Fuel for your WR

Well I did a search on fuel and could not find too much on the topic. This discussion was also raised at 400thumpers.com

Shell in Oz have a fuel called 'Optimax' which is a High Density High Octane unleaded fuel.

This fuel is basically a higher mass of fuel that is packed into the same volume. A tank of this actually weighs more than a tank of premium unleaded and therefore has more fuel available for combustion,supposedly resulting in better fuel economy.

Shell claims that it vapourises and ignites more readily and burns more completely. This improvement translates directly to a more efficient combustion, the most tangible result I've noticed being a more responsive engine.

I guess the high octane is perhaps the most obvious performance enhancement as it has a 98 RON .I think most other Premium unleaded fuels typically rate at 95 RON dependent upon the manufacturer and state controls.

I use it in my bike and don't have any problems.. in fact it runs great, never fouls plugs and seems to help in delivering a nice crisp throttle response.

I'm just curious to see what fuel other WR owners are running and what possible effects (if any) different fuels have caused in your

bike? How much does petrol differ internationally?

I've also ran super (which is leaded) and regular unleaded. I noticed nothing radcially different in the response of the bike, except that the Shell Optimax seemed rev a bit cleaner and there seemed to be less carbon build up around the end of the muffler?

The sticker on the tank said unleaded fuel only..I'd say this is to comply with ADR (road compliance) but are there any ramifications of running anything else?


I always just use whatever premium unleaded is available at the gas station where I happen to stop,and I have never had a problem or noticed any sort of performance enhancements with one particular fuel. Interesting to hear that you can still buy regular leaded fuel,that stuff has been banned in Canada for years.

I recall reading in a couple of rags to NOT use "race fuel" in these bikes. Race fuel LOWERS engine temperature due to a lower flash point. Race fuel, due to it's stringent standards, also provides the best feedback for jetting purposes. It never varies in octane #'s or additives.

Now, WHY is it not good to run race fuel or a 50/50 with premium unleaded pump fuel (U.S.)??


'99 WZ with ALL YZ mods, de-octopused, DSP Doug Henry airbox w/ velocity stack, FMF PowerBomb header, Stroker SX-1 silencer, SS front brake line, forked over by Pro-Action (and then fixed by me), OEM YZ tank, IMS YZ seat, carb mods by Jim Dean, Andy in OZ, & Sir "Taffy" from Jolly Old England, AMA, NESC.

Good subject. You are so lucky to have 98 octane gasoline. Here is California we have some really weird fuels. Sometimes I wonder if it really is gasoline. Is says on the pump that premium ($2.20/gallon) is 92 octane, but ya gotta wonder. Oh well, the stuff burns and my bike runs on it. I'm not sure about the performance differences between our "summer blend" and out "winter blend". Yes, we have different blends for the seasons. It's far too confusing to figure out, but I do know that "they" put Methyl Tertiary-Butyl Ether (MTBE) into the fuel to reduce air pollution. The same stuff pollutes the drinking water supply. Go figure.

If you want more info: http://arbis.arb.ca.gov/cbg/cbg.htm

Ron,isn't to-day a holiday down there? Why aren't you out riding?I assume by how little activity there is on the B.B.that most of your fellow Americans are out riding,or at least they're not at work.

Pete, you are very observant. Here is the current state of my WR:


I've got my suspension parts in the shop getting re-valved. Besides, I usualy take the big holidays off. Too many people riding around after consuming certain beverages and acting like idiots. No thanks. Oh well, back to the garage for me. Tinker time!


whats wrong with that?? just pop her up on the rear wheel and off you go! LMAO :)

Thanks for the blurb on Methyl Tertiary-Butyl Ether.. hehehe I must talk to my missus about that one! :D

Interesting to see that you pay around US$2.20 per gallon for your premium. We use litres here and that equates to around 4.54 litres for your 1 gallon. Given the exchange rates its works out to about $1.00 per litre which is pretty much what we pay here. (on average)


Hey Curt, is your bike stock or altered and what state are you in. Because I was wondering if the different state of tune and or altitudes has anything to do with why my bike hates Opticrap and yours doesn't. My one is a bog stock 99'r with the air box lid removed and I ride east and south east Vic.

It runs well on it then suddenly the plugs stuffed, I have no problem with any other fuels.

The general sences seems to be you either love or hate it depending on your paticular bike.....


Yeah I hear you Cambo, but am at a loss to explain why? I ran the stock pipe on it for about 6 Months and then put a 2000 YZ426 muffler on it.

I ran Optimax in it from the day I purchased it.. I guess if your chopping and changes fuels a lot it might effect it, but doubt it. Id probably put it down to the bike maybe running too rich? With the wealth of knowledge on here Im sure someone could answer it. Im not really one of those guys that tinkers with everything.. I like to wheel her out, ride the ass off it and put it back away... (why did the thought of my missus appear in my head then? :))

I ride the same areas as you do in VIC. **** I remember having to fill it up at Woods Point with Super and it ran smooth as silk. Just not 'as' responsive I guess.


I had been running Amaco 93 in my WR426. The last ride out I couldnt find a Amaco Station so I settled with Citgo 93. Well the other day I went to start it up and I kicked and kicked and kicked...changed shoes due to a hole I made...and kicked some more. That gas SUCKED. It fouled my plug BAD. I believe it was 87 that they threw in the 93 tank. With the way gas prices are I wouldn't be suprised. Anyway from now on I'm going to make sure It's either 93 Amaco, BP (one in the same) or Chevron

For whats it's worth, a friend of mine has only used Turbo Blue, 110 octane, in his 2000 YZ 426 and has never had a problem.



2001 WR 426, YZ# Plate, YZ Fender, YZ pipe, YZ Tank, SDG YZ Seat, 13/50 Gearing, Pro-Taper Bars, TAG Triple Clamp, Throttle Stop Trimmed

The advance gets to be important with octane changes. It may be worth checking the TPS setting on the WR that doesn't like the higher octane. It is also possible that the compression is down a little--my bike runs smoother just before I need new rings so much so that last time I added an extra base gasket to drop the compresion a little, I have avoided optimax since. The bike runs quite well on regular unleaded and is just a little cooler on premium, not a problem at the moment SEQ is getting quite cool. Allen rang from Townsville last night to say he had to get out a blanket, must have dropped below 20C one evening . He tells me that winter came on a Wednesday in Townsville last year.

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