Aus XR650R Needs special fuel to run okay

1 reply to this topic
  • Mark_Bear

Posted April 13, 2007 - 01:27 AM


Hi all

It's a long time since I posted here. I haven't riden the pig much due to hot weather and having the luxury of a road bike available as well.

The reason for the post is I have had trouble starting the pig since new. I've run premium unleaded, which has a rating of 98 ron (Oz remember). This is what the owners manual recommends.

Now after checking everything again, keeping in mind that it has only 3,000ks of mostly street kilometres on it, I found a completely sooted up spark plug. I heated it with the gas torch to remove all the carbon and stuck it in back in the pig. First kick and away it went. By this stage I'm ready to sell it due to this, I love the bike but It has never started well, sometimes not at all. I now think i know why it is not the same in the US.

I took it to the Honda dealer and told him I was over it. He asked me what was up and then we got chatting about my concerns. It appears that premium unleaded in Australia is only good for fuel injected and computer controlled engines. He recommended that I try some Mobil 6000, which he claims has additives which are more suited to carby and older engines. It has a Ron of 95 (Aus, which is a different rating than US) which is plenty for the piggy (so he says)

Keep in mind that this is not what is recommened by Honda in the manual which clearly states 98 ron, and converts to 94 Octane using the US scale. The one I'm now using is 95 Ron or 91 using the US scale. I found this in another forum which seems to explain it beter than I can;

91 octane AKI is 87MON 95RON fuel (87+95)/2 = 91
93 octane AKI is 89MON 97RON fuel (89+97)/2 = 93
94 octane AKI is 90MON 98RON fuel (90+98)/2 = 94

So....I drained all the old fuel, and filled it with Mobil 6000, fitted a new plug, and it started first kick. It has not missed a beat in some 800'ks on the new fuel, no coughing, stuttering, crappy running hard to start...all gone, just runs nice.

If you are having problems (in Aus) then give it a try, worked wonders for me.

I love my pig again...

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  • motopsycho650

Posted April 13, 2007 - 02:53 AM


I have no idea what ron & oct ratings equal each other. I know my pig will not even start with anything less than 91 oct in it.

I guess it is possible for certain fuel to not work well in carbs. If it does not mix with the air & atomize well, I bet you'll have some issues. It's interesting to hear how your fuel works a bit differently. Glab to also hear you didn't give up on your pig just yet.

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