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Tappety noise from engine

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I thought it was pinking at first and checked the timing which shows 31BTDC (Boyer) The plugs BP7ES if anythingI thinkare abit weak but not given it the chop test yet, I'm running a single new Amal with a 250 main, and 106 needle jet, No 3 slide with the needle on the bottom groove.

Valve clearances are good and were checked at the same time as the rest of the checks

I thought pinking just happened under load but I can hear this with the engine running under no load, it might be nothing except a "Commando Noise" that I've not got used to yet but what else couldI look at?

Bike starts and runs fine but this noise is on my mind all the time, any Idea's? I know it's difficult to arrive at a diagnosis without hearing it yourself but it might just throw up some idea's of what it might be.

Once I've done a plug chop I'll post some pictures of the plugs.

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Hi Mac,

As you say,diagnosingnoises is always tricky.

What has changed ? Have you just got the bike or had it awhileand the noise started ?

Are you able to compare to another Commando ?

Does it make the noise at tickover / cold / hot.

If it makes no difference on load / off load then it would suggest it is not pinking / small ends.

Can you hear it when riding ?

If so have you tried earplugs ? (Just joking).

Regards

Tony

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If the noise is not at full engine speed then I'd suspect perhaps either a loose push rod end or maybe the cam follower tunnels are worn. The followers can make quite a lot of noisy clacking low down at the front of the cylinders if they are a rattling fit.

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If you are running regular unleaded you may need to retard the ignition a few degrees - perhaps to 27 degrees BTDC. It depends on your compression ratio of course. But runnning weak would exacerbate a tendancy to pink. Pinking would only occur under load though.

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Hi Mac

Just a thought but you could try recording the noise (smart phone?) and adding the sound file to your post?

Good luck

Peter

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Previously wrote:

Hi Mac,

As you say,diagnosingnoises is always tricky.

What has changed ? Have you just got the bike or had it awhileand the noise started ?

Are you able to compare to another Commando ?

Does it make the noise at tickover / cold / hot.

If it makes no difference on load / off load then it would suggest it is not pinking / small ends.

Can you hear it when riding ?

If so have you tried earplugs ? (Just joking).

Regards

Tony

Hi Tony

I've had the bike for a long time but it's just been rebuilt after the return oil line blew out of the block on the crankcase with disasterous results. I just put it on the road on Aug 1st and I'm still just taking short runs out on it till I feel all is good.

The crank has been rebuilt and balanced with con rods that a friend of mine got hold of, you mention the small ends I'm pretty sure they were a good fit on the gudgeon pinbut how much wear would cause clacking.

I can hear it when riding, the bike isJPN replica so all the noise from the engine just gets amplified by the fairing,there are a few suggestions on hereabout recording the noise, I might just do that with a video if I can figure out how to add one.

Thanks for your suggestions I'll have a wee play with the bike and see if I can answer some more questions.

Cheers

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Previously wrote:

If the noise is not at full engine speed then I'd suspect perhaps either a loose push rod end or maybe the cam follower tunnels are worn. The followers can make quite a lot of noisy clacking low down at the front of the cylinders if they are a rattling fit.

Hi Richard

Clacking describes the sound pretty well, I'm going to attempt to put a soundtrack on here to see if that helps any, worn follower tunnels mean new barrels does it not?

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http://s855.photobucket.com/albums/ab118/mac_macdonald/?action=view&current=MOV02797.mp4

I've made a short bit of video here around the top and front of the engine I think you can hear the clacking pretty clearly, now the question is "Is that a normal Commando noise" or am I being a bit paranoid after rebuilding the engine?

Your well tuned Commando ears will hopefully be better able to tellthan me.

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New cam followers are supplied slightly oversize and generally need lapping into the barrel (at least that's what I do). I believe also that several dealers offer sleeving of the tunnels so you're not into scrap barrel territory.

I've known Commandos with what sounded like a death rattle from the followers and they can go on for years and years without getting worse. It's not pleasant to listen to though.

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Previously wrote:

New cam followers are supplied slightly oversize and generally need lapping into the barrel (at least that's what I do). I believe also that several dealers offer sleeving of the tunnels so you're not into scrap barrel territory.

I've known Commandos with what sounded like a death rattle from the followers and they can go on for years and years without getting worse. It's not pleasant to listen to though.

http://s855.photobucket.com/albums/ab118/mac_macdonald/?action=view&current=MOV02797.mp4

Hi Again Richard

Does this sound like cam followers?

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That's an odd one, isn't it ? It doesn't seem to be precisely linked to rpm. It sounds so metallic and undamped that I'd almost suspect something outside of the engine like a loose exhaust flange or a headsteady making metal to metal contact. It doesn't sound like the followers to me. Being camshaft related, they usually seem to have a half-time frequency. This noise sounds like it's at crank rpm at tickover but then doesn't rise in line.

Sorry that this is more thinking aloud than positive help.

If I didn't find anything external then I think that I'd want to take the top end off for a look.

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Hi Mac

I had a similar sound experience. It turned out to be a broken cam follower. Valve clearence didn't change. Remove magnetic plug and sump filter and check for "Shrapnel".

Regards Leif

Attachments Camfollower.JPG
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Previously wrote:

Hi Mac

I had a similar sound experience. It turned out to be a broken cam follower. Valve clearence didn't change. Remove magnetic plug and sump filter and check for "Shrapnel".

Regards Leif

Hi Leif

Been there already, with no sign of any metal paricles, what was the cam lobe like after that?

Mac.

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Previously wrote:

If my bike was making that noise after a rebuild, I would take the head off and look for witness marks...

Hi Gordon

Where would you look for witness marks? In the head itself, Valves, Rockers, the bike has been running fine surely if something was making contact with something else it would have gone by now, especially revving it to 5000 to set up the timing?

I take it from hearing the video you don't think it's just a Commando noise then?

Mac.

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MAC

I had a similar noise, this may sound daft , but try running her with the side stand down, my problem was amissing rubber buffer from the side stand, causing the stand to touch against the nearside exhaust

good luck

steve elston

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Previously wrote:

Previously wrote:

Hi Mac

I had a similar sound experience. It turned out to be a broken cam follower. Valve clearence didn't change. Remove magnetic plug and sump filter and check for "Shrapnel".

Regards Leif

Hi Leif

Been there already, with no sign of any metal paricles, what was the cam lobe like after that?

Mac.

Hi Mac

Not good, but I was tired of it anyway (3S, bad idle, leaking at point seal). Replaced it with a PW3, idle is now steady at 900-1000rpm, no leaks :)

I would keep looking for the source of the noise, it sounds to loud to ignore.

Good luck.

Leif

Attachments Cam.JPG
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No, not just a Commando noise. My Commando never sounded like that even when the hardened foot came off a cam follower. I would check every aspect of the valve gear, including valves touching the piston crowns. If there is absoluteley nothing there, check small ends and big ends for play. I suspect that it is something in the valve train, but what... It doesn't sound like an external noise - too regular for that. With something resonating externally, I would expect it to disappear or buzz as you hit resonant frequencies. This noise is precisely matched to engine rpm. Off with its head I fear.

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The "clacking" sound diminishes as the engine speed increases. What happens under load? Is it it worse at low revs as you pull away from a standstill? Does it get less when the engine is hot?

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Last time I heard a Norton engine sounding like that was my friends Atlas when the skirt fell off the piston! Hope yours turns out to be something different but it does sound like you need to investigate further to get to the root of it. A good tip for locating/narrowing down where exactly the noise is coming from is to get a length of garden hose, about 2 feet or so long, put one end to your ear & with the other end, go round the engine using it like a stethoscope, you should at least be able to get a good idea whether it's top end, middle or bottom, on the afore mentioned Atlas, the noise was loudest if the pipe was pushed in the rear barrel to head nut recess in the barrel, you could almost feel the clacking coming up the pipe.

HTH,

Regards, Tim

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They're not quiet engines and it doesn't sound too bad to me, not as if a pistons fallen apart FFS. Listen to this, a Norman White re-build just started and running for a minute. Presumably with used barrels, new tappets and PW3. Mine sounds like this and it's not falling apart, also has PW3 and new tappets 5000 miles ago + new barrels 26,000 miles ago. Yes I have heard Commandos ticking over so quietly I wouldn't have recognised them as such.

http://s424.photobucket.com/albums/pp322/keith1069/?action=view&current=PRshort2.mp4

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Previously wrote:

They're not quiet engines and it doesn't sound too bad to me, not as if a pistons fallen apart FFS. Listen to this, a Norman White re-build just started and running for a minute. Presumably with used barrels, new tappets and PW3. Mine sounds like this and it's not falling apart, also has PW3 and new tappets 5000 miles ago + new barrels 26,000 miles ago. Yes I have heard Commandos ticking over so quietly I wouldn't have recognised them as such.

http://s424.photobucket.com/albums/pp322/keith1069/?action=view&current=PRshort2.mp4

That sounds worse than mine!!!!

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Just taken the bike out for a quick blast with the tank shroud off to make getting at the plugs easier, the noise is definately louder when pulling away but then seems to clear as the revs clear 2500-3000 is this a significant range? Don't seem to hear it above that but then the exhausts take over plus the wind noise!Ran out for approx 5 miles at a steady 4000 and chopped the engine pulled the plugs and I think I might be a wee tadge weak, opinions please.http://i855.photobucket.com/albums/ab11 ... C02805.jpghttp://i855.photobucket.com/albums/ab11 ... C02806.jpgwilly mac
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Plugs look OK to me. Typical of appearance running with with modern petrol.

Hard to tell but I think your clacking sounds like a slack little end.

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Thanks for all your input people, unfortunately I need to go back to work to get some pennies, so any further investigation will need to wait on my return in a few weeks time.

A member of another Norton forum has suggested theThackary washers may be the cause, they're just called spring washers in the parts catalogue, apparently they have been known to wear the side of the rocker arm then catch and twang.

He does refer to the NOC as being the source of this info, but I've not heard anyone mention it yet!

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I take it from the lack of replies that the "Thackery washers on the rocker spindles"suggestion causing the clacking is a dead end then?

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They can lose their springyness and stop pushing all the bits together so creating extra noise, they can be replaced with correctly dimensioned spacers as they to on racers to reduce the drag they cause.

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Finally the website allows me to post...

Was there any work done on the bore and pistons? Allthough the noise on mine was not as sharp as on yours, it was particularly there at low revs and take off if I remember correctly,,proved to be too much piston clearance.

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Previously wrote:

Finally the website allows me to post...

Was there any work done on the bore and pistons? Allthough the noise on mine was not as sharp as on yours, it was particularly there at low revs and take off if I remember correctly,,proved to be too much piston clearance.

No work was done on the bores or pistons, all seemed good in that area with no excessive slopping about. Surely if the wear was that bad I'd have other issues? Or would I?

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Previously wrote:

They can lose their springyness and stop pushing all the bits together so creating extra noise, they can be replaced with correctly dimensioned spacers as they to on racers to reduce the drag they cause.

Hi John, so it's not an uncommon problem then!

I've seen the spacers are available from RGM but is the measuring up to get the spacers correct possible with the head still on the bike, or is it a "Off with it's head job"?

Mac.

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Previously wrote:

Finally the website allows me to post...

Was there any work done on the bore and pistons? Allthough the noise on mine was not as sharp as on yours, it was particularly there at low revs and take off if I remember correctly,,proved to be too much piston clearance.

The noise is more prominent at take off however, how much piston clearance are we talking about here? I would imagine it would have been slopping about in the bore?

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I think it was 0.3 mm max.

When installing new oversize pistons on a 850, I ask the machinist to provide0.11 mm clearance (0.0043 in.). Have had no seizures with that. I don't race it.

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Previously wrote:

Previously wrote: Are the push rods are engaged in the rocker cups?

If any of the rods were not in place would I not have a strange clearance at the adjuster?

I suppose any of them being misaligned could cause a bit of a "Tappety noise" is this something you've seen or done yourself before?

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Previously wrote:

You would be going nowhere very fast if the push rod ends are not engaged!

I thought that might be the case, it's been up to 5000 to set the timing and it's also run fine out on the road.

I've bought a proper stethoscope to go round the whole top end with so when I get back home I should be able to do a bit more investigation into the "Clatter"

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Previously wrote:

Previously wrote:

You would be going nowhere very fast if the push rod ends are not engaged!

I thought that might be the case, it's been up to 5000 to set the timing and it's also run fine out on the road.

I've bought a proper stethoscope to go round the whole top end with so when I get back home I should be able to do a bit more investigation into the "Clatter"

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It is a pretty scary noise and sounds like metal to metal to me. I would remove the head and barrel and see what transpires. The camshaft may be striking the bottom of the barrels if you've changed the cam or purposely left out the base gasket. Probably not what you want to hear but I would be reluctant to travel any distance on it.

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Previously wrote:

Check your camshaft nut in the timing case is nice and tight.

Not sure how the nut being loose would cause the clatter!

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Previously wrote:

It is a pretty scary noise and sounds like metal to metal to me. I would remove the head and barrel and see what transpires. The camshaft may be striking the bottom of the barrels if you've changed the cam or purposely left out the base gasket. Probably not what you want to hear but I would be reluctant to travel any distance on it.

If the cam was touching the Barrels then there would be evidence of this in the sump, as for not fitting a base gasket ! well that wouldend up with oil all over the place I've got none of these symptoms.

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hello if the bike running weak then you can lift the needle up one notch to make it richer . tapping noise could be the rock shafts in the head thats loose or worn alloy in the head , but not the shaft it self .or the piston catching the cylinder head inside there needs too be some clearance there , try fitting a thicker base gasket , all try out these new Bosch muilty electrode spark plugs log on to www.greensparkplug.co.uk and read the bit about mulity electrodes spark plugs , I am using them in my 650 twin and it starts first kick and runs very nice and its, wait for it, Quiet running ! Yours Anna J

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Previously wrote:

Previously wrote:

Check your camshaft nut in the timing case is nice and tight.

Not sure how the nut being loose would cause the clatter!

Mac

My domi was making the same sort of noise as the sound yours is making

I completely stripped the head and barrels and found no evidence of any wear or anything out of place.

I replaced the barrels and head but with only one push rod at a time and found that the noise only occured when the nearside exhaust and offside inlet push rods where in place.

Looking in the timing chest I noticed that the camshaft nut had moved on the tab washer. The tab was flattened and the loose nut tightened and loctited.

I reassembled the enginge and the noise has completely disappeared.

I can only assume the the cam had moved into such a position thatadjacent cam followers were striking the wrong lobes on the cam during their cycle.

Worth having a look on yours just to make sure

Mike

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Previously wrote:

Previously wrote:

Previously wrote:

Check your camshaft nut in the timing case is nice and tight.

Not sure how the nut being loose would cause the clatter!

Mac

My domi was making the same sort of noise as the sound yours is making

I completely stripped the head and barrels and found no evidence of any wear or anything out of place.

I replaced the barrels and head but with only one push rod at a time and found that the noise only occured when the nearside exhaust and offside inlet push rods where in place.

Looking in the timing chest I noticed that the camshaft nut had moved on the tab washer. The tab was flattened and the loose nut tightened and loctited.

I reassembled the enginge and the noise has completely disappeared.

I can only assume the the cam had moved into such a position thatadjacent cam followers were striking the wrong lobes on the cam during their cycle.

Worth having a look on yours just to make sure

Mike

Hi Mike

I'm trying to figure out how the cam can move sideways enough to catch the adjacent follower when it's in the crankcases,the end float would have to be pretty bad for that to happen, and the nut is only there to holdthe drive sprocket onto the cami think during your reassembly you corrected the fault without knowing what it actually caused it. I'll be having a good probe about with the stethescope so hopefully should be able to localise where it's coming from, watch this space.

Permalink

Previously wrote:

Previously wrote:

Previously wrote:

Previously wrote:

Check your camshaft nut in the timing case is nice and tight.

Not sure how the nut being loose would cause the clatter!

Mac

My domi was making the same sort of noise as the sound yours is making

I completely stripped the head and barrels and found no evidence of any wear or anything out of place.

I replaced the barrels and head but with only one push rod at a time and found that the noise only occured when the nearside exhaust and offside inlet push rods where in place.

Looking in the timing chest I noticed that the camshaft nut had moved on the tab washer. The tab was flattened and the loose nut tightened and loctited.

I reassembled the enginge and the noise has completely disappeared.

I can only assume the the cam had moved into such a position thatadjacent cam followers were striking the wrong lobes on the cam during their cycle.

Worth having a look on yours just to make sure

Mike

Hi Mike

I'm trying to figure out how the cam can move sideways enough to catch the adjacent follower when it's in the crankcases,the end float would have to be pretty bad for that to happen, and the nut is only there to holdthe drive sprocket onto the cami think during your reassembly you corrected the fault without knowing what it actually caused it. I'll be having a good probe about with the stethescope so hopefully should be able to localise where it's coming from, watch this space.

Hi Mac

I must admit to being with you on this but tightening the nut was the last action performed.

On turning the engine overslowly using the kick start the cam would jerk round at every 180 degrees causing the cam chain to chase the sproket momentarily (if that makes sense). I can only assume that something (cam follower?) was striking a cam lobe causing this action and making the clatter noise. This didn't happen when the head was removed so suspected something in the valve train.

As you say maybe something else happened during reassembly. We'll never know.

Good luck with yours. It will be interesting to hear what transpires

Mike

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Been to the SCMC meet tonight and had a Norton owner of many years have a listen to the clatter. Engine running 1st gear wheel against the wall let clutch out easy and it clatters like a good un, small ends seems to be the opinion. When the engine was built the conrods were second hand but appearedto be within service limits, obviously not! Looking at a couple of spares suppliers (Norvil and RGM) it doesn't seem like you can get small end bearings as replacements does anyone know any better or even better have a part no?

 

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