Topic: What grade of gasoline do you use?

[DammitDan]

I've found that premium seems to help the old beast to run smoother.  Maybe it's just my imagination though...

[ofreen]

I use regular, which is 87 octane around here - southwestern Idaho.  Works fine, no pinging.

Greg
'75 CB750F

[Hop on a Honda]

Fuel / Gas.
I would use 100 Octane avgas in every tankfull IF I could
There is no comparrison and it CLEANS the innards of every thing concerned.
Also it gets more MPG using the same throttle settings and has no gunk in the goo.

Our local fuel is terrible in the fact that its full of / and coats every thing in like burnt honey
I wondered how LPG would work?
Dave Australia.

[kghost]

Well, it really works better at a 50/50 mix.

Too much lead in the old 100 LL. About 5.5 parts per million.

[heffay]

your asking a loaded question dammit... dan... he hee....

too many vehicles to chose one octane...

cb350f- premium: the more preignition the better!
zx7r- midgrade: pings too much with premium
scooter- whatever i want... it runs on gas and oil does grade really matter?
74 j20 jeep- believe it or not manual calls for 91 octane!

[kghost]

your asking a loaded question dammit... dan... he hee....

too many vehicles to chose one octane...

cb350f- premium: the more preignition the better!
zx7r- midgrade: pings too much with premium
scooter- whatever i want... it runs on gas and oil does grade really matter?
74 j20 jeep- believe it or not manual calls for 91 octane!

Pings too  much with premium? WTF Hef?

[SteveD CB500F]

I would use 100 Octane avgas in every tankfull IF I could
There is no comparrison and it CLEANS the innards of every thing concerned.
Also it gets more MPG using the same throttle settings and has no gunk in the goo.

We should get Lloyd (TwoTired) to comment on the various Old Wives' Tales about premium vs regular fuel...
Any chemists out there tell me what they put in Premium that actually cleans the engine and gives more mpg?

[heffay]

Pings too  much with premium? WTF Hef?

well- high grade gas explodes a lot quicker... with a bike that is soooo far advanced in timing already any more advancement tends to make it ping. 

i forget at what rpm but its max advance is somethin like 45 or 48 degrees btdc   

[Einyodeler]

well- high grade gas explodes a lot quicker... with a bike that is soooo far advanced in timing already any more advancement tends to make it ping. 

i forget at what rpm but its max advance is somethin like 45 or 48 degrees btdc   

Because of the fairly low compression ratio I run regular in my SOHC4s.
Hey Hef
Actually the high grade gas burns slower.

 All about gasoline here:

 http://motorcycleinfo.calsci.com/Gasoline.html

[Gordon]

Oh man, someone opened up a can of worms here!   I won't get too into it since I've already quoted most of my research in several past discussions, but I'll condense it here:

The only engines that will benefit from high octane fuel are the ones designed to use it, and the ones with artificially high compression due to excess carbon build-up.  Adding octane to gas allows for higher compression ratios because it prevents the fuel from pre-igniting or pinging, but high octane gas actually has slightly less energy per volume than regular gas does.  If a non high-compression engine runs better on premium, it's time to clean out the combustion chamber. 

Heffay, the reason your Jeep manual calls for 91 octane is because that was going by the old system of octane rating.  Translating to todays system that number would be 87 (regular).  And since we're up here at altitude, 85 is our regular.

[SteveD CB500F]

I won't get too into it since I've already quoted most of my research in several past discussions

Can you point me at these threads Gordon?
I'll write up a FAQ.

[Gordon]

Can you point me at these threads Gordon?
I'll write up a FAQ.

There was one thread in particular that I remember really getting into it, but it was back on the old Greenspun forums.  If those are archived, it may still be around. 

But there's something I've discovered about this topic through discussions in this group and many face-to-face conversations:  Most of the time, if someone has convinced themselves that using premium in their non-premium designed engine makes it run better/faster/stronger/cleaner, no amount of facts or physics will change their mind.  If it makes you feel better, and you have the extra cash to burn, then buy the premium. 

[SteveD CB500F]

I've run a quick search on the archives:

http://www.glennstauffer.com/smf/

but can't find anything specific.

You're right about people though - if it makes you feel that you're getting value for money - then you're getting value for money!

[Harry]

I won't get too into it since I've already quoted most of my research in several past discussions

Can you point me at these threads Gordon?
I'll write up a FAQ.

Gentlemen, I refer you to http://www.sohc4.us/forums/index.php?topic=264.0

[SteveD CB500F]

Hmm.

Hoist by my own (FAQ) petard ??

Gordon - do you concur with what Harry has written in the FAQ?  If so, let's leave it at that and point all newbie questions there.

[Gordon]

Gordon - do you concur with what Harry has written in the FAQ?  If so, let's leave it at that and point all newbie questions there.

I can't argue with the facts!  Thanks Harry. 

[Harry]

(Blushes and clears his throat while looking at his feet)

[Gordon]

Einyodeler had a good link in his post: http://motorcycleinfo.calsci.com/Gasoline.html

And for the purposes of a FAQ, here are a few more.

http://www.edmunds.com/advice/specialreports/articles/106293/article.html

http://www.straightdope.com/columns/041008.html

http://www.epinions.com/content_2346164356

[eldar]

OH OH I got one!! Which side do you fill from? 

[Gordon]

OH OH I got one!! Which side do you fill from? 

The outside, of course!

[cb350twin]

well i sorta go by what the owners manuel says from 1973 says 95 leaded  which of coruse they  make here in the US anymore so i use 93 unleaded with a little bit of lead subitute every once in a while
 Dose that sound good? hehe

[heffay]

soooo... i feel like this entire thread is on here just to prove my stupidity.

but, in my defense... ummm... ok, yeah, i'm in buffo's boat. 

i am going to do some experimenting with grades of gas... although i have been so i thought i was right... but, everything that is being said contradicts.  i will let you know... if there are any findings whatsoever.  it's so hard to tell in a situation like this... you know, things exploding, engines containing those explosions, somethings gotta give and most likely... it won't be pretty!

[Hop on a Honda]

It would be interresting to match the variations gasoline as you call it BUT which fuel actually helps make the CB SOHC run to its maximum capacity.
The Unleaded Fuel in Australia would make a volvo ping! and it seems to have lots of goo in the mix. The SHELLL Optimax seems to have the advantage.

I still say use the best HEIU you can
HEIU =  High Energy Ignition  Unit
Use NGK IRRIDIUM spark plugs.
Dave Australia.

[Gibson]

I use regular since gas cost's so mutch. Annything better cut's into my Beer and project bike money too hard.

[mrbreeze]

Hey Heffay in Colorado,I thought you went to a fancy school for bike mechanics.Where did you hear that high octane gas burnt quicker than low octane gas ?You got your wires crossed dude!!! If you are runnin' an engine (Any engine!) that pings on hi octane fuel,then your ignition timing is too far advanced.Sorry but thats the way it is.