taking it off, you can reuse the valve cover gasket. Good idea to spray all your gaskets with PAM before you install. That way they come off intact and can be reused multiple times. Head gaskets not at all, unless it's pristine after removal but I've never seen one come off in good condition after any miles have been put on the motor.