Hey guys,

In Australia there is either Unleaded, E10 (up to 10% ethanol) or Premium Unleaded. I've always ran with standard unleaded because I heard premium and too much ethanol can be harmful to old bikes and cars.. Is this true? Should I put Premium in it instead?

Cheers

Hey Jonno,
I've always used premium in all my bikes (road and race bikes) without a problem. I stayed away from Shell Optimax mainly because I'd heard a few reports about the degergents within the fuel were no good for bikes (no idea how true the reports were, but would rather be safe than sorry when it comes to my engines). I have heard that since the NC30's and 35's were designed to be run on 93 or 95 RON (correct me if I'm wrong, which is most of the time), that running it with premium is a waste of money, but I don't have any complaints.

OK so I just read that higher RON rating = harder to burn, but provides more energy, therefore a high number is only for engines with high compression..

However, the Haynes manual states the RVF has 157-213psi of compression, so I'm guessing 98 shouldn't be a problem at all.. Haynes manual recommends minimum 91 RON, but doesn't state a maximum...

i ran RON99 on my vfr when i first got it to give the engine a bit of a clean out, but was advised that the bikes were originally built for RON91 in 1980's when the japs created them,

there was no noticiably differences with 95 or 99 octan apart from the cost,

i guess if dynoed youd see the difference.

No difference on a dyno. Did back to back runs on my XBR with Genuine 4 star, shell v-power and regular unleaded.

A higher RON doesn't mean any more power.

'Harder to burn' is a simple but effective way of describing it.

The higher the RON the less the petrol will 'pink' (pre-detonate) in the engine, which in turn allows you to have a higher compression ratio / harsher engine conditions (super / turbo).

These environments deliver more power, but if the fuel is of bad quality it burns before it is supposed to, which knocks the piston around and you hear the 'pinking' noise, which will evetually destroy your engine.

The US is the only place I can think of that still runs 85 gas in some states, probably alright for an old V8

Some of the modern vehicles like the BMW's are adaptive to fuel by use of a knock sensor, gives more / less ignition advances depending on the quality of the fuel.. which is why BMW quote something liek 240bhp for 99 fuel, 210 for 95 gas.

So unless you've done some serious engine work you shouldn't need anything above 91 unleaded.

As for the detergents of super unleaded.. bikes run clean anyway, providing you dont let fuel evaporate and gum up the carbs (of which super unleaded wont fix anyway) your carbs wont go dirty unless you get bad fuel.

The engine internals are cleaned by the oil and providing your mixtures not super-rich the valves and pistons are going to stay clean anyway.

Stripped quite a few engines over the years and all but ones with problems have been really clean inside.

Old Side-valve engines that specified a regular 'de-coke' are a different matter though!

As for Ethanol fuel, havn't seen any here in the UK. I'd stick with normal 91+ gas

Neosophist wrote:As for Ethanol fuel, havn't seen any here in the UK. I'd stick with normal 91+ gas

Yeah, ethanol's a bit dodgy. It's only called E10 in Australia because everyone kicked up a stink when cheap ethanol was added to fuels without telling the customers. Nowadays, they can't add any more than 10% and have to label it. Bad for some (older) plastics and rubbers, so I'd steer clear of that stuff for sure.

Personally I've used Caltex 95 RON for about 10 years in my VFRs and as Ronin says, Shell Optimax has a bad rep (maybe unfounded) so I avoid that. Certainly doesn't do any harm running 95 RON over regular, and as a bonus I can dump it into my car when I need to drain the tank/carbs

What is regular gas in Aus?

In the UK regular is 95, 98/99 is super/premium.

I use bio-fuel. A 50/50 mix of diesel and veggie oil

Neosophist wrote:What is regular gas in Aus?

In the UK regular is 95, 98/99 is super/premium.

Yep, same in Aus. Very 'dodgy' places may be less than that though....

I would steer clear of ethanol added fuels for now in older bikes. The last press releases I saw from a couple of the big Jap bike manufacturers did not recommend it, and some sound reasoning behind it (these bikes were never intended for ethanol in the fuel supply when built 20 years ago, probably not a great long term move to start using it now!)

viper_biker wrote:I use bio-fuel. A 50/50 mix of diesel and veggie oil

Funny you should say that Viper, ever since I bought a diesel car I've been on the lookout for unclaimed roadkill to take home and turn into fuel.*

A penny saved is a penny earned as they say...













* I think I need a bigger boot for all the dead roos etc, or maybe a trailer....