Engine noise - Does this sound OK?

Stuart SS said:

Last I looked regular is down to 88 octane and Premium 91 octane.

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:shock: :shock:

Murray If I put 88 in my Commando or worse still the Trident ~ it would definitely sound like hell and High water has descended upon the bike ~

In fact I put a questionable amount of fuel into the Trident at a back water fuel stop on a club ride ~ and despite adding fuel booster when I struggled home~ the bike was NOT a happy camper and I had to drain it out and add a fresh load of 95 before it was again happy !

Here in Oz we chose can between <92 - 98> An extended road test by a very well qualified member of our bike group has put it down to <95-96 > being the most appropriate rated fuel for our classics ~

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The USA (and Canada where I believe Murray B is?) use the AKI/PON octane rating system (R+M)/2) so US/Can. fuel octane numbers are somewhat lower than the equivalent RON octane numbers commonly used in many other countries.

http://en.wikipedia.org/wiki/Octane_rating

L.A.B. said:

The USA (and Canada where I believe Murray B is?) use the AKI/PON octane rating system (R+M)/2) so US/Can. fuel octane numbers are somewhat lower than the equivalent RON octane numbers commonly used in many other countries.

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L.A.B. That's very interesting. So what is the generally accepted best performing US octane rating for stock nortons? If they found the best in Aus was 95-96 in then maybe 90-91 US might be better here in the US.

biffom said:

L.A.B. said:

The USA (and Canada where I believe Murray B is?) use the AKI/PON octane rating system (R+M)/2) so US/Can. fuel octane numbers are somewhat lower than the equivalent RON octane numbers commonly used in many other countries.

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So what is the generally accepted best performing US octane rating for stock nortons? If they found the best in Aus was 95-96 in then maybe 90-91 US might be better here in the US.

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Try to use the highest available pump octane whenever possible.

The early Commando owners handbooks state: "Not less than 99 octane". The 220000 handbook says: "fuel of not less than 99 octane" or as an alternative, 96 octane could be used for 8.9:1 comp. ratio 750 models with jetting and ignition timing changes if 99 octane was unavailable, and 100 octane or alternatively 97 octane for 9.5:1 comp/ratio models (alt. 94 octane + jet & ign. changes), and 96 octane (alt. 94 + jet change only) for 850 models (8.75:1 comp./ratio). For 850 Mk3 the handbook says: "this motorcycle is designed to operate on fuels of at least 94 octane..." All quoted handbook octane ratings will be RON.

Just to be clear here, the 1973 850 Riders manual P16 says "This motorcycle is designed to operate on fuels of at least 94 octane rating (UK 3-Star or USA Regular).

Haven't been following closely here, what is the history of this engine ?

A sticky valve can sound very clattery - can either be through gunged up oil, or brand new guides with too tight a clearance.

Rohan said:

Just to be clear here, the 1973 850 Riders manual P16 says "This motorcycle is designed to operate on fuels of at least 94 octane rating (UK 3-Star or USA Regular).

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Is that the later 850 "Noise Control" model Riders' Handbook? As it doesn't say that in the original 1973 750 & 850 copy. The UK "3-star" octane rating is no longer applicable and "US Regular" appears to be only 87 PON/AKI (91-92 RON) now.

http://en.wikipedia.org/wiki/Octane_rating

"regular" gasoline in Australia, New Zealand, Canada and the US 87

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Says for Commando 850 motorcycles including special noise control models copyright 1973.
Part number 065321. Pic is of an 850 Interstate, with ham can perforated aircleaner.

Rohan said:

Says for Commando 850 motorcycles including special noise control models copyright 1973.
Part number 065321. Pic is of an 850 Interstate, with ham can perforated aircleaner.

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That is the later handbook for 1974 850 and includes the noise control 'A' models, I don't have a copy of that particular handbook, it obviously contains the same fuel information as the 850 Mk3 handbook (that also contains the reference to UK "3-star" and US "Regular" info which I omitted to avoid possible confusion).

Mine runs real good on BP 110LL avgas.

Dave
69S

Back in the seventies the Canadian government legislated the lead out of gasoline. They said it was harmless to vehicles and was better for the environment. Virtually all media sources agreed but not my old uncle the Dodge mechanic. He warned me that if I used unleaded in my Commando it would take out the valves in short order. Being a young smartass pup I figured my uncle was some sort of luddite and put in unleaded anyway. Within about 2000 miles my valve guides went and had to be replaced. It was lucky the bike was still under warranty and the dealer repaired them at no cost to me. They put in new valves rated for unleaded fuel and I never had the problem again but I did learn to listen to my uncle.

Fast forward to now. Governments are legislating ethanol into our fuel. They say it is harmless to vehicles and is better for the environment. Sadly, my uncle is long dead so I can’t ask him, but Amal warns:

“The addition of ethanol to petrol has an effect on both the performance of an engine and also its interaction with the different materials it comes into contact with...lowers mpg and raises NOx in vehicles without a three way catalyst... The addition of ethanol causes fuel to absorb water... It becomes acidic and conductive causing both a chemical reaction with certain materials and galvanic reaction causing corrosion...As water is heavier than petrol...layering effect...fuel having a higher water content settling to the bottom... Ethanol readily permeates through elastomers and plastics resulting in a deterioration of these materials... The company is already effecting changes... Needles will be produced in nickel silver whilst orifices will be made from manganese bronze. Diaphragms and O rings to be upgraded to Viton or other suitable material. Rubber petrol pipe to be internally lined or upgraded.”

The long version is posted at http://www.amalcarb.co.uk/TechnicalDetail.aspx?id=10

I also understand that the adulterated fuel burns “funny” and can cause some engines to make odd noises.

I don’t know about anybody else but I am such a chicken that I am going Ethanol free for as long as possible.

P.S. Maybe it isn't the fuel but I really hope it is just that and not something more serious.

Murray B said:

Fast forward to now. Governments are legislating ethanol into our fuel.

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Yes, well, the addition of ethanol to pump fuel has been causing problems for several years. Previous forum discussions on this subject date back to at least 2004.

The 50 wt. made a huge difference. Sounds all better. The stethoscope on the carb will hear the intake valve seating and rocker coming back down on top the valve so no cause for concern.

As others have mentioned video recorded audio differs greatly from what people hear because our brains filter and purify sound selectively. Microphones don't, so when we play back electrically recorded sounds it sounds quite different. I'm not an audio engineer but I've worked in video production for 20 years and as such own and use about $10,000.00 in audio field recording equipment so I have some experience here. As Hobot pointed out, take a wrench and strike it against a fin on the head or cylinder and listen to the sound that resonates. Unlike modern bikes Nortons are made of real metal, thick and solid and they sing.

Sound of a Norton fin being struck with a wrench:

T i n g - T i n g

Sound of an import bike:

Dung Dung

DogT said:

Mine runs real good on BP 110LL avgas.

Dave
69S

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No problems here with unleaded 93 octanne w/ 10% ethanol to boot! Must be that Mikuni TM34 flat slide I'm running....OK, where's the get-out-of-way "duck" emoticon I've seen on other Forums?????

Murray B said:

Back in the seventies the Canadian government legislated the lead out of gasoline. They said it was harmless to vehicles and was better for the environment. Virtually all media sources agreed but not my old uncle the Dodge mechanic. He warned me that if I used unleaded in my Commando it would take out the valves in short order. Being a young smartass pup I figured my uncle was some sort of luddite and put in unleaded anyway. Within about 2000 miles my valve guides went and had to be replaced. It was lucky the bike was still under warranty and the dealer repaired them at no cost to me. They put in new valves rated for unleaded fuel and I never had the problem again but I did learn to listen to my uncle.

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In 1977, Irving became the first Canadian oil company to offer unleaded gasoline at its retail outlets

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So, how do you get warranty years and years after the bike was new ??
You spinning us a yarn here....

As stated era was early 70's Norton was still paying warranty so the one telling the yarn was your uncle as nothing needs to be done to make Commandos No Lead tolerate. The issue was in other engine brands valve seats not valve guides anyway.

[video]http://www.youtube.com/watch?v=MLIaqwS0kmM[/video]

RennieK said:

The 50 wt. made a huge difference. Sounds all better. The stethoscope on the carb will hear the intake valve seating and rocker coming back down on top the valve so no cause for concern.

As others have mentioned video recorded audio differs greatly from what people hear because our brains filter and purify sound selectively. Microphones don't, so when we play back electrically recorded sounds it sounds quite different. I'm not an audio engineer but I've worked in video production for 20 years and as such own and use about $10,000.00 in audio field recording equipment so I have some experience here. As Hobot pointed out, take a wrench and strike it against a fin on the head or cylinder and listen to the sound that resonates. Unlike modern bikes Nortons are made of real metal, thick and solid and they sing.

Sound of a Norton fin being struck with a wrench:

T i n g - T i n g

Sound of an import bike:

Dung Dung

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Thanks for that. I've successfully managed to cut out some of the Ting Ting Ting.

A nice gentleman followed me home on a Harley. He'd had three Nortons (used to drag race them up in Michigan - many a tale). I managed to corner him (wasn't hard) into listening to the engine noise. He didn't seem to think it was now much of an issue. But I have to say there was almost zero engine noise from his Harley - plenty of exhaust.

Re: the recording gear - I was trying to clean up the sound using an iphone (way cheaper buying an app here than a pro app on the desktop) and stumbled across a ton of spectrum analyzer apps but nothing that would selectively filter out various frequencies. It was a shame because for this kind of application it would be really cool to lose the base of the exhaust and focus in on sounds that matter.

Hey biffom, It's usually the other way around,.... drown out the engine noise so we can here the exhaust.
As with most of the threads here when someone is showing off their pride and joy, usually all you can here is engine rattle.
Glad to hear she's OK.
AC.

Wrap the headers and/or use a stethoscope to hear mechanical sounds of valve train ringingdinging the head. With a tiny gas tank on at speed and/or putting on a big wind screen with lowers you can really hear the turmoil going on over the exhaust bark at speed. If you do you may not like what ya hear, a high speed metal processor chopping device.

ludwig said:

grandpaul said:

..Best thing would be for someone who has been around Commandos for a while to visit you ..

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GP is allready on his way ..

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- never fails to get me chuckling Ludwig -


http://www.lotustalk.com/forums/attachm ... hg_clr.gif

L.A.B. said:

Yes, well, the addition of ethanol to pump fuel has been causing problems for several years. Previous forum discussions on this subject date back to at least 2004.

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Yes but Amal mentions "galvanic" which is electrochemistry that can probably take out some types of stainless steel. Look at the materials they are using in their 2012 carbs. If what they are writing is true then it seems that ethanol is worse then I ever thought it was.