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  1. #1
    ...a racing we will go...
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    What manual says about 1989 TZ250 fuel



    a d v e r t i s e m e n t

    I recently purchased a 1989 TZ 250. The previous owner has it jetted and says it runs well on VP C12 so I just bought 5 gallons of it. He also gave me several bottles of Castrol A747 so I will continue to use it also. I have been reading the many posts about fuel here and this seems like a good combination so this is what I will use.

    There is some very interesting information in the maintenance manual for the bike. For the fuel it says: "Recommended fuel: Except for Australia; Premium fuel with an octane rating of at least 90. For Australia Unleaded fuel only." It also recommends Castrol A747 at 30:1.

    I am a little surprised that so many TZs are being ran on fuel with considerably higher octane than the 1989 manual says. Is it because the newer TZs have higher compression ratios or many are rebuild with parts that give higher compression? I agree pump gas is probably not a good idea because of the variability and the ethanol in some/much pump gas.

    The manual does not say if the 90 octane minimum rating is R+M/2 or MON but in either case it is way lower than VP C12 at 108 MON.

    Also the manual seems to lean toward unleaded, but C12 as well as many race fuels are leaded. Again does this depend on motor set up at rebuild?

    I am not planning on changing away from C12 and A747 soon. Maybe at the next rebuild. I am just trying to reconcile what the manual says compared to current practices.
    Last edited by daveb; 01-20-2016 at 08:39 AM.

  2. #2
    ...they call me the rocket man... ndwedwe's Avatar
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    Apr 2012
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    Mid Wales, UK
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    334
    my understanding is before 1994 or so the race bikes all used 100/101 low lead avgas
    i dont own a 1989 TZ but i run my 1993 on avgas
    it is a far safer fuel
    i expect you should hear a lot of opinions coming through
    1993 TZ250
    1999 TZ250

  3. #3
    ...laterally accelerating to a track near you...
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    May 2002
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    These motors were designed for leaded fuels so unless you cant buy any then no point in going through all the hassle of changing loads of things to run unleaded. Don't forget that the lead also acts as a coolant. If you just chucked in U/L fuel into a bike set up for leaded you will wreck the motor.

  4. #4
    ...i smell a trophy...
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    Quote Originally Posted by daveb View Post
    I recently purchased a 1989 TZ 250. The previous owner has it jetted and says it runs well on VP C12 so I just bought 5 gallons of it. He also gave me several bottles of Castrol A747 so I of coarse I will continue to use it also. I have been reading the many posts about fuel here and this seems like a good combination so this is what I will use.

    There is some very interesting information in the maintenance manual for the bike. For the fuel it says: "Recommended fuel: Except for Australia Premium fuel with an octane rating of at least 90. For Australia Unleaded fuel only." It also recommends Castrol A747 at 30:1.

    I am a little surprised that so many TZs are being ran on fuel with considerably higher octane than the 1989 manual says. Is it because the newer TZs have higher compression ratios or many are rebuild with parts that give higher compression? I agree pump gas is probably not a good idea because of the variability and the ethanol in some/much pump gas.

    The manual does not say if the 90 octane minimum rating is R+M/2 or MON but in either case it is way lower than VP C12 at 108 MON.

    Also the manual seems to lean toward unleaded, but C12 as well as many race fuels are leaded. Again does this depend on motor set up at rebuild?

    I am not planning on changing away from C12 and A747 soon. Maybe at the next rebuild. I am just trying to reconcile what the manual says compared to current practices.
    From an Australian point-of-view...the manual will state that as leaded fuel has been banned throughout Australia for 30 odd years. For a while, you could buy leaded Avgas but had to have a "leaded fuel permit" booklet that had to be signed off by the retailer of leaded fuel. This has now gone the way of the dinosaurs so we have to use unleaded petrol (ULP) or - pay a substantial price to use fuels like VP etc which cost us over $8.00/litre (Yes that's over $160 for a 20 litre drum of VPC12). I agree with the others.....if you can get it, use leaded fuel where possible unless of course you want to change ignition settings, change your heads and squish and jet accordingly for unleaded fuel. Later model TZ's came with all the necessary mods to run premium ULP....your bike didn't :-)
    Steve

  5. #5
    ...a racing we will go...
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    a d v e r t i s e m e n t

    Thanks for the input guys.

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