Selecting the right fuel octane for your motorcycle

[HighBoater]

Thanks for the clarity. I have tried to read some "Expert" octane evaluations for my 03 919, only to be MORE confused. Compression is 10.8:1 and my GF's FZ1 is 11.4:1(so of course I have to put Pre in her tank). Turns out that she is getting no real benefit from Prem. Go figure.

I am now on 87- no ethanol, but has to be from a clean source. It will take a while for me to convince her to switch.

[mrmaxstorey]

@HighBoater Right on sounds like a good decision. Really, whatever is recommended in the owners manual should be convincing enough...

[720moorhsum]

my compression ratio is only 7.6:1, but the owners manual specifies premium

[mrmaxstorey]

@720moorhsum Well there you go then. Im sure they have their reasons

[WordsofWisdom2010]

Hey Great Video! i just bought my first bike on saterday and i was thinking about this. but i have a question. Here in British Columbia, our lower octain fuel has 10% ethanol, is this something i should be avoiding or does it matter? im riding an 07 Honda rebel 250.

[mrmaxstorey]

@WordsofWisdom2010 Yeah we have the same ethanol down here, its my understanding that the same rules for selecting octane levers should apply, ethanol doesnt really damage anything, just robs a little horsepower. Consult your owners manual for what octane is suggested

[walkerrog25]

brilliant stuff this max, thank you bud.

[mrmaxstorey]

@walkerrog25 no prob dude

[skinz1234]

Hey MAX just a quick update from Germany. Havent been working on bikes cause its -15 degrees we got a siberian front coming through!!!!!!! SCREW BEING OUTSIDE :) KEEP UP THE FANTASTIC WORK WITH YOUR VIDS IM ALWAYS STOPPING BY :)

[mrmaxstorey]

@skinz1234 Sounds miserable! Over here, winter is already over!

[rossaus]

This is great video, Thank you. Here in Australia, they sell 91 octane with 10% of ethanol in it at some petrol stations. Do you know anything about ethanol is it good? I read that you can travel less with ethanol in fuel.

[mrmaxstorey]

@rossaus We have the same over here, most people recognize ethanol as a cheaper and less efficient fuel source. It does seem to rob a certain percentage of hp, and ethanol breaks down faster than gasoline, resulting in quicker gumming up of carbs and fuel pumps. However, its what we have, so we gotta live with it.

[gagelooney]

@mrmaxstorey Would you recommend getting non-ethanol gasoline if it was available? I have a gas station in my city that sells 91 octane with no ethanol added. I have been buying that for my CB450 after hearing somewhere that fuel with added ethanol is worse for smaller engines. Keep up the video posting. I watch every one of them!

[mrmaxstorey]

@gagelooney Well, yes and no. There are stations here in Tallahassee that sell non-ethanol gas, and sometimes we pony up the extra cost if we are going street racing or whatever. However for every day use it is in my opinion not necessary. Ethanol doesn't hurt your engine, just robs a little horsepower and decomposes quicker (for instance if you left gas in your tank/carbs and left the bike over winter). Some guys would disagree, but for your bike regular ethanol gas is fine.

[haha48]

higher octaine gas also burns hotter it can cause more wear on an engine on the vavles as well..

[anthonysoto29]

i go to mmi in phoenix, we just went over this stuff like 2 days ago! love the videos man keep them comin

[mrmaxstorey]

@anthonysoto29 Right on did you learn anything in class that I should annotate into the video?

[Michiganborn1969]

Great presentation Max. on my last bike, '85 Maxim 700, If memory serves, under the side cover that gave specs like plug gap & valve clearence etc it said octane rating 91 minimum & the comprestion ratio was something like 9:1 & the tach redlined at 9k. So MAYBE I wasn't wasting my money all that time???

[mrmaxstorey]

@Michiganborn1969 Yeah manufacturer's specs are always your best bet

[metalsapien]

thank you so much for these videos! your a true bad ass.

[atotheroh]

Hey, I have an '81 VIrago! Haha, glad that came to your mind first. Its actually my first bike, still workin' on it. Any general opinions about viragos?

[mrmaxstorey]

@atotheroh Haha it was just the first bike that popped into my mind. Viragos are ok by me, once you get past that whole starter gear thing most people find that they are very decent bikes

[angelocardoc]

Your right when you say that octane doesn't give you more power, but it's the lack of ethanol in the premium gas that does give you more power (about 2.5% more)

Regular gas (87 octane) has 10% ethanol.

Mid-grade gas (89 octane) has 5% ethanol.

Premium gas (91 or 94 octane or higher) has no ethanol.

Ethanol has less BTU's than gas. (Less omph!)

You will get more power from premium fuel but that's because there's no ethanol in it.

2.5% more power is hardly noticeable on most bikes.

[mrmaxstorey]

@angelocardoc Well I can't speak for your location, but most stations down here put ethanol in all of their grades of gas. We have a small list of stations that still offer ethanol free gas, but their stuff is generally more expensive. Perhaps I should have annotated this video to include a discussion on ethanol... it was long enough as is. Maybe a sequel.

Thanks for the info!

[lauriejennifer]

Great vid! When I use 87, my motard has awful, awful pinging. But, I notice no difference between 89, 91, 93, etc. I've noticed this since my big bore and flat slide. I get nasty pinging with "regular" pump 87.

I don't know what the ratio is supposed to be with the big bore. I know this particular kit is intentionally designed with a bit more gap in the piston and rings, because of heat expansion or something. It always fails compression and leak down tests when cold, not when hot. *shrug*

[mrmaxstorey]

@lauriejennifer Whats the compression supposed to be? How much are you getting?

[lauriejennifer]

@mrmaxstorey I am not sure what numbers I should be getting, but I can ballpark what I'd expect a high performance overbored single to get and it's not 108psi. LOL It was in the 106-109 range when cold. And you can *hear* the air rushing past the rings. Scared me my rings hadn't ever seated right, until I was assured by manufacturer that this kit was designed that way intentionally.

[mrmaxstorey]

@lauriejennifer Bummer! If thats the way it was designed it doesnt sound like the design is doing its job

[lauriejennifer]

@mrmaxstorey Yeah, something about how that's better/safer for the cylinder with the big bore. The poor thing is bored out 102cc's, after all...

The one thing that makes me nervous is how my bike still runs like sht once fully warm. Wandering idle, bogging, and then dying. We changed the pilot jet and otherwise adjusted the carb and it's a million times better... but still acting like a vacuum leak.  Time to start replacing o-rings around and in the carb, just for shts & giggles.

[mrmaxstorey]

@lauriejennifer Its my experience that poor compression can't ever really be compensated for by any other system, ie richening, leaning, performance spark plugs, etc. However I wouldn't know about this, never used a kit like that before.

[lauriejennifer]

@mrmaxstorey Same. I'm not attempting to compensate. I'm just trying every other alternative before I go blaming compression. I don't want to tear down my top end for the third time in six months, you know? So, I'm fiddling with jetting, checking for air leaks, etc. first.

It was running too lean. Now it's a bit too rich (40mpg? black plug? black exhaust tip? Obvious fail is obvious). I give up on jetting tweaking until I can dyno this thing, remove guess work.

[mrmaxstorey]

@lauriejennifer OK I hear ya well be sure to let me know how it goes sounds like you are doing a good job narrowing down the possibilities

[lauriejennifer]

@mrmaxstorey Will do! It's been a great learning experience, for sure. I knew almost nothing about engines, carbs, etc. when this all started. At least it's still rideable (though it stalls at long lights once you've been riding for 20-30 minutes). In the mean time, I am absolutely LOVING this process. I'd say that makes me crazy, but you seem to share the insanity.

[mrmaxstorey]

@lauriejennifer Oh for sure man the joy is definitely in the process.

[bityard]

Your videos are like Khan Academy for motorcycles. Awesome.

[mrmaxstorey]

@bityard Thanks thats actually a great compliment

[spelunkerd]

New vehicles have electronic ignitions, that allow the computer to adjust the timing of spark depending on rpm, air temp, and many other variables. Therefore I am no longer surprised to see that although premium gas did work better for my old '63 chev, it doesn't help at all for modern cars. I completely agree with your assessment, and I'm glad to see a review of octanes for motocycles. It runs parallel to other reviews here on youtube.

[mrmaxstorey]

@spelunkerd Yeah I was thinking of getting into turbos, variable altitude, computer assisted timing adjustments, etc but the video was long enough... perhaps in a sequel

[mrmaxstorey]

@Petr074 Hey dude if I were you I would cross reference "regular gasoline" and confirm that it means 87, but that does seem to me that your bike was made for lower octane gas.

[SirSeanSean]

Really enjoy your videos. 

[TechHost]

my 06 ninja 650 has a compression ratio of 11.3 to 1. what do you think?

[mrmaxstorey]

@TechHost 87, unless your owners manual says otherwise of course

[ilikesuzuki]

@mrmaxstorey thanks man great video it's really helpful.

[formegolf]

Nice vid Max great info

[mrmaxstorey]

@formegolf Thanks Mark

[BAXMAN68]

That was a very well constructed video. Thank you for ALL of your great videos :)

[mrmaxstorey]

@BAXMAN68 Thanks man

[MrGhirbo]

12:46 starts the conclusions of the video. Thanks for video! i like to watch and learn from the pro's.

[mrmaxstorey]

@MrGhirbo Haha yeah I know this was a long rambling one