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What fuel do you put in your bike?

Discussion in 'Maintenance and Servicing' at netrider.net.au started by Genabee, Feb 17, 2013.

  1. Please forgive my ignorance - I am new to this!

    A good friend who is a motorbike enthusiast suggested we should always put premium/98 octane fuel in the motorbike and where possible, always purchased from BP as it is the best quality.

    We have had reason this past week to be at the repair shop with the scooter for a fuel pump issue. The mechanic in there suggested to use 91 Octane and also suggested BP or Shell fuel is best to use. His reason was that the higher octane fuels are notorious for clogging up the fuel pumps of scooters and motorbikes alike.

    Our internet searches on this don't really suggest strongly one way or another.

    The girl in me tends to want to go with what the 'professional' mechanic says. But then I also have trust in my friend as he hasn't led us astray yet...

    So, what fuel do you use and why?

    We have a Honda CB400 if it makes any difference.
  2. I'd be more worried about running E10 in a bike that's not designed for it.
    Ethanol will gradually dissolve the fuel lines and carb seals on older gear and end up causing enormous headaches. It's not a problem if you replace everything with stuff that's compatible, an engine and valves that run on unleaded won't be harmed by E10 (E65 could well burn valves though) but the natural rubber used in old lines, slide diaphragms, seals etc will perish and turn to jelly when exposed to ethanol for long enough. 96 octane premium is more than enough for most engines though, there's no need to use the dearest possible stuff.
    A new bike that's designed to use ethanol fuels won't be bothered of course.
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  4. I'll give the mechanic this: higher octane fuels being "notorious for clogging" is a new one to me.

    I've routinely put Caltex 95 in my EFI car for 75 000 km without issue, the one before that as well as the two bikes prior to the couple of thousand or so km I've done on my current one, all without a single problem.

    The info I last looked at that Caltex provides mentions fuel system cleaner in their 95 and 98 premium fuels but not in their regular 91.

    I also just recently tried their 91 in my carbed bike ('95 Honda VFR), for the first time in years (and 1st time on this bike, as an experiment), and it felt laggier on the throttle, more lethargic and ran rougher enough to notice. And that was with roughly 10 litres 91 mixed with about 4L of premium.

    I siPhoned it out and put it in the car, while muttering a sincere apology, to dilute the crap's fun-cloying nonsense.

    That doesn't necessarily mean it would do any harm, but compared to their 95 and 98 it was crap, and longer term, keeping your entire fuel system clean is such good, simple prevention.

    My default suggestion remains to use 95 (Caltex/Mobil for me, and BP has seemed fine on occasion) with no ethanol, as long as it meets or exceeds the RON octane rating that the manual recommends. By that, I mean if it says it'll run 91, I still use 95 minimum (and most of the time, occasionally also 98).

    I'm willing to bet that the much bigger price difference between most regular 91 and 95 compared to 95 and 98 is down to lot more than just the octane difference, and the simple way I look at it is that 91 = poor quality enough of the time, and since you can't tell one that might be half decent when it's going in - Pass.
    • Like Like x 2
  5. Some of the high octane "super fuels", like the 100 octane stuff, is just slightly thinker than normal fuels like 91 regular or 95 premium. It's not enough to make any difference to a large engine (with large injectors/carb jets) but the itty bitty stuff on a small to mid bike engine seems to not like it (at least this is what I've been told). Personally I very rarely use the real fancy stuff in my car and normally run 95 RON premium, though I confirmed today that it's rated for 91 RON E10.
    Even on a vehicle I was happy to run cheap fuel in, I like to run premium on long trips to give it a clean out.
  6. Please... don't run E10 (or any Ethonol blended fuel) in your bike.
    (I would not buy a used bike if I found out the owner had been running E10 in it)

    Run what the manual recommends. Unless you have modified the engine.

    In my 1300 I run 95oct (and avoid Shell optimax)
    DR: I try to run 95+ because it has a High comp piston setup.

    If refuelling in a small one-horse town, use the most used bowser, most probably the 91. Then top up when you can.
  7. The SG (Specific Gravity) used to be on some brochures if you asked for them at a servo. When I looked at the MSDS (Material Safety Data Sheets) on the Caltex website a while back, it was also given, but (as I recall) only on the 95 and 98.

    My recollection from the brochure, maybe ten years or so ago, was that the regular had a lower SG than the premium of the time.

    On the less sophisticated EFI systems of the mid/late Nineties, at the constant supplied fuel pressure, it seems reasonable to suspect that a higher volume of the thinner regular fuel would pass through the injectors if the duration of their opening time wasn't altered to take account of the different fuel types. A few people with EFI Commodores and Magnas of that vintage were telling me their dash computers were showing notably higher fuel consumption on the regular grade fuel, which more than negated the price difference at the time.
  8. 91 E10 = Don't even think about using this in a motorcycle.
    91 = Basic, cheap, will run ok in some bikes though not recommended.
    95 = Recommended by most manufacturers, clean, reasonable quality.
    98 = premium quality if want to pamper bike, though not necessary.

    Some 98 fuels are denser than lower octane fuels which might effect mixture. Fuel injected bikes with oxygen sensor in pipe can compensate for this when in cruise mode, however when you open them up they resort to a pre-set map & may run rich. Some cars run knock sensors which allow them to advance the ignition timing to take advantage of higher octane & return better economy. I do not know of any bike that runs a knock sensor though, so 98 may be wasted on a bike. Carbie bikes may need rejetting /mixture screw re adjusting to run on 98.

    Never heard of better / higher octane fuels clogging up fuel pumps, unless the fuel is contaminated with dirt / water, which is no fault of the fuel, rather the problem lies with the service station storage tanks.
  9. Excellent summation, Tinkerer, although I'd suggest that some higher compression carbed bikes could use more ignition advance to take advantage of 98 as much as they would rejetting (but that's worth fettling too in most cases anyway).

    BMW has had knock censorship on its bike systems for a while now, and I wouldn't be surprised if a few other makes have it recently as part of their whole engine management suite on higher-end models.
  10. #10 Ballsy Mgee, Feb 17, 2013
    Last edited by a moderator: Feb 17, 2013
    I've got the same bike as you and most of the time I use 95

    - 98 is overkill for our bike (sometimes better for more modern technology and performance engines)

    - 91 is fine the bike runs well on this fuel

    - As others have stated --> don't use any fuel with Ethanol

    Sometimes is hard to get normal 91 without ethanol.. I just stick to 95 and it runs beautifully.
    • Like Like x 1
  11. Top Gear did a test of high octane fuel in cars. They found high octane 98+ is of benefit only if the engine is high compression and the engine management can adjust the tune to take advantage of the greater knock resistance, then the engine makes a few extra horsepower on 98. Otherwise 95 is as good as 98.
    • Like Like x 1
  12. This come up all the time
    Here is how it goes
    Any Euro EFI bike---> the higher the Octane the better
    Any japper EFI bike -----> Low octane good higher octane better
    Any bike with carby-------> use normal unleaded-> High octane fuel eg 98 can clog your carbies as it has detergents in it to clean the fuel system, these can clog your needles, efi bikes have a fuel filter.
    Any bike using e10--------> get your head read.
    • Like Like x 4
  13. BP 98 only, in all my cars and bike. Better fuel economy and power. It may be more expensive but in my opinion you get what you pay for.
    • Like Like x 1
  14. The prevailing perception in many online discussions seems to be that the sole difference between grades of fuel, let alone in fuels different countries, is solely the octane rating (which differs in the way it is measured too) and absolutely nothing else.

    It's a cocktail of indredients that comes into play in all sort of ways.
    • Like Like x 1
  15. I use unleaded (91) of the regular standard pump variety for my vstar and my Vstroms. The virago 250 gets premium 95 otherwise it pings on hot days. Anything else is a waste of money and good marketing by the fuel companies.
    • Agree Agree x 2
    • Like Like x 1
  16. Well what about e85 hmm?
  17. Me too. I used 98 once when I first got it out of ignorance and it backfired like a sonofabitch, so then I did some research and came back with pretty much what smee posted above. Since then, it's been regular unleaded 91 with occasional 95 if circumstances are right. Preferably Shell or BP.
  18. I don't think there's a single bike on the market that's rated for that. Period.
    If you happen to be a tree-hugging leaf-licker (ie over the top greenie) then it's possible BUT you WILL NEED to get thr right lines, pumps, seals, filters ... THE LOT and then re-tune to suit the stuff. If you're not prepared to go through all that DON'T TOUCH IT!
  19. I always run BP 98 in the bike, defiantly gets better mileage than running lower octane fuels, it still runs ok on 91 just doesn't achieve the same km's per tank
  20. My bike runs very well on 91. On the rare occasion when Ive filled her up with 95, she runs really badly, coughing and spluttering and accusing me of poisoning her. Ive put E10 in and theres never been a problem but Ive read how its not really suitable for bikes and so I now avoid that as well. Has to be 91 Octane here.