Tappety noise from engine

I thought it was pinking at first and checked the timing which shows 31BTDC (Boyer) The plugs BP7ES if anything I think are a bit 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 could I 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. So I've added a bit of video / sound from around the top and front of the engine.

http://s855.photobucket.com/albums/ab11 ... V02797.mp4

I would appreciate the more experienced fixers of these machines to have a listen and throw in their two peneth worth.

Cheers
Mac.

We would have to hear a video of it to help as its normal for a ring-a-ding-a-ling sound which is the head metal ringing as rockers tap valve stems and the cam chain spins. Its the loucdest noise at front of engine second to the exhaust blasts
smaching the header bend, which once wrapped goes away so even more oh no thoughts that are normal. On rides I swear its like two black smithers having at it like crazy but nothing comes apart.

On my earliest rides on 1st Combat I was so pensive of the ringing'clicking sounds i went at lugging speed home off hwy barely on throttle at jogging speed to sense if the sound was normal rythmic or erratic warning to suddenly here extra ring-dings so heart dropped till realized I was dive bombed by bats so close they chirp right at my face so was hearing part of their calls. Its happened 3 times on Peel, last time one even got tangled in the fork cable clutter so had to part them for its escape. Don't know if Commando make love calls or call outs to them. But attractive sound across species.

Here's a sense of the normal
[video]http://www.youtube.com/watch?v=L44j87_XsRU&feature=related[/video]

Single carb you say? This is just a guess but I have seen it before.

Pull you air cleaner off and as it pinks, touch the throttle slide with a screwdriver tip (as to not disturb air flow) to to steady it and keep it from slapping.

The theory is that the increased venturi velocity with one carb creates a fluctuation in pressure at the intake and osculates the slide against the bore.

Just a theory here and the more I listen to the vid the more I am inclined to sap this post. But what the hell.

We would have to hear a video of it to help as its normal for a ring-a-ding-a-ling sound which is the head metal ringing as rockers tap valve stems and the cam chain spins. Its the loucdest noise at front of engine second to the exhaust blasts

Hi Hobot.

Did the link to my video not work?
You can hear the noise on it quite clearly unless the noise that I'm hearing is a Commando norm!

pvisseriii said:

Single carb you say? This is just a guess but I have seen it before.

Pull you air cleaner off and as it pinks, touch the throttle slide with a screwdriver tip (as to not disturb air flow) to to steady it and keep it from slapping.

The theory is that the increased venturi velocity with one carb creates a fluctuation in pressure at the intake and osculates the slide against the bore.

Just a theory here.

Click to expand...

Amal is brand new with very little play in the bore, and the noise seems to be coming from the front of the engine, did the link to the video not work ?

This is why I wear a helmet...not so much to protect my head as to keep me from hearing my valve train! They are pretty noisy. Considering the video is shot from a position about where the coils sit, I think it sounds pretty normal.

Russ

This thread leads into something I have been thinking about for awhile. I regularly meet up with other Commando owners and in October there may be 15 or twenty at one gathering. I was thinking of setting up a camera in a set position. Put each of the bikes in the the staging area and start them and have them idle for a minute or two. Moving the microphone to different areas of the engine in a standard fashion and at the exhausts for each may give a pretty good audio display of several bikes.

Of course some will be 750's and 850's with different mods. The parameters of the bikes will be listed also.

The first time I got mine started was the first time I heard one live. I had no idea what I was hearing.

Is this something that might be helpful?

I often wonder if mine is making the right noises. I guess only time will tell, but I am gun shy after the first one ate itself.

Something isn't right for sure. I thought it sounded like a rattling rocker cover.

Are you sure you havnt been smokeing something , and hearing strange noises ? Just Kidding . A few stories there .

Id think a 250 is way down , maybe . And try 270 for starters . New Mk ONE Concentric ??

The 31 Degree is a optimum Ign. setting . The conservative 28 in ' a bit warm ' might be safer initially .

' The Big Chop Test ' isnt avoidable . A TEST ? . Niet . ' WE ' just whip the plugs and have a wee GLARE .

No need for Ton Downt Bypass and cut and declutch. ( at this stage ) . WERE JUST HAVEING A LOOK .

Not Melting , covered in oil , pocilane white , or bits missing . Tecnically , to much advance will erode the square edges of the centre electrode .

The Olde Bonnie would ping if prevoked , chunter stutter and act wild .And eroded them over time.However , a Commando is generally better behaved.
So Watch it.

OR THAT .

Needle centre clip & prepared for 1 up ( lift Needle ) . one or the other . WE should think .


Youre Timing Chains definately the right tension and not a cheap stretchy one ? Uneven stretch / wear gives uneven tension . So is not good .
Overtightenings not good either . Bit like seeing the ignitions right , There !

So , if we jet ' up ' for stsarters , have the odd ' plug inspection ' to see how its going , and hone to a knife edge from there ,if setting the world speed record. For trundling about and not trying to keep the front down out of the lights , its not neccesary to have optimum performance settings.

In fact youre tuneing it for drieability .

So THATS where your plug readings relate to .Where in the powerband / How your useing it .

A bit of forethough will assist in picking the transitions in the metering . Seldom possible to get ' dead right ' , So its got character , instead .
Not like a horrible C.V. thing . Though 1 3/4 SU's were used, & a Stromberg has a intregal float chamber.So for 2d there a o.k. score .



http://www.google.com.au/imgres?q=strom ... QCg&zoom=1

Hypothetical here , but should be easy to trip over in the U.K. but a early manual choke , not the notorious emmissionulated stringleised version.Except for parts .

Also get a long screwdriver , put it to your ear , and other end about the engine . lots of places .
But watch out for first ? above . A few have been stripped for no accountable reason .It just sounded loud.

your looking for comparitive sounds , or location off .

(1) Another thing to check is that the Alternator rotor isn't hitting the rivet pins holding the timing indicator in the outer primary cover.
This can happen in combination with excessive crankshaft end float & not using the big o ring to seal the primary halves, which holds the outer cover away from the rotor.

(2) Another one is possibly really worn camshaft bushes. Mine had 8.5 thou clearance when I got the bike, which we will say is just a bit excessive.

When I first got my bike it had all of the above happening at once with a similar if not louder version of the noise you have going on there.
I didn't isolate if it was one or the other as I totally dissassembled the bike & rebuilt it.

Hopefully it will be something simple as in No 1

Regards
Sweenz

when i first got my tr6r home and rode it, i turned around after a mile and came back home. Asked my father what he thought the noise was, his response: "youve just been spoiled with OHC; thats how everything old is. Get used to it." went through the same thing again when i got the norton.

hi, i had a bsa goldstar in a little while ago that was making a clattery sound, the owner said hed set the tappets. when i checked the left there was a gap o could nearly fit my head in, but the nut on the tappet was tight. needless to say he had set it randomly when the rocker was almost at the top of its stroke. not sayin youve done that, but maybe check them again, its the simplest thing

drones76 said:

This thread leads into something I have been thinking about for awhile. I regularly meet up with other Commando owners and in October there may be 15 or twenty at one gathering. I was thinking of setting up a camera in a set position. Put each of the bikes in the the staging area and start them and have them idle for a minute or two. Moving the microphone to different areas of the engine in a standard fashion and at the exhausts for each may give a pretty good audio display of several bikes.

Of course some will be 750's and 850's with different mods. The parameters of the bikes will be listed also.

The first time I got mine started was the first time I heard one live. I had no idea what I was hearing.

Is this something that might be helpful?

Click to expand...

I think something like that would be really usefull, but then again you might get one bike that's as rough as a bag of spanners and someone like me hearing that might think his is ok when in fact it's not. A carefull selection of fettled 850's and 750's would be the way to go.

flibity said:

hi, i had a bsa goldstar in a little while ago that was making a clattery sound, the owner said hed set the tappets. when i checked the left there was a gap o could nearly fit my head in, but the nut on the tappet was tight. needless to say he had set it randomly when the rocker was almost at the top of its stroke. not sayin youve done that, but maybe check them again, its the simplest thing

Click to expand...

I checked them first as that's what I thought it was clattering, and followed the method in the manual so it's not them.

Ugh Willie i'd skipped over URL to the photobucket video but heard it this am. It sounds distinctly louder ring/rattle than I'd be comfortable with just going by the microphone bias sensitivity so would hold more to your daddies seasoned ear with it running decent as it sounds response wise. Reading the list of things others listed above make my gut tighten and jaw slack with all the images they create when I'm heading out again after so so many show stoppers to meet good strangers or grit teeth leaving a neat lightweight bike in mid of no-where PU desperado land. It don't sound like its going to blow up but generally there ain't much warning anyway.

My pre-Peel Combat run like a bat out of hell and famous in surrounding counties for its performance over a couple decades before I accidently stumbled on it with owner in a mood for modern power cycle. I drag raced it the first week after half dozen crashes on THE Gravel travel. I didn't even know where the points were kept. I only took it apart to renew rings and fix 13 oil leak sites, but found bend crank and cracked cases [thankyou DynoDave with superman vision brain image processing] and fused fasteners and bent worn shafts like swing arm spindle that broke my bones and the swingarm to extract. It took me 5 yrs to source parts and machining and collect tool and data and dirty skills I never intended to want. It became like another mate to me and even gave me her name and is never out of my mind more than any lover, excepting my long missed P!! dragster. Then after wild adventures near and far for over a year, after a warm up run through our spring branch and muddy slow tire spin skewed climb out on tractor tire idled to shed to put on armor to ride away, I stepped on kicker that fired instantly to drop stiff leg bottom out that stumbled me backwards off bike she rev'd up on lightened flywheel to red zone before I could let go of throttle but throttle didn't let go so tach needle hit peg before I could reach forward to shut down then fuel puddle must of got sucked up and over size CHO ports hit their peak for such extra RPM rev up the engine roared back on the isolastics so hard it slapped my hand away so hard it shocked my nerves in reflex I again stumbled back in horror on invisible tach needle that took couple seconds to recover to grab throttle shut as tin shed sides and roof drummed and reasonated like whole orchester tune up dropped through the roof. Still working on that recover about 7 yrs now...

Then in interum got Trixie Combat before hurricane Katrina flooded shop. Trixie started right up after simple fluid change and new plugs and everything worked nicely so just started using her rather timidly - guilty I'd not gone through her soup to nuts, so 3 wks into just commute ride she seized up coasting at 50 mph. Found the taboo comma oil hole piston had let go because a taboo AL head gasket put in and it'd squashed down to intrude into bore and rub on pistons so even below red line running was fatiguing the Al stress rises. That took me most a year to recover, but reused the rod bolts with new nuts to have one let go 3 wk later on a timid commute and took 3 yr to recover.

So in many ways this is a real man's hobby horse to point being how lucky do ya feel punk to take chances or be totally responsible and go through soup to nuts for ride security and sense of self worth. I'd just ride it till something becomes obvious to fix and don't leave home w/o rescue plans made. This is totally logical in my world even going by my over sight lesions as in between the Trixie blow ups a deer in headlight and on helmet half destroyed Trixie half killed me to recover for nine mo. There is no logic but pure emotion to own motorcycles but oh what a ride till ya die eh.





T

Matt Spencer said:

Are you sure you havnt been smokeing something , and hearing strange noises ? Just Kidding . A few stories there .

Id think a 250 is way down , maybe . And try 270 for starters . New Mk ONE Concentric ??

The 31 Degree is a optimum Ign. setting . The conservative 28 in ' a bit warm ' might be safer initially .

' The Big Chop Test ' isnt avoidable . A TEST ? . Niet . ' WE ' just whip the plugs and have a wee GLARE .

No need for Ton Downt Bypass and cut and declutch. ( at this stage ) . WERE JUST HAVEING A LOOK .

Not Melting , covered in oil , pocilane white , or bits missing . Tecnically , to much advance will erode the square edges of the centre electrode .

The Olde Bonnie would ping if prevoked , chunter stutter and act wild .And eroded them over time.However , a Commando is generally better behaved.
So Watch it.


OR THAT .

Needle centre clip & prepared for 1 up ( lift Needle ) . one or the other . WE should think .


Youre Timing Chains definately the right tension and not a cheap stretchy one ? Uneven stretch / wear gives uneven tension . So is not good .
Overtightenings not good either . Bit like seeing the ignitions right , There !

So , if we jet ' up ' for stsarters , have the odd ' plug inspection ' to see how its going , and hone to a knife edge from there ,if setting the world speed record. For trundling about and not trying to keep the front down out of the lights , its not neccesary to have optimum performance settings.

In fact youre tuneing it for drieability .

So THATS where your plug readings relate to .Where in the powerband / How your useing it .

A bit of forethough will assist in picking the transitions in the metering . Seldom possible to get ' dead right ' , So its got character , instead .
Not like a horrible C.V. thing . Though 1 3/4 SU's were used, & a Stromberg has a intregal float chamber.So for 2d there a o.k. score .

http://www.google.com.au/imgres?q=strom ... QCg&zoom=1

Hypothetical here , but should be easy to trip over in the U.K. but a early manual choke , not the notorious emmissionulated stringleised version.Except for parts .

Click to expand...

Hi Matt Maybe smoking something strange would make everything sound just peachy? :shock:
But back in the real world it sounds like it does and the question is "Is it right"
I've dragged the timing back to around 29-30.
Plugs don't look too bad but running it at idle wont give a good indication of what it's doing further up the range so as it's a JPN I'll have to run it "With it's clothes off"! before I can pull them on the next run out. But I have raised the needle to the middle groove. I'll get a couple of different jets on order for the parts box.
Timing chain on this engine does not have a tensioner it's one of the early 750's with the canister up behind the barrels like the Atlas had. It was a job I meant to do when it was in bits but never got round to. The timing looks fairly steady with the strobe.
As it's just been rebuilt with a new bottom end it's in the running in stage so the highest it's been revved is 5000 while setting the timing, out on the road it's been nice and easy accels up to 4-5k max and no further as yet till I get a few miles on the clock.
I'll post some pictures of the plugs when I've had a run out.

Have you checked to make sure you have decent oil flow, the followers definitely get noisier when you starve them for oil.

If it is easy to do, you might want to post a video similar to the one Hobot posted. Start with the mic farther away from the bike and then move in close up as it makes it easier for somebody viewing to get a reference as to the microphone sensitivity.

Russ

Nice damage Steve ! Fixin' these boo-boos certainly keeps one out of trouble. A favorite movie of mine (now colorized) is Das Boot. The U-Boat engineer uses a metal tube to put his ear to the valve train to check on things and isolate future troubles before they start. Later on he has some real worrys to contend with.