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??? - hardened (valve) seats, leaded and unleaded gas

Discussion in 'Norton Commando Motorcycles (Classic)' started by joe czech, Mar 19, 2019.

  1. joe czech

    joe czech

    Joined:
    Feb 21, 2019
    bare with me - another dumb noob question. I know pre-75, and pre-catalytic converter cars (at least in the U.S.) were designed to run on leaded gas, and after 1975, cars using unleaded gas had hardened exhaust valve seats. so, how does this apply to early bikes - in my case, a 74 850. assuming I can get this thing running, would I need to add an additive, or have the cylinder head reworked as I did with my 69 chevy? is this any kind of issue, or am I over thinking this, and having another brain-fart - :D

    another dumb question - any concern with ethanol based gas, and, I thought I read something about retarding the timing a bit to compensate for the lower octane in today's fuel. i'm thinking back in the day, we had around 100 octane leaded as the norm. basically today, I have two options - 93 octane ethanol, or 89 octane non-ethanol gas. TIA....
     
  2. kommando

    kommando

    Joined:
    May 7, 2005
    Your head came from the factory with hardened valve seats as standard, no additives required or for any other alloy head for Brit bikes either.

    I have not adjusted the timing for ethanol but better you have advice based on US fuels which are different.
     
  3. jbruney

    jbruney

    Joined:
    Jan 5, 2019
    My timing is the same now as it was then on this '74 850. I had the same concerns after starting up after letting it set since '80...No problems with premium unlead 10% or 90 ethanol free.
     
  4. lazyeye6

    lazyeye6 VIP MEMBER

    Joined:
    Feb 28, 2014
    My '74 850 runs just fine on 87 octane with 10% alcohol gas. I have a TriSpark ignition
    and time it to 28 degrees BTDC. I don't believe higher octane will do anything but cost
    more money. If I could readily get non-ethanol gas here in California I would do it in a heart beat.
    If you are interested in racing your need another opinion.
     
  5. L.A.B.

    L.A.B. Moderator VIP MEMBER

    Joined:
    Nov 20, 2004


    Most of the world uses the RON octane system, however, the USA and Canada use the AKI numbering system which is approximately 4-6 points lower than equivalent RON number.
    The numbers originally specified in handbooks, manuals, etc. would be for RON octane.

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

    "Difference between RON, MON, and AKI
    Because of the 8 to 12 octane number difference between RON and MON noted above, the AKI shown in Canada and the United States is 4 to 6 octane numbers lower than elsewhere in the world for the same fuel. This difference between RON and MON is known as the fuel's Sensitivity, and is not typically published for those countries that use the Anti-Knock Index labelling system."
     
  6. joe czech

    joe czech

    Joined:
    Feb 21, 2019
    man, do I feel stupid! aluminum head - hardened seats. duhhhhh!

    OK, so i'm looking at a copy of a 750 riders manual, and it states, to retard the timing a couple degrees if going from 100 octane to 96/97 and increase the main jet size from 220 to 250. i'm assuming the 850 riders manual would be the same. as L.A.B. stated, there is 4-6 octane points going from RON to AKI, so my current 93 would equate to approximately 98 (U.S. rating). going by the 750 owners manual, I should retard the timing by a couple degrees. however, several folks have stated they're running the factory spec'd timing without issues. anyway, nothing to worry about until I get it running.

    i'm looking into getting a couple AMAL premiums - anything i should note when ordering? i'm assuming 32mm would be standard replacements. comments. TIA....
     
  7. L.A.B.

    L.A.B. Moderator VIP MEMBER

    Joined:
    Nov 20, 2004
    The recommended RON octane for 850 models is 96 (or 94 if 96 is unavailable).
     
    joe czech likes this.
  8. joe czech

    joe czech

    Joined:
    Feb 21, 2019
    no racing - i'm 72 and those days are long gone. i'll be happy just to get the thing running. I've noted a lot of bikers here in florida running the 89 non-ethanol gas. we have one marathon station in bunnel florida with one pump. might try it for my first tank. only problem, they charge a premium - about a buck/gallon more. I run it in my emergency generator (w/ sta-bil) since it pretty much sits in stand-by mode. ethanol gas - not sure the good outweighs the bad. ;)
     
  9. Tornado

    Tornado VIP MEMBER

    Joined:
    Dec 5, 2017
    My 850 runs well on standard pump gas (87-94 AKI) here in Canada. I just run the standard timing as per workshop manual with EI (VapeWassell which uses same timing curve as the Boyer series II or IIII). Set it to 31 deg at 3000+ rpm.
    The main reason folks lean toward the higher octane rated gas seems to be b/c it also tends to be the ethanol free type....and that concern is more to do with ethanol fuel residue gumming up worries in the carb pilot jets....rather than timining/combustion issues.
     
  10. jbruney

    jbruney

    Joined:
    Jan 5, 2019
    You'll eventually get over the worry of the ethanol. Some Stabil, try to keep tank topped when it sits for a period, run top octane.
    Some folks at another site held my hand through the change. Europe, & have been having to do this and much more to ride theirs. We're definitely spoiled here....Avoid lead subs too...fouls plugs very fast(50mi.<)
     
  11. Lineslinger

    Lineslinger VIP MEMBER

    Joined:
    Feb 26, 2017
    Ethanol sucks.
     
    kommando likes this.
  12. Danno

    Danno

    Joined:
    Feb 7, 2010
    Keep your tank full as possible when you have ethanol-laced fuel. It sucks water out of the atmosphere which then lays on the bottom, either rusting the tank or getting sucked into the intakes.

    I just woke up a large Japanese 4-cylinder bike that sat outside all winter under a tarp and there was nearly a quart of water in the bottom of a 6-gallon tank.
     
  13. joe czech

    joe czech

    Joined:
    Feb 21, 2019
    I hear you - on the subject of tank rust, the previous owner stored my 850 with a half tank of gas (with sta-bil). the thing sat for 7 years - the sta-bil most likely was pretty much usless, but the half tank left the upper half of the tank with severe rust :( . another thing I need to address. need to do a search on the subject.
     
  14. jbruney

    jbruney

    Joined:
    Jan 5, 2019
    The electrolytic rust removal process works well for me. You only have to have one of the old battery chargers..new types don't work. My only source for ethanol free is 30mi. off & 90 oct.
     
  15. joe czech

    joe czech

    Joined:
    Feb 21, 2019
    my battery charger is 52 years old - 6/12 volt/6 amp, so I guess that will work! damn thing is probably older than a lot of folks here.
     
  16. Deets55

    Deets55 VIP MEMBER

    Joined:
    Oct 3, 2013

    Does it look like this?
    A8FBDA4A-C232-48A9-9FDC-96A911CC59D8.jpeg
     
  17. Chuck Weyant

    Chuck Weyant

    Joined:
    Dec 29, 2018
    Nothing good about alcohol in our fuel...nothing!
     
    MikeM likes this.
  18. jbruney

    jbruney

    Joined:
    Jan 5, 2019
    That is a beauty. I've seen one before, but lo was not able to beg my way into it.
    I wailed & fought the ethanol, and have now accepted that it isn't going away. My old Goldwing will burn it with little or no relish.....No 87 though. Makes it sound like an old tank.
     
  19. MikeM

    MikeM

    Joined:
    Jun 1, 2011
    Nice charger, but I think I will put it on the shelf to look at. Not plugging that one in!
     
  20. Deets55

    Deets55 VIP MEMBER

    Joined:
    Oct 3, 2013

    Man you guys are tough, 20 amps and tickle/fast charging. I had to give up my CTEK charger and cash for that Beauty.
    I got that over 25 years ago and it’s been sitting in the same spot until I took that picture.
     

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