Fuel mix ratio?

Mountainman650 · Post by **Mountainman650** » 08:47 pm May 25 2005

Hey guys
wondering what fuel mix ratio most guys are using??
I'm starting out with a 40:1 mix (93 KDX 250).
Is that pretty standard ?The last 2 smoke I owned was a Banshee
and that thing liked it rich at 32:1 ..........
Thanks
Dave in Pa.

Post by **KDXGarage** » 09:13 pm May 25 2005

That sounds good to me. I am switching from 32:1 to 40:1 when I get back to riding. I have used 32:1 for years with no problems. I am never on the gas for long, so I doubt my bike needs that much lubrication.

John Cena · Post by **John Cena** » 09:57 pm May 25 2005

I use 40:1, I ride in sand no problem and my bike don't smoke

skipro3 · Post by **skipro3** » 10:03 pm May 25 2005

40:1 mainly because it's easy to mix at 1 pint for 5 gallons of gas. Be aware that the mix ratio can affect jetting though. More oil = less gas so the bike will run leaner if you go from 40:1 to 32:1.

dave04kdx · Post by **dave04kdx** » 11:18 pm May 28 2005

Ski:

That avitar is a riot!

skipro3 · Post by **skipro3** » 12:42 am May 29 2005

Thanks Dave. It's hard to read the caption so I added it to my signature line as well. I was on another forum where a post got deleted. When asked why, this photo was up with the caption. I laughed so hard because it reminded me of Okie! Ha!!! So the photo is of Okie and I have indeed, annoyed that monkey!

dave04kdx · Post by **dave04kdx** » 08:10 am May 29 2005

Moutainman650

I also run 40:1, easy to mix, my 04 has not fouled a plug in over 300 hours of use. (after changing factory jetting of course!)

Ski:

This is kind of a thread hijack but I have to say that we have a great forum here.

The quality/quantity of information here is outstanding.

I took a look a the other place (the dark side) yesterday for the first time in months. The questions were the same old &^%$ and the monkeys cronies were spewing out the same old smart arse answers. This place rocks!

skipro3 · Post by **skipro3** » 08:23 pm May 29 2005

I used to run 50:1 thinking that it would cut down on spooge. That was before I knew that spooge is unburned fuel (read: gas and NOT necessarily premix oil). So, for anyone who wasn't aware, I'll say it again; spooge, the goop coming out the tail pipe, is mostly unburned gas. It's important to understand why the fuel isn't burning as there can be several reasons. The main reason is that gas must atomize in order to burn. Micro droplets of gas do not burn. It's too large to work with the oxygen molicule to support combustion.
So don't go messing with the oil/fuel ratio in an effort to cut down on spooge. First, settle on what ratio you are going to be comfortable running, whether it's 32:1, 40:1, 50:1 even 100:1. Then jet the bike to that ratio following the prescribed methods. (For more info on specifice jetting proceedures, check other threads or start a new post)

I wonder about your statement, Mountainman, where you said your Banshee likeed it rich at 32:1. If by rich, you mean it likes more oil than fuel, then o.k. But.....usually rich refers to the fuel portion of the mix; the first #. 32:1 is leaner than 40:1 for example. In the first ratio, there are 32 parts of gas to 1 part oil. IN the second ratio there is 40 parts of gas to 1 part oil. Assume the same amount of mix in both ratios delivered to a motor and you see the second ratio of 40:1 is richer than the first ratio, right? This can all be very confusing. You probably already know all this but I thought I'd try and make it clear to the layman out there reading this for their own application. Hope I didn't make it even muddier than it is!

Daveo4KDX: Yup! This is one cool site!! Credit to Vince for the patience he has with all of us and trusting we will do the right thing here. It is the presumption that we are adults and can moderate our selves that makes the culture here at Woodsrider so much more like family than rivals. There's been times, I'm sure, Vince had good cause to rein in the unruley but by letting the group self moderate by ignoring the potiential for a problem to develop, he's allowed us to develop into a mature group of members. I know some of my posts have been censured by just that method: ignored. It takes great restraint and disipline to show your back to someone who steps over the line and not start out flaming them. Cudos to EVERYONE here!!!!

rlbranson · Post by **rlbranson** » 09:43 am May 30 2005

I think the guy talking about running rich at 32:1 meant rich on oil. Years ago 32;1 was standard, but the oil today is much better and you don't need as much. In fact more oil is not good because more oil reduces the octane of the gas mix. Lower octane is not desirable. I don't think spooge is all gasoline because it would evaporate and it doesn't. My silencer has a drain screw and I sometimes drain spooge out of the silencer after a ride. What drains out is black thick sticky oil that doesn't evaporate. It doesn't even smell like gasoline. The silencer gets hot enough to evaporate gasoline coming through.

Bob
kdx200

Post by **Indawoods** » 10:48 am May 30 2005

Correct... if you have unburned gas...you definately have unburned oil!

But a bike running 32:1 will run higher compression and give more horse.... that's a fact!

clutchcover · Post by **clutchcover** » 12:01 pm May 30 2005

Wouldn't the extra oil help with preignition? Much in the same way lead was used in gas to boost octane? I use 32:1, never foul plugs, my topends last forever, never had a lube related failure, and don't have problems with spooge. Spooge is not gas, but because it is mixed with the gas, it is directly related to the amount of gas the motor is using. Running rich is what causes excess spooge, not the amount of oil. IMO, the extra ring seal that is created by the extra oil is a big plus. Less wear is a good thing. 40:1 is a fine mix, but I like to scream alot, and feel much safer with 32:1. When I have run less oil, and in other bikes I've worked on, there is almost no residual oil buildup in the bottom end. Made me a little weary. I like things nice and oily.

Post by **Indawoods** » 12:14 pm May 30 2005

40:1 in a KDX is usually perfectly fine... we are not out running MX races where the throttle is pinned all the time.

I would be a little weary of anything more though. Oil is what your motor wants and needs.... Like Ski said... 40:1 is an easy mix and seems to work great in a KDX.

Makes things a little less smoky to boot.... but 32:1 is ideal all around.

Mountainman650 · Post by **Mountainman650** » 08:51 pm May 30 2005

Hey skipro3
Yeah, my bad ...
I meant rich,oil wise... sorry for any confusion.
I love reading all the responses, I haven't owned a 2-stroker
in a while so, all the input is great to hear...
Thanks
Dave in Pa.

skipro3 · Post by **skipro3** » 12:18 pm May 31 2005

When I indicated that spooge wasn't necessarily oil but fuel, I don't mean raw gas, but gas exposed to high heat, pressures, mixed with burned hydrocarbons, etc. This "cooked" fuel (gas and oil but remember; 40 parts gas to oil so it is mostly gas) doesn't evaporate like raw fuel might.

mr_munt · Post by **mr_munt** » 12:53 pm May 31 2005

With reference to the spooge, Now correct me if I am wrong. It is my understanding that a 2 stroke lubricates on the none dentenation stroke so half of you fuel is going out the tail pipe any way.. ( thats way the powers to be are trying to due away with 2 strokes.) So your always going to get the spooge build up. So the more oil the better for the longevity of the parts that need lubrication from the mix. Also lead wasn't added to gas to increase octane it was added to soften the blow of the valve against the valve seat.

Colorado Mike · Post by **Colorado Mike** » 01:20 pm May 31 2005

on a two stroke, there is no "non-detonation" stroke. The plug fires every stroke and ignites mixture. That's partly why a two stroke makes so much more power for a given displacement over most four strokes.

canyncarvr · Post by **canyncarvr** » 01:23 pm May 31 2005

re: '..none..' what?

A 2-stroke fires every piston TDC (Top-Dead-Center) event. You're referring to a BDC (Opposite-Of-Top-Dead-Center...Bottom, even) event?

There is oiled fuel below the piston all of the time, so I guess you could say a 2-stroke lubricates itself all over the place.

Skipro wrote:I used to run 50:1 thinking

....etc...

Yessir!

Which is why port jobs can screw you! But...that's another story.

BTW, the Banshee specs call for 24:1 fuel/oil mix. I run mine @ 40:1..in the sand...WOT a lot of the time...huge loads on the engine.

40:1 is fine. If you need an expert rec, Maxima says 40:1 is fine, too.

re: 'we're all adults...'

Gee. If you're going to be nasty to me, just send me an email! No need to go public!!

skipro3 · Post by **skipro3** » 01:52 pm May 31 2005

canyncarvr wrote:re: 'we're all adults...'

Gee. If you're going to be nasty to me, just send me an email! No need to go public!!

I never said we were ALL adults. If I toss out a common garment and you claim it fits, that's your problem!! HaW! HaW! HaW! (Snort!) opps! sorry!

Heck, I didn't even say we were adults. I said that Inda presumes we are. Fooled him didn't we?!

canyncarvr · Post by **canyncarvr** » 04:05 pm May 31 2005

Point taken.

I should'a red it bedder...wordz meening things and all.....

p.s.
Very funny!

mr_munt · Post by **mr_munt** » 06:55 pm May 31 2005

Ok I was wrong about the not firing every stroke I was thing in terms of boat motors with more than one piston. Hey I'm not a mechanic.

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Fuel mix ratio?

Fuel mix ratio?