Opinions on that Airhead higher 5th gear?

Discussion in 'Airheads' started by elmontanero, Aug 7, 2010.

  1. Stagehand

    Stagehand Imperfectionist

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    techincally, carrying a thicker head gasket would get you a lower CR, but you dont want to be swapping that around for a tank of fuel :D

    Easier to retard the timing if there was a problem, I think.

    Like you say though, it really depends on where you think youre headed. I've never had to buy gas out from a hand pump in a barrel, or a soft-drink bottle, yet, but they are out there, deep in Mexico and Cambodia. I would think fuel contaminants would be a way more frequent thing, like water or just crap, and not the octane rating. Hell, its almost impossible to find Leaded fuel anymore, and I've never heard of anything below say, 85 or so.
  2. ontic

    ontic

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    Thicker head gasket is one option I had read of and could be a solution, but yeah, this certainly wouldn't be done for a tank of fuel- more like done for a ride through a region of expected poor fuel- if the fuel was proving a problem.
    Timing retarding might be a better way. Nice if it could be done at the press of a button...

    I've done a fair bit of riding in Vietnam and Laos and a little in Cambodia and Thailand. Aside from the major cities in Laos, when off the main tracks where I tend to gravitate to, most of the fuel I bought was out of soft drink bottles and a fair bit of it in vietnam was the same, and if it wasn't that then it was hand pumped out of a barrel. Actual bowsers were very uncommon where I rode. Didn't seem like bad fuel as such, but on rented bikes I really didn't pay much attention nor care so long as it ran.

    I'll definitely be doing a lot of riding through those regions, not to mention Timor, Indonesia and Malaysia in order to get there. I hate to imagine filling up my 45 liter tank out of soft drink bottles but it will probably happen:eek1

    If there is a definite path then that is it.
    After that if the ride continues then probably overland to India and then the rest is just speculation depending on how my personal and carreer life works out... (inbetween 'holiday' tours I'll be trying to do slabs of work in different countries).

    Anyway, food for thought,
    thanks.
  3. _cy_

    _cy_ Long timer

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    very useful information ... been worried about taking my 74 R90S to places with low octane fuels. sure is good to know your PD with 9.5 piston do well on 87 fuel.

    have you taken a compression reading yet? R90S measures 185 psi with a known to be correct Snap-on gauge.
  4. Wirespokes

    Wirespokes Beemerholics Anonymous

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    One of the regulars here, and I think he's Canadian, ran a simple water injection system that eliminated pinging.
  5. Stagehand

    Stagehand Imperfectionist

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    Nope. It'd be cool to find out, for grins.


    I guess i should say I havent heard any pinging over the sound of the valves :lol3
  6. disston

    disston ShadeTreeExpert

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    DAH. You are right Wrench. It should be one less tooth. :nod

    Charlie
  7. ontic

    ontic

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    Well, that was sufficiently interesting enough to spend an hour googling and reading.
    I think I'll start a new thread for that topic, not that I don't enjoy a good thread drift but that might be taking it too far.

    http://www.advrider.com/forums/showthread.php?p=17389601#post17389601
  8. Lornce

    Lornce Lost In Place

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    If you're seeing 185psi from a stock R90S you either have very serious carbon issues in your chambers.

    Or an inaccurate guage.

    :brow
  9. Lornce

    Lornce Lost In Place

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    Snowbum got me thinking about that after some discussion of WWII fighter planes and water injection to control detonation at full power.

    Worked pretty well. As a side benefit it was useful to steam clean combustion chambers. Which was my main objective. :D

    If you've ever taken apart an auto engine with a head gasket that leaked into a combustion chamber you know how well ingested water can work to decarbonise a running motor.

    :deal