Just curious about fuel???? Any dire consequences using unleaded (ethonol added) fuel in the old Norton engines??? I was told "Probably not" by a reliable source. He told me if any problems did occur, it would be in the valve seats. Also, what octane runs best. I would assume super unleaded, but maybe not. Any comments?? Thanks. (pahtato/pahtayto)
Gasoline/Petrol (Tahmato/Tahmayto)
- Thread starter seadog57
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hi seadog,the only problem i can see, from reading previous posts,is if you are useing a fibre glass tank, you should,nt have problems with the valve seats
To my limited knowledge - these bikes don't need high octane. It doesn't do anything unless your engine is designed for for it. Higher octane doesn't mean extra explosive or more power - it's not like regular gas is watered down. I'm sure someone here can give you the proper explanation!
hope that helps!
Chris - it sounds like using a fiberglass tank will ensure that you won't have valve seat problems. I guess the gel coat gets deposited on the valves and protects the seats - kinda like the lead used to...
hope that helps!
Chris - it sounds like using a fiberglass tank will ensure that you won't have valve seat problems. I guess the gel coat gets deposited on the valves and protects the seats - kinda like the lead used to...
DogT
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You can read all about the fiberglass tanks and ethanol on this forum with a search. Most people use the sealers, I would not use f/g tank with ethanol unless it is sealed. Some have good luck, others not. Probably even better if you can find not-ethanol gas, but good luck, maybe at the airport, but it would be real high octane and expensive, but no worry about the f/g and the gel going into the carbs and gumming up the engine. I haven't decided myself.
Dave
69 'S' (f/g tank) Fireflake Blue
ps
The English invented the language but Americans improved it. (tamayto)
Dave
69 'S' (f/g tank) Fireflake Blue
ps
The English invented the language but Americans improved it. (tamayto)
I used the latest Caswell product on my recent glass tank find - we'll see how it holds up!
Phil
ps - Canadian English, definalty. We labour to put pop, not soda in the centre of our trunk, only our feet go in boots. We take the long route to the roof- not the short rauwt to the ruf, and I say Toemaydo, 'cause I live in Torono, not Tor-on-TOE. :mrgreen:
Phil
ps - Canadian English, definalty. We labour to put pop, not soda in the centre of our trunk, only our feet go in boots. We take the long route to the roof- not the short rauwt to the ruf, and I say Toemaydo, 'cause I live in Torono, not Tor-on-TOE. :mrgreen:
illf8ed said:
Isn't that what "super" means in Super Unleaded? Otherwise it's just unleaded.
Your Combat is a high(er) compression engine - it would benefit from higher octane as I understand it. Detonation is the effect of low octane in a high-compression engine. Or stated conversely - a high compression needs a higher combustion temp available in a more precisely calibrated fuel, with a higher Octane rating. That's the end of my scope of knowledge - gasoline gets complicated after that!! My limited knowledge comes from what I've read on the net and been told by my father who did his engineering thesis, waaay back in the 60's, on combustion design. Seems fitting for a Norton.
Wow! Thanks for all the feedback. Greatly appreciated! I remember when I was saving for a Commamdo and the price at the dealership was about $1900 U.S.(back in the previous century). Somehow I wound up with a 1972 XLCH Sportster (Boooo!) which, by the way, forever tainted my opinion of that marque!. Recalling back to that age of muscle cars and cheap high octane gasoline (petrol?), a machine wasn't a machine unless it required the likes of "Sunoco Blue". I believe 102 or 103 octane at the pump (If you remember the Sunoco gas station pumps had the dial on the side and you could select your octane rating! (purely an advertising gimmick). Back then, performance meant octane, and motorcycle manufacturers of high performance machines were no exception to the rule. The lead content TEA (Tetra Ethyl Lead) was done away with. This changed how engines were made (after the age on Norton????). By the way, regarding octane, the base for the octane rating at the pump of your local service station is stated on the pump itself. You may have noticed "octane method" R + M -:- 2. That stands for "Research + Motor -:- 2". The "Research" is the Lab "Spec" report of the gasoline octane content. The "Motor" is an actual motor they run the gas through that is able to calculate the octane content. They add the two octane findings together and -:- by 2 and that is the "at the pump" based octane rating. ( Sorry for rattling, I worked for many years as Captain on oil tankers with gasoline(petrol?) cargos).
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seadog57 said:
Just to avoid any confusion here, I would add that the "R + M -:- 2" system of rating pump fuel octane isn't generally used outside the USA & Canada.
In many countries of the world, the RON octane number is given at the pumps, and the octane rating recommendations given in the Commando riders manuals would be in RON octane, as far as I am aware.
http://www.torquecars.com/articles/fuel ... atings.php
http://www.btinternet.com/~madmole/Refe ... ONPON.html
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The question was are new valve seats required since leaded gas is not available. Hardened seats are to compensate for loss of the benefits of soft lead on earlier "soft" valve seats. Norton had already used valves seats hard enough to run with unleaded fuel. As you point out the purpose of higher octane rating is related to preventing engine detonation, a different subject and aspect of modern fuels. Unleaded - no problem. Low octane - a problem for high compression engines such as the combat. 
fastback said:
L.A.B. said:
Yes, the RON ( also MON) method is derived basically the same way as an average of the Research and Motor results. The scale used is the difference. Ron scale runs approximately 5 points higher then AKI (anti knock index) U.S.. I believe from the feedback here that I will go ahead and use "Super, Ultimate, Premium (whichever) and let the chips (hope that's not the chips of my valve seats) fall where they may.
http://www.torquecars.com/articles/fuel ... atings.php
http://www.btinternet.com/~madmole/Refe ... ONPON.html
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