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Thread: Fuel

  1. #1


    G'day all, I will ( hopefully ) be back in Aus soon, and the first thing I will be doing is firing up my 83 1100. What's this got to do with fuel ? Well, the bikes been in storage for over ten years, just sitting on it's centre stand gathering dust and spider webs. After doing all needed to get her going, what fuel do you use nowadays in our Kats ? In other words, what bowser do pull up to at the servo.
    onya guys, rangerkat.

  2. #2
    Be prepared for the carbs and probably fuel tap to piss fuel everywhere.
    I run 98, but that's because it's got a bunch of compression over standard. 95 should be fine.

  3. #3
    Yeh 95 is all good for my basically standard 11.
    I always try for BP as it seems to run the best in all our vehicles, other folk may be different though.


  4. #4
    In Japan, people can choose from only two grades in choosing petrol at the servo. Clear display of octane number is not done on any servo, but the high octane number grade is about 98〜100 and the normal grade is about 90〜91. I choose the high octane number grade in my Kat. The reason is why noise is heard from the cylinder head, when I use normal grade in hot summer days and open the throttle quickly wide. The noise is "chiri chiri chiri chiri........"

  5. #5
    Senior Member WA ThomasJ's Avatar
    Join Date
    Oct 2014
    Golden Bay WA
    I use 98 and been recommended to use a fuel additive for valves. Anyone else do this?
    Preservation over restoration - they are only original once

  6. #6
    Quote Originally Posted by ThomasJ View Post
    I use 98 and been recommended to use a fuel additive for valves. Anyone else do this?
    I don't use a fuel additive for valves. Probably no Japanese Katana owner uses fuel additives for valves.

    Quotation from service manual: Gasoline used should be graded 90 octane or higher. An unleaded or low lead gasoline type is recommended.

  7. #7
    They have hardened valve seats from factory, valve saver additives are not needed.

  8. #8
    I think you'll find that motorcycles manufactured in Japan from sometime in the 70's will all be made to run on unleaded fuel, I use 91 and don't have a problem, my compression is approx 10.5 to 1 (stock is 9.5 to 1).

    I find 98 a waste of money.

  9. #9
    Moderator QLD Shin-Ken 1074's Avatar
    Join Date
    Oct 2014
    S.E. QLD Australia
    Yep, stock OEM motorcycle 4 stroke engines made in Japan beginning in 1976 were designed to use Unleaded 91 RON fuel. Not saying it's the best fuel to use, only that the engines were built to run on 91.
    Badgezz, we don need nor stinkin' badgezz!

  10. #10
    Senior Member NSW GSX1100dreamn's Avatar
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    Nov 2015
    West Ryde Sydney
    To add to Ben's comment exactly, For Australians any vehicle manufactured from 1986 had to run on unleaded fuel. Technically any 4 stroke engine with an alloy head has to have hardened valve seat inserts otherwise the valve would pound and damage the relative soft alloy. On the other hand engines with cast iron head can have the valve seat machined as part of the casting 'but' you have to run a lubricant e.g lead or now in the form of an additive, conversely you could get hardened valve seat inserts installed into your cast iron head then allowing you to run unleaded fuel without an additive. As for lubricating hardened valve seats fuel manufacturers use wax and shellac. Older engines pre 1986 were made to run on the fuel available at the time, I'm talking standard and super having an octane rating of 87 and 93 respectively, that's why when unleaded fuel came out having 91 octane we used to just retard the base timing a couple of degrees on some engines to eliminate pinging. The Japanese car manufacturers were making alloy headed engines decades before the Aussies thus the conversion was straight forward change no additives or engine mods. Ok class back to our Kats. Cheerio Andrew.
    Last edited by GSX1100dreamn; 24-02-19 at 09:41 PM.

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