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2 noob questions: fuel and 5th gear

Discussion in 'New Riders and Riding Tips' started by guggle, Jan 18, 2011.

  1. Hi all,

    A couple of ignorant questions for you...

    1. What type of fuel is best in a 250 road bike? There's usually a choice of 3 different types of fuel available at most servo's and I was wondering what type of fuel most people put in their bikes?

    2. A question I forgot to ask when I did my L's a last week was is the 5th gear on a motorbike an over-drive gear ie. is the ratio less than 1:1. Would you use it to go 60km's an hour or stay in 4th?

    Cheers, Michael.
  2. The type the manufacturer says should go in it,
  3. Premium fuel (98 Octane) should be best for your engine and get the most kilometers per litre. Beware fuels with ethanol in them (such as e10) if you don't ride your bike every few days, as ethanol is known for making plastics and rubber brittle after sitting still for long periods of time (months, even years).
  4. 5 gears.... you mean 6

    and they aint overdrives
  5. If the manufacturer specifies at least 91 octane, run that unless you get engine knocking.
    You dont get any more power out of higher octane fuel, it is just harder to ignite - needs higher compression so less prone to pre-ignition (knocking). Its a well developed lie that you get more power from higher octane fuel, its all about compression ratios (eg, running a 91 octane fuel in a high compression sports car, you are more likely to damage the engine due to pre-ignition). Running higher then specified wont hurt, however some carby fed engines are a bit picky, and you may need to retune the carbies.

    Most 250s have the 1:1 gear in 4th i think (pretty sure mine does and a couple others ive been on, hardly a wide variety to base my assumption on). Short of knowing precisely what bike you have and access to the service manual, thats probably about right. Most bikes have 6 gears, though some do have 5. Nope, not overdrive :p just another plain old mechanical gear!
  6. i use the 6th gear when riding at 60, keeps the revs a around 5k on a balius. although got recommended not to use higher than 91 as it stuffs the timing.. although never heard of this happening in a car and ive always run 98 in my car.
  7. +1 - in a 250 you'll get what amounts to "clogging" in your jets.
    Nothing higher than 91 if you can help it (95 is OK in an emergency, but don't fill it...), and NEVER use ethanol blends.
    I'd still be putting Super in mine, if I could get it ;)
  8. Use whatever the owner manual says - typically 91RON for 250's. Despite what Hack says, an engine NOT DESIGNED for higher octane fuel will NOT get any economy benefits from it. You MIGHT get some system cleaning benefits. You MIGHT also get some rough running since higher octane fuels tend to be more dense.

    Some budget 250 bikes have 5 gears, most other bikes have 6. There's no over drive. Top gear is 1:1
  9. It's a "sad but true" fact that some bikes only have five gears. Like the KLR650 for example.

    OK, stop laughing.

  10. And some biggies like the FJR1300 so don't worry.....
  11. After reading Rob's comment I checked my handbook and what do you know? For the KLR, Kawasaki recommends fuel of at least 87 RON.

    What the!

    I'm going to give 91 a go, just for a tankful, and see what differences I get.

    I have been using 98 RON BP Ultimate, and she has been running a little bit rough ... even for a thumper.

  12. #12 MrJimmyC, Jan 20, 2011
    Last edited by a moderator: Oct 24, 2015
    Bloody near impossible to get 91 octane fuel without it being ethanol blend nowadays. At least where I live in western sydney.
  13. 87 RON is the American version of Australia's (and almost the rest of the worlds) 91 RON.
  14. Erm...what's the big deal with gearing? You ride in a gear that suits the conditions, that could 4,5, or 6th if you had it.

    You don't want to be screaming the engine, have it bogging down either. Feel free to change to an appropriate gear anytime it suits the traffic flw or your comfy speed. :)
  15. Not quite right. The Americans use AKI, which is an average of RON and MON for a particular fuel. What it means to us is that their numbers are about 3-4 units lower than ours for the same fuel.

    In Western Europe, in general, their basic fuel is called Euro95, our "premium unleaded" and this is why all Euro spec vehicles will require "premium" in Australia. There are some vehicles with modified tunes imported, read the mass market vehicles, that will be happy with our 91/92 octane standard unleaded.

  16. I dunno Garry, but did you say something meaningfully different? lol

    Welcome to NITrider, you'll do well here. :)
  17. Ya know what, I guess I didn't. Must have been too late at night.

    No idea what I thought you had said......


    At least I can laugh at myself now.........the floods are gone.......

    ps just worked out what the difference was, American fuel is not measured in RON, but AKI, so where you said US 87 RON was etc etc etc.....it is 87 AKI in the USA
    so, no maybe not meaningfully different :) Just different
  18. Is there anywhere that sells 91 WITHOUT ethanol - i can't find it anywhere (near sydney CBD or even surrounding suburbs)
  19. Yep, in states other than NSW or QLD.
    You can thank your former state Government for that.
  20. It's still around Di, but increasingly rare at the major players.
    I get it at my local independent in Kogarah...