Gas Type?

[greencow]

When i went ridding not to long ago i was about to fill up on 87 and my friend yelled at me saying that im going to rune my carb then my other frends dad was saying how i was going to lag behind if i was to put 87 in (ya right) and so then i switched to 91 not knowing why or how i was going to fall behind or how its going to kill my carb. I would like to know the difference between 87,89,91 i know it has something to do with the burn time. The cost really does not matter its still only like 8$ to fill up on 91. I know with cars theres a recommended gas type. Is it the same for 400 ex?


Thanks

[2001400exrida]

wow, hey man the search button is your friend, this has been beat to death.

you can run 87 on stock compression.

i run 93 in all my machines. one is stock and one is 11:1 high comp. they both run great on 93.

[greencow]

I would love to look at a thread about this but you cant search gas. I search about every topic before i post a new thread


"The search term you specified (gas) is under the minimum word length (4)"

[2001400exrida]

search gas* (with the asterix) or search "fuel" or "octane" or "gasoline". you have several options brother.

[greencow]

Thanks for the help

[AtvKid4Eva]

on my stock motor 87 is fine. thats all i ran when i had my 400 and never had a problem. 89 would be alright too 93 would be overkill.

[2001400exrida]

the manual says 92 min.

I stick with 91 or 93 to be on the safe side.

I won't go any lower than the recommended octane.

I have buddies who run 87 all the time with no problems at all. I just like the peace of mind that i know i'm running my quad to spec :)

[BenHonda400ex]

Why do you guys worry so much about your gas? I mean I kinda understand this but why worry? It's pretty much all the same until you get to special racing gas like VP.. I put anything my brother puts in his truck

[2001400exrida]

well if it's pinging you need to worry about it, and both of mine ping with 87 octane. maybe i got a bad batch but they run better with 93 or mixed 87/110.

[Rkangel7]

Octane is the rating of gasoline's resistance to detonation (knocking). The higher the octane the more resistant to detonation. Detonation is when the heat of compression causes gasoline to spontaneously ignite at the wrong time, rather than being ignited at the right time by the spark plug. Detonation can cause damage.

Lower octane does not decrease horsepower. Higher octane does not increase horsepower. Octane ratings will not kill your carb or cause you to fall behind. Higher octane will allow higher compression ratios (which can increase horsepower) or allow for higher temperatures (such as warm weather or high RPM riding). Since the 400ex is only air/oil cooled, my rule of thumb has always been that octane is your friend. For this reason I always run 91 or better.

[2001400exrida]

x2 on that rk

also, you can't possibly say that 93 is overkill, when the manual suggests 92 minimum.

obviously 110 would be overkill but not 93, that's right about what is recommended by honda.

[BenHonda400ex]

Originally posted by 2001400exrida
x2 on that rk

also, you can't possibly say that 93 is overkill, when the manual suggests 92 minimum.

obviously 110 would be overkill but not 93, that's right about what is recommended by honda. Not trying to smart off or anything.. But don't some race bikes race with 110?

[2001400exrida]

i thought we were talking about mostly stock motors.

yes race motors will run 110 and for them with a high comp piston it won't be overkill but for most lightly modded 400ex's. Pretty much Anything up to 11:1 can run 93 octane. when you get to 12:1 and 13:1 u may require 110 octane.

[fearlessfred]

Originally posted by Rkangel7
Octane is the rating of gasoline's resistance to detonation (knocking). The higher the octane the more resistant to detonation. Detonation is when the heat of compression causes gasoline to spontaneously ignite at the wrong time, rather than being ignited at the right time by the spark plug. Detonation can cause damage.

Lower octane does not decrease horsepower. Higher octane does not increase horsepower. Octane ratings will not kill your carb or cause you to fall behind. Higher octane will allow higher compression ratios (which can increase horsepower) or allow for higher temperatures (such as warm weather or high RPM riding). Since the 400ex is only air/oil cooled, my rule of thumb has always been that octane is your friend. For this reason I always run 91 or better. great answer

[hocman123]

the 87 gas also can't sit for vary long before going bad. I had a friend who ran 87 and his was in his garage for 2 months and would not start. We check everthing and edventually we poored less then a gallen on 92 and a cap full of sea foam carb clearner. we each got on a peg rocked it really good and it started up after a few more cranks. he never runs lees then 92 now exspecially since he goes away for work all the time for 2 months at a time.

[greencow]

Originally posted by Rkangel7
Octane is the rating of gasoline's resistance to detonation (knocking). The higher the octane the more resistant to detonation. Detonation is when the heat of compression causes gasoline to spontaneously ignite at the wrong time, rather than being ignited at the right time by the spark plug. Detonation can cause damage.

Lower octane does not decrease horsepower. Higher octane does not increase horsepower. Octane ratings will not kill your carb or cause you to fall behind. Higher octane will allow higher compression ratios (which can increase horsepower) or allow for higher temperatures (such as warm weather or high RPM riding). Since the 400ex is only air/oil cooled, my rule of thumb has always been that octane is your friend. For this reason I always run 91 or better.

So the 87 octane rating will not hurt my carb at all i will not have to clean it more or anything right?
I started running 91 from now on but what got me was my friends and the carb haha.

Thanks alot

[99400esex]

run 93 in it

[CJM]

Originally posted by greencow
So the 87 octane rating will not hurt my carb at all i will not have to clean it more or anything right?
I started running 91 from now on but what got me was my friends and the carb haha.

Thanks alot

Problem is that despite what people thing, 87 or 85 or whatever lower octane has more ethanol in it. I dont trust that they say its the same..its not. More ethanol more it absorbs water in the gas..very bad.

Like Hocman said, 87 due to having more ethanol than higher octanes tends to absorb water way to easily. I tried to use some 3 months old in my lawnmower and it ran like crap. The lawnmower shop I frequent, all the landscapers I know, my buddies who ride and my quad mechanics all say to never run less than 91 octane.

[fearlessfred]

[QUOTE]Originally posted by CJM
Problem is that despite what people thing, 87 or 85 or whatever lower octane has more ethanol in it. I dont trust that they say its the same..its not. More ethanol more it absorbs water in the gas..very bad.

Like Hocman said, 87 due to having more ethanol than higher octanes tends to absorb water way to easily. I tried to use some 3 months old in my lawnmower and it ran like crap. The lawnmower shop I frequent, all the landscapers I know, my buddies who ride and my quad mechanics all say to never run less than 91 octane. [/ i am not disagreeing with your statement, but i have never heard that lower octane fuel has more ethanol . i always run 93 in my bikes, so i guess i never payed much attention

[CJM]

I never believed it either, not till I went to use that gas and my buddy hocmans friend had the same issue.

Both were 87 octane and both sat for a few months. To compare I have had the same gas in my EX for probably 3 months since Ive ridden, was 93 octane-bike kicked right over. Started a friends yfz today too, he uses 93 and no issues.

[Rkangel7]

Ethanol is often used because of environmental mandates, and probably because it's cheaper than other octane boosting additives.

Unfortunately, my state now requires all gasoline to be at least 10% Ethanol, so there is no getting away from it. As a result we have gotten into the habit of rotating our gas often and cleaning the carbs at the beginning of the riding season. It sucks but it happens even with 93 octane here.

[fearlessfred]

Originally posted by Rkangel7
Ethanol is often used because of environmental mandates, and probably because it's cheaper than other octane boosting additives.

Unfortunately, my state now requires all gasoline to be at least 10% Ethanol, so there is no getting away from it. As a result we have gotten into the habit of rotating our gas often and cleaning the carbs at the beginning of the riding season. It sucks but it happens even with 93 octane here. yea here in vegas we have 10 percent in the winter months but i think the lack of moister in the desert, prob. helps i beleive it is the water that is the prob

[CJM]

I also find in the warmer months here the gas does store better. I wonder if moisture in the air plays a role? I also only fill up my quad at the pump, never from a can and I know the tanks sealed pretty tight.

[2001400exrida]

why not fill up from a can? i have a 5 gal. that i just keep mostly full of 110/89 mix.

[CJM]

Originally posted by 2001400exrida
why not fill up from a can? i have a 5 gal. that i just keep mostly full of 110/89 mix.

Cans are vented and leak and allow moisture in.

[2001400exrida]

yeah, my can is not vented, in fact it will expand with pressure when i leave it in the sun so sometimes i will leave the cap unscrewed just a little so it doesn't expand.

gas doesn't go bad as quick as some think it does. also, u have to keep in mind that the 400ex gas tank is not sealed either, so whatever is sitting in your tank is just like what's sitting in the gas can.

gas cans are fine to fill from, i understand that some people may be a little overkill as far as "only filling from the pump". that makes little to no difference, but if it gives you peace of mind then go for it!

[CJM]

I think the EX tank is better sealed than most of the gas cans around today.

Even the ones that arent vented and expand like a swollen wood tick have vents.

maybe its all in my head, IDK. Like I said i dont use cans cause the gas station is on the way to my riding spot so I just fill there.

[2001400exrida]

yeah that's convenient for you. since i have to mix my octanes i'm kinda forced to use the can.

mine can't be vented if it holds that kind of pressure though can it? the 400ex is definetly vented on the cap where the tube comes out. the 400ex should not ever swell up or gain pressure, it's because of that hose that runs out of the cap. it's still sealed yes, but it let's the pressure out before it builds up.

my can has a valve on the nozzle that allows me to open the flow, there's rubber seals in between the cap and the valve so it's pretty darn sealed.

[CJM]

The cans that swell up like that are the newer junk ones, they are BARELY vented. Inside if you look at the nozzle (there are 2 types floating around) is a small vent tube-some have a small vent hole you can unscrew on the back.

Newer cans are supposed to vent using some stupid valve system (the kinda can you push down the lever to make work), but it barely vents anything-thats why it swells up so badly.

If I do use cans I try to only use military scepter cans that use a screw on cap with a chemical resistant clear hose. But you cant buy anymore sadly. If I dont use them I have several much older cans with the spout that pulls out of the can with the old style pull off vent tab, stupid carb laws..

Im just lucky the gas station is right on the way and 93 pump there is very good gas (its a wawa). I have not found anywhere short of going to the local drag track or a town a half hour or more from me selling 100+ octane.