I've been riding thru spring on 87 octane. Today I gased up and decided to put in 89 since 89 is about 8 cents cheaper per gallon than 87 here in Iowa. I don't understand that logic either. She was running smoothly and idled perfectly around 800 RPMs until this. Now I got to keep the choke on longer to warm her up, weird, and she really wants to idle around 1200-1500 rpms. I could not have imagined that 2 octane rating difference would cause this much trouble.

its the ethanol.  Ethanol has its own oxygen molecule so it needs to run much more rich.  I have thought about putting in 89 because iowa pays you to take it from them and I have noticed the price gap getting bigger and bigger here, but I have not done it for fear of this.  I am glad to learn from your experience that I have been doing the right thing running 87 here.  You should see a dip in gas mileage with ethanol also because it need to run so much more rich.  A fuel injected car (or maybe bike?) will pick up that it is running lean and enrich the fuel mixture, but no carburator will ever run properly with both ethanol watered down gas and real gas.  the octane rating has nothing to do with your experience except that ethanol is hard to burn so it raises the octane.

you gotta keep the farmers happy though 

You should really set your idle to around 1200, 800 rpm seems quite low to me

I'm thinking of draining my tank so my plugs won't get fouled. Lesson learn.

Why set idle to 1200 when it idles perfectly at 800? Wouldn't a lower idle keep the bike cooler too?

Plugs wont get fouled with ethanol. Although the little rubber bits might suffer. That's open to debate and I won't go there.

The idle should be set to ~1200rpm. Why? Some guy with an engineering degree said so 

Quote from: Deros514 on July 01, 2010, 04:40:03 PM
Plugs wont get fouled with ethanol. Although the little rubber bits might suffer. That's open to debate and I won't go there.

The idle should be set to ~1200rpm. Why? Some guy with an engineering degree said so 

Cool. With my pipe setup, 1200 is just too loud. I've been running it at 800 the last 3 years and will keep unless there is a VERY good reason to change.

Here we run on 24% alcohol/gasoline. It work's just fine, only the mileage suffers a little.

Quote from: seamax on July 01, 2010, 04:38:25 PM
I'm thinking of draining my tank so my plugs won't get fouled. Lesson learn.

Why set idle to 1200 when it idles perfectly at 800? Wouldn't a lower idle keep the bike cooler too?

at 800 rpm the oil pump may not be pumping enough oil to properly protect/cool the engine. yes, the oil tranfers the heat and cools the engine. I dont know if its too low for sure, but i wouldn't let it idle below 1000 for long personally.

Quote from: black and silver twin on July 01, 2010, 10:02:02 PM

Quote from: seamax on July 01, 2010, 04:38:25 PM
I'm thinking of draining my tank so my plugs won't get fouled. Lesson learn.

Why set idle to 1200 when it idles perfectly at 800? Wouldn't a lower idle keep the bike cooler too?

at 800 rpm the oil pump may not be pumping enough oil to properly protect/cool the engine. yes, the oil tranfers the heat and cools the engine. I dont know if its too low for sure, but i wouldn't let it idle below 1000 for long personally.

Wouldn't oil cooling require a small oil radiator like on some old suzukis?

Yes 1200 minimum for the idle rpm, I even set em as high as 1500 if its used as a commuter in a lot of traffic. RPM = oil pressure. Cars that idle a lot, like taxi cabs eat camshafts. First spot you'd see wear if it was idled that low.
Cool.
Buddha.

Quote from: seamax on July 02, 2010, 07:50:08 AM

Quote from: black and silver twin on July 01, 2010, 10:02:02 PM

Quote from: seamax on July 01, 2010, 04:38:25 PM
I'm thinking of draining my tank so my plugs won't get fouled. Lesson learn.

Why set idle to 1200 when it idles perfectly at 800? Wouldn't a lower idle keep the bike cooler too?

at 800 rpm the oil pump may not be pumping enough oil to properly protect/cool the engine. yes, the oil tranfers the heat and cools the engine. I dont know if its too low for sure, but i wouldn't let it idle below 1000 for long personally.

Wouldn't oil cooling require a small oil radiator like on some old suzukis?

the oil is pumped up through the engine then travels down through return passages to the oil pan. the passages are near the edge of the block running vertically. on its way up the oil gets hot, then on its way down it transfers the heat to the cooling fins, which is then dissipated into the air around the engine.

Also new suzukis have oil coolers, my 07 gs500f does, sv650/1000 has oil and water cooling, all katanas were oil cooled, ect. but just because it doesnt have an oil cooler doesnt mean the oil doesnt transfer heat, air cooled motors are cooled by the oil pumping through them. 

Was it a pump with one hose, or multiple hoses? I try to put 91 in newer bikes, but I always figure I'm probably getting screwed at pumps with 1 hose when i only ever buy 2 gallons at a time. Most people with cars but 87, and when I pick 91 I probably get a gallon or more of the left over 87 that's already in the hose, and would be surprised if I even got enough 91 to make it worth it, even though I'm paying for it.

My xb9 doesn't even idle at 800, and the stroke on that bike is long enough that the redline is only 7200. I would even turn the idle up on my GS a little if it wouldn't get a hanging idle.

Will adjust the idle this week to see how she acts. Most pumps these days are one hose and you choose the octane with the button. In Iowa, 89 octane is the cheapest, then 87 and 91.

Quote from: seamax on July 01, 2010, 02:05:21 PM
I've been riding thru spring on 87 octane. Today I gased up and decided to put in 89 since 89 is about 8 cents cheaper per gallon than 87 here in Iowa. I don't understand that logic either. She was running smoothly and idled perfectly around 800 RPMs until this. Now I got to keep the choke on longer to warm her up, weird, and she really wants to idle around 1200-1500 rpms. I could not have imagined that 2 octane rating difference would cause this much trouble.

Besides changing the Octane, is the Brand of gas the same?

I noticed worse idling/warm-up in winter with Shell gas vs BP gas which has no issues.

Michael

Haven't really notice Brand change, only octane.

Anyways I took everybody's advice and set the idle to around 1300. I took the bike for a 200 mile total ride over the weekend and here is what I notice. Warmup is of course much shorter but the MAJOR difference was in how smooth the shifting was especially in stop and go traffic. I was able to find neutral everytime. Before during long rides the shifting was very notchy. Sometimes in stop and go traffic I would have to use excessive force to shift and it was so hard to get it into neutral. I just thought this was normal with an older engine and hot temps. Learn something new here all the time.

Pic of her washed down after the long ride.