speaking of fuel...

I have an 82 750 maxim. What octane do you all use? I have always used the 87 octane "cheap" (ha!) stuff. Is that ok or should I burn something better. Thanks, flash

 

I just use 87 myself. When these bikes were made, if you read in the service manual, It recommends Regular. Now we're just dating our Bikes (LOL)

 

myself use at least 93 in every gas powered machine i own. my cars, outboard, bike, lawnmower, ect

i know most people say its a waste but i know it increases milage and has made my 2000 4 banger car that i bought new in 2000 now has 150000 miles. and nothing wrong with motor.

so anyways i use 93 and love it

 

I use whatever the recommended octane is. In my 2001 Ranger with the 3.0 v6 I get 20 overall and 25 highway with 87. If I use 93 the mileage drops to 17 overall and 21 highway. You should use the lowest octane rating that does not cause any pinging or spark knock.If you use a higher octane than needed it can reduce fuel mileage and cause excess carbon build up in the cylinders over time wich can cause pinging, detonation and other driveability issues.
My two cents worth.

James

Edit: These mpg numbers are not one tank numbers, they are an average of ten consectutive fillups from the same gas station and the same pump. Fuel tank is 20 gallons with an average fill of 15 gallons.

 

Cheapest!

Holla at the poor peeps in da house!

 

i use premium fuel, and am very picky where i fill. I dont use Mohawk or Husky since they add ethanol. I hate ETHANOL!

 

With the possible exception of the 1980 year, all XJ engines were designed for unleaded fuel -- no matter what the manual that came with it says (they reused old manuals).

The engines were designed for the standard 87 octane fuel -- the extra octane in mid- or premium fuel isn't doing squat for you. Well, except draining your wallet faster. Remember - octane is an ignition SUPPRESSANT, makes it slightly harder to ignite (high compression, etc)

Flip-side of that coin is that the different additive package in the premium fuel MIGHT offer some benefit -- but to be honest, I can't imagine what that would be.

Unless you're getting "pinging" (pre-ignition), you don't need anything more than 87.

 

My bike was "Pinging" something wicked last Summer. I bumped-up to High-test and the Ping went away.

You should know that there was double-digit percent Ethanol in the Regular.

 

I HATE ETHANOL!!!
I do however use a blend of ethanol in my 06 Camry as it is designed for it. These bikes were never designed for ethanol and the rubber in our carbs which is hard to come by gets ate up by it!

I use 87 octane and never have had any pinging.

If you prefer higher octane that's your right, but I can't afford it!!
Oil companies and refinerys are raping us bad enough!!!

 

I think mine runs better on high octane since the head has been shaved.
And i have a sparkplug problem, not sure how much they shaved, but more than enough.

 

Octane also acts as an antiknock agent... ran my WRX on 89 (ONCE), and it could tell.

I remember reading somewhere that the higher octane can increase operating temperatures, which would not be good for an air cooled engine. Is there any truth to that?

 

Octane requirement is established by ignition timing and compression ratio.
Rule of thumb is 10:1 and higher, high test (91RON or better). Advanced ignition needs it too. Given our verable old beasts are running 9.2 to 1 (Haynes numbers) at anywhere from 7 to 10 degrees BTDC, 87 octane should be just fine. Change any of the variables (i.e. advance timing, shave head, use higher compression pistons) and you need to address the octane needs of the engine.
Bottom line, what ever your beast likes that doesn't make it ping is the right octane.

 

Thanks for all the info. It runs fine at 87 so that's where we'll stay! Flash