Author Topic: yeah, yeah. another octane thread... (Read 6561 times)

land_shark · « **on:** May 10, 2005, 01:22:48 PM »

I've been running with premium(~92) octane for years, and decided to give the non-oxegenated 87 a shot. I'll be damned if it doesn't run smoother, it's more responsive, warms up faster, doesn't surge, and gets better gas mileage.

I have a Yosh pipe with stock jetting, fyi.

I know this is a topic that's been beaten beyond reason. I feel like the kid in class that just woke up and started to listen.

dsartwell1 · « **Reply #1 on:** May 10, 2005, 05:58:24 PM »

I'm with you on that. I just started using 87 after reading about it. Does seem to run better. I didn't notice a big change but even no change means I was wasting money.

WEINERDOGBONE · « **Reply #2 on:** May 10, 2005, 06:36:32 PM »

I loaned my B12 to a friend over the weekend and it brought it back filled with premium fuel. It ran like crap. He figured I used premium fuel because of my mods.

It doesn't idle for crap. It seemed like it made the bike run overly rich. Not good man.

Red01 · « **Reply #3 on:** May 10, 2005, 08:02:21 PM »

It's not running any richer, it just feels sluggish in comparison because the higher octane fuel is harder to ignite.

WEINERDOGBONE · « **Reply #4 on:** May 10, 2005, 10:20:33 PM »

I see. Do you suppose that would have fouled my plug in the # 1 cylinder? I never had that problem before.

Red01 · « **Reply #5 on:** May 10, 2005, 11:48:55 PM »

Possibly, though I would doubt it would only foul one plug. Might look for other causes.

deanz12 · « **Reply #6 on:** May 17, 2005, 08:05:50 PM »

Oxygenated fuel has alchol in it. About 10% I think. That means you are running 10% leaner when your using it. The local alki burners at the drag strip say to double the jet sizes to run alchol.

Red01 · « **Reply #7 on:** May 18, 2005, 05:14:19 AM »

I know the CA bikes have different jets than the 49 state bikes - perhaps to compensate for their oxygenated fuel? However, I haven't heard of CA riders having to jet any richer than anyone else.

We used to get oxygenated fuel in the winter here, but don't anymore... and I'm glad! Get more power and economy out of plain unleaded.

deanz12 · « **Reply #8 on:** May 19, 2005, 04:39:33 AM »

California B12's have different jets? What size do they run?

Red01 · « **Reply #9 on:** May 19, 2005, 09:11:47 PM »

I don't know exactly what size the CA bikes run, but they have different needles, needle jets, and mains than 49-state bikes. The numbers are similar, but have suffixes the others don't have. I can't seem to find the exact info right now, but here's a some of it on the 1G:

1G Carburetor Specifications
US, European, Canadian, and Australian 1200cc models:
(California models in parenthesis)

Carb type: Mikuni BST36SS
Main Jet: 102.5
Jet Needle: 5D76-4th (5D80 - CA)
Needle Jet: O-8 (0-8M - CA)
Throttle Valve: #120
Pilot Jet: #37.5
Pilot Screw: PRESET (1-3/4 turns)

deanz12 · « **Reply #10 on:** May 20, 2005, 02:47:37 PM »

I didn't know that. Still, for us B12 guys 10% is ( assuming a stock 100 main jet) a 110 main. Quite a difference.

B6mick · « **Reply #11 on:** May 21, 2005, 08:44:26 AM »

Gee if I run (because premium is unavailable) regular unleaded the poor little B6 pings its little brains out,and generally objects to it, no end. I can get away with a half/half mix, but I have to be carefull at low RPM's I can not hit the gas hard without pinging. yet with premium I have zero pinging, a healthy idle, and an engine thet will pull evenly and cleanly through the whole rev range. Plugs last without fouling for 30thousand K's which is about 18thousand miles. So I can only assume that its all down to the state of tune.

Dragbike · « **Reply #12 on:** May 21, 2005, 12:03:51 PM »

Hello!
Ok, this is more than anyone would need to know,, (But if it is raining out),, some good reading. :blahblah:
http://www.faqs.org/faqs/autos/gasoline-faq/part1/
Brent

aussiebandit · « **Reply #13 on:** May 22, 2005, 06:40:14 AM »

I've found no real difference in the performance of the B12 between 'standard' and 'premium', except for Shell Optimax which made the bike a pig to start in Winter.

The treasurer on the other hand has found that her M750 runs sooooo much better on premium that she now runs this all time, unless there is no other option. Oh and the M750 doesn't like the Optimax stuff either.

Slider · « **Reply #14 on:** May 26, 2005, 01:55:54 AM »

Quote from: "land_shark"

I've been running with premium(~92) octane for years, and decided to give the non-oxegenated 87 a shot. I'll be damned if it doesn't run smoother, it's more responsive, warms up faster, doesn't surge, and gets better gas mileage. I have a Yosh pipe with stock jetting, fyi.

I know this is a topic that's been beaten beyond reason. I feel like the kid in class that just woke up and started to listen.

I have been running 87 Octane with a Yosh can too. For me, it seems to be a wash. I can't tell the diff. I did have troubles with low Octance on a really hot day before I had a jet job, though.

I was having trouble with low speed roughness and stumble. The local dealer said I needed to order a jet kit = $275 Canadian. More $ to put it in and troubleshoot. I got the feeling he had never done one on a Bandit. I went to a larger dealer in a town nearby and he scoffed at the Jet kit idea. He said the Yoshi slip on and KNN filter, stock cams, airbox etc. didn’t need the kit. He said he would be giving me 90% of the parts back in my hand. I asked him if he had done these before and he said ‘at least ten’. What he suggested and did was:
-drilled the low speed jet covers out and adjusted the low speed settings richer.
-raise the main needles a notch or two
Drivability is now from 1-1.5k to 10k+ rpm. I’m sure the full throttle setting is a tad rich but you can’t keep your license for long if you use very much. Low speed mileage does not seem to suffer.