Standard/non-standard engine noises

Having had a Norton, a 750 in a Matchless frame built 1966 and bought by me through several owners in 1969, I was familiar with the sound of the engine, that bike being my primary transportation for a couple of years. It's demise was rather spectacular. While on a long ride down I-65 from Hammond Indiana, it began running very rough. I turned around and headed back. I stopped and found the outer cover on the behind the cylinders mag had come loose and the cam ring was tilting! But with no tools I couldn't get the ring back in straight and that cover on tight enough. It was, I became sure, one cylinder was very advanced and the other was the opposite. Still it ran. And I trudged on with a worried mind, still trying to make it home. I got close. Three blocks from the house at a stop sign I reved it to start off an there was a loud (very loud!) Metal clunk and it stopped dead. I stood over the bike looking down at the bike and saw -- daylight and the road! where I should have seen the back of the cylinders. I'd blown the cylinders off the crankcase! Half the crankcase was ruined and half the the bottom of the cylinders was ruined. The only reason the cylinders were still there was because the pistons were still in the cylinders. Of course the rear wheel was locked solid. The old contraption had saved my life by going 'bang' at a stopsign rather than on I-65. Hind sight for a then very young and inexperienced guy: why didn't I just pull off the plug wire on the side with the over advance? My grievous fault. And I Never thought That would happen! Now, I thought the 'demise was kind of interesting never having heard of anything like this before or since. Probably because if it happenned to someone else they had both tools and the sense to fix the situation right off. Anyway, the demise isn't the real part of the question, but interesting I thought. Now I have a fairly low milage '74 850. It seems to be running fine except for random kickback when starting (the ignition system which I'm "rectifying"), but compared to my only other experience, this one sounds like a bucket of nuts and bolts being sloshed about. Not so bad that I hit the kill button, but I actually would like someone with good experience with Norton to listen to it and either say, " She's just fine," or "Sounds like your etc., etc. (Cam drive chain or whatever) is pretty worn. And I made sure my rocker to valve clearance is where it should be. Any experience in the Dayton/Cincinnati area?

I'll bet you can find a bike shop manager or mechanic somewhere in your area who has an ear for Nortons....you could also post a video in here with startup and rev/run sequence...there are enough educated ears in here to tell you whether or not there are engine issues.

My 650 Dommie has sounded like a bag of spanners for 42 years as I've posted before. Still running well ! Only 1400 miles this year, too cold now for my old bones to do any more. Ade.

Lineslinger said:

I'll bet you can find a bike shop manager or mechanic somewhere in your area who has an ear for Nortons....you could also post a video in here with startup and rev/run sequence...there are enough educated ears in here to tell you whether or not there are engine issues.

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Soon as I find out how to post a video with sound, I'll do it. Would want the sound quality to reflect realistically what it sounds like while I'm just standing there.

If it only sounds like a bag of spanners it is fine. Just as long as there's no screwdrivers or sockets in the bag.... Could be problematic then and taking a dive.... I know for sure mine is good because the noise comes from every place which has something spinning inside. Only two things which don't make noise are the tires.

my commando sounds like turbine compared to my 68 BSA A65 rattle-ing-est bike ever but buzzes down the road just fine

My take on Commando motors is; If it runs good, isn't spewing smoke & oil in undue abundance, and isn't tossing bits & pieces out of the cases that is in prime form. The noise & small leaks are proof the motor is running and has ample oil.

jbruney said:

My take on Commando motors is; If it runs good, isn't spewing smoke & oil in undue abundance, and isn't tossing bits & pieces out of the cases that is in prime form. The noise & small leaks are proof the motor is running and has ample oil.

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If that doesn't qualify it as a primative historic vehicle, I don't know what does. Went banging slowly away past a group of Harley guys outside some kind of meeting or club building and saw every head come up and slowly turn in unison.
"What the hell's that?"
"It's a big four stroke."
"Yeah, but what is it?"
I'm sure more than one of them knew. Anyway, does anyone know if we have any Norton club in my area -- southwest Ohio.

I was invited to have a brew by a local HD club member.... To shorten it up all his buds had to do a walk by looking, and again when I was leaving to see me crank it up… 1st kick left them speechless. Over half were not on deck when my bike was made and none believed the actual motor displacement because parallels look small to the untrained uneducated eye. I did explain that we had different concepts on acceleration.

Thanks for the email and the web site.

The key for me about any noise my Norton makes is consistency. If the noise is random and isn't related to a given RPM and/or gear then you may have an issue(s). I could, probably, say the same of my mistress...

If I switch helmets and/or the wind or temperature changes so do the noises I hear, so I have to "re-calibrate" my "sensors". Once I'm satisfied that all is good then I start the playlist on my IPod labeled "pin the throttle" (where I can)...

Best

RoadScholar said:

The key for me about any noise my Norton makes is consistency. If the noise is random and isn't related to a given RPM and/or gear then you may have an issue(s). I could, probably, say the same of my mistress...

If I switch helmets and/or the wind or temperature changes so do the noises I hear, so I have to "re-calibrate" my "sensors". Once I'm satisfied that all is good then I start the playlist on my IPod labeled "pin the throttle" (where I can)...

Best

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I'd think if she's leaving you (bike or mistress) the "noise" will become constant and loud, going up the scale when you try to "rev" her. Unhappy machinery.

Joe Schlaberdowski said:

I'd think if she's leaving you (bike or mistress) the "noise" will become constant and loud, going up the scale when you try to "rev" her. Unhappy machinery.

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A parting of the ways is inevitable; fortunately, associated noises usually wane. If you see acquiring/meeting as the beginning of a new and exciting adventure then you must accept selling-on/moving-on in the same light for it means that an equally exciting adventure(s) is about to begin...

Best

Well..... You don't come home early and find the neighbor mounting your bike either.... I've heard only a few Commandos running in my time and all were noisier than a zoo at feeding time.

Things like a rhythmic rapping on the primary side upon decelleration or low rpm blips of the throttle is often a primary chain slapping the primary case as it goes slack. With my bike, the faster I go, the better it sounds up until the engine is screaming. At that point it still sounds "good" but I know I am putting the most stress on every part of the engine, so if it's going to break that's probably when it will happen. Since it doesn't break and it sounds good at high rpm, I don't sweat the inherent low speed valve tapping and chain slapping sounds that occur at low rpms...

jbruney said:

Well..... You don't come home early and find the neighbor mounting your bike either.... I've heard only a few Commandos running in my time and all were noisier than a zoo at feeding time.

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I was going to try and reply to that, but I gave up.

Joe Schlaberdowski said:

Soon as I find out how to post a video with sound, I'll do it. Would want the sound quality to reflect realistically what it sounds like while I'm just standing there.

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To post a video all you need do is record what you want, upload it to YouTube or other hosting site like Vimeo etc. , then paste a link to that video in a reply text box. There is no ability to upload a video directly this site as far as I'm aware.

jbruney said:

Well..... You don't come home early and find the neighbor mounting your bike either.... I've heard only a few Commandos running in my time and all were noisier than a zoo at feeding time.

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This reminds me of an old adage .... three things you never lend out: your motorcycle, chainsaw, or your wife/girl friend. If you ever get any one back, you can be sure it has had a rod thrown in it.

Slick

That's okay Joe. I think I was implying that the Norton is truly yours and yours only..... I forget... age coming on. I'll go kiss my Commando goodnight and kick the old lady over a few times.