Hawk and higher octane fuel
 

Just wondering why it is recommend to run at least 90 octane fuel in our Hawks. From what I know about the octane rating is higher compression engines need the higher octane rating and the rule of thumb is if you can hear a knock or chatter (spark knock) then run the higher octane fuels. Also it's been said that the Hawk was designed to run in Africa, Spain and other countries and was to be a work horse, so to speak, with little maintenance needed. Now I'm not well traveled but I am wondering how accessible higher octane fuel is in these countries. I've been running 87 octane in my Hawk for the last couple tanks and haven't noticed any difference in the way it runs or sounds. I want my Hawk to last many years because it's just plain fun to ride and was wondering what everyone's thought is on this. Weigh in and let me/us know your thoughts. I know there people on here much more knowledgeable that I am and maybe I'm just thinking wrong.

I think it's because they are using the Chinese "RON", compared to the US standard of "AKI" testing... just another thing that was never properly "Translated/Converted by distributors/manufacturers before sale to the public"

If I remember correctly, 85 AKI is comparable to 90 "RON"... just some food for thought ;)

I use 87 every time I fill up my (current) motorcycles... 99% of the time it's corn alcohol laced crap too... a few times I have used 85... but up here at 6,000+ feet, 85 is the common number for "regular"... and on road trips I'm a little less snobby on gas/fuel treatments, just make sure it's "Top Tear" and not a run down gas station if I can help it... it will be used up shortly after all :hehe:

Hawk / Magician 167FMM engine Octane fuel use - 87 (US market)
 

Thanks for posting Octane "translation", i.e. Chinese 90 = US 85, more or less?

I do not recall seeing any Octane warnings on previous motorcycles, but then, maybe it just never jumped out at me? I have always used 87 Octane...
(In cars, prior to computer controlled ignition, you would sometimes get a pinging when stressing the engine, due to lower Octane. If you drove sedately on lower Octane, no ping.)

Hawk (Magician) User's Manual, pg 25, has this warning... which really raised my eyebrows:
"Using a lower octane gasoline can cause severe damage to the engine."

Net: unless others say different, I'll stick with using 87 Octane in my Magician.

http://therps.net/User%20Manual/Hawk...s%20Manual.pdf

No, you are not thinking wrong. To my mind, the only reason to use higher octane fuel is if it is not ethanol polluted. Ethanol gas is ok if you use a tank a week, or more. We have a lot of ruined outboard motors, lawn mowers, and weed whackers around here from the stuff. The fuel itself isn't that bad, it just has a very short shelf life. It goes bad real quick, in other words....ARH

I want to clear one thing up. The US does not use strictly RON for fuel rating. We use the average of the RON and MON knock indexes. That is why you see RON+MON/2 above the octane numbers at every station in the US. 98 Octane RON is equivalent to around 93 US octane. 95 Ron is roughly 91 US octane, and so on.

Also, Compression is just one of many factors that can determine octane rating. Ignition timing is another one. That said, it is a good general rule of thumb. I have always stuck to running 91 octane on every air cooled engine I have ever owned, and they have always run much better with it. That is why you will see "highest octane available" usually stuck in the spec sheet somewhere when it comes to recommended fuel.

I use the high octane to avoid the ethanol. Where I buy my gas the pump has a label that reads "NO ETHANOL IN OUR 92 OCTANE GAS".

Here in Florida all grades have ethanol in them but a lot of the newer stations are starting to carry ethanol free because of the large number of boat owners in the area so I run 87 octane ethanol free since I had some fuel related issues from the ethanol.

I stay away from the corn mash fuel. I often wonder if the guys ever test a batch of alcohol from the huge stills the old fashioned way...

Same here. With the high humidity the ethanol fuel turns to crap quick. I use to work on outboards and small gas engines and a lot of the issues with these motors was ethanol related. I personally run 89 octane ethanol free in all my small engines including the Hawk. I have run ethanol fuel but I knew I would burn through most of it that day and filled back up with ethanol free fuel.

I am in this camp. When I commuted the 33 miles a day on my TMEC 200, and currently on my TGB, I can notice the difference, so pay the extra whatever it works out to for the 92 octane.

I run 91 ethanol free on both, my 61mm big bore GY6 scooter and on my 169FMM Shineray dual sport, both carburated, no issues so far.

I noticed that your Shineray has the same Mystef's hawk aftermarket cluster.Nice bike by the way.

Thanks, aside from the factory chain (it never stops stretching, I changed it for an O-ring chain), it has been a reliable bike, I've been commuting on it 60km daily with my wife on the rear for a year or so, 17K kilometers on the clock already. :tup:

Corn Mash has one good use, and I'm NOT going to waste it in my bike. :LoL:

Am I right? Hahahaha

Yes it does reduce emissions and lowers the BTU's gallon per gallon with conventional unleaded, but just like government mandated health care and the internal revenue service tax system, were probably stuck with it for good untill Rome falls.