Mixing ratio?

[redrider250f]

Is 32:1 or 36:1 richer? Bear with my stupid questions, i am new to 2 strokes. and what do you suggest for my 02 CR 125, trail riding, and field running and some track(nothing major).

Thanks

[gunner150]

36:1 is richer.

I always ran 32:1.

[redrider250f]

so then 40:1 is richer yet. Correct me if i am wrong, cuz i thought that it was the other way around. I thought that 32:1 meant 32 times as much gas as oil. So wouldn't 36:1 be leaner with 36 times as much gas as oil. Not trying to say your wrong just trying to understand this.

[qwik-E-02CR]

juss think of it this way... 32:1 is 32 drops of gas to 1 drop of oil... 40:1 is 40 drop of gas to 1 drop of oil..the higher the ratio, the leaner it is cuz its less oil compared to the amount of gas..

[SoCalrider21]

Well I just think of the numbers as a percent. If it is 32:1, I just think that 32% of it is oil. So then 40:1 would be 40% oil. ?

[redrider250f]

Alright that helps me alot, thanks.

[qwik-E-02CR]

o and to answer your question above...i would suggest to go with 40:1...i had a 00 cr125 that i sold a little bit ago, and i used 40:1 with maxima castor 927 oil.. I did all hill climbs and trails, and a couple few putt putt laps on the track, but it seemed to work perfect for anything, any altitude. Juss my input

[ravenhawke]

ummm whoever said that 32:1 means it is 32% is soooo wrong. 40:1 is LEANER

[DTHCoCo]

"32:1 rich" "40:1 lean" lol not hard more parts gas the leaner it gets lol 40parts gas to 1 part oil obviously the more parts gas the leaner it gets, 125 use max 40:1.

[SilverSurfer]

32:1 is 32 parts gas, 1 part oil.

40:1 is 40 parts gas, 1 part oil.

Your bike would not run if the ratios were reversed ?

That means 32:1 is richer than 40:1. I run 40:1, personally.

Think of it this way.

32:1 is about 20oz of oil for 5 gallons (640oz) of gas. (20/640=32)

40:1 is about 16oz of oil for 5 gallons (640oz) of gas. (16/640=40)

Pretty simple math, really ?

[CRFan1]

Correct me if I am wrong but the more parts gas in the mixture (and the less oil), the RICHER the FUEL mixture. that is, at 40:1, you AF ratio will be richer than 32:1. 32:1 woul have more parts oil and less parts gas in the mixture and therefore you would have a LEANER AF ratio......

Just go 32:1 like the manula says and ride the snot out of it!!

[CharlieT]

You are all wrong!!!!

The terms rich/lean when used regarding an engine should only be used to desrcribe the air/fuel ratio. Using those terms to describe pre-mix ratios of 2-cycle engines just confuses the hell out of newbies and amatuer tuners. When you run a pre-mix ratio of 32:1 you are simply running a higher premix ratio than 40:1. If you want to make an engine run richer or leaner, you change the jets, not the pre-mix. ??

[Bultaco206]

You are all wrong!!!!

The terms rich/lean when used regarding an engine should only be used to desrcribe the air/fuel ratio. Using those terms to describe pre-mix ratios of 2-cycle engines just confuses the hell out of newbies and amatuer tuners. When you run a pre-mix ratio of 32:1 you are simply running a higher premix ratio than 40:1. If you want to make an engine run richer or leaner, you change the jets, not the pre-mix. ??

We have a winner.

Here's something else to add to the mix (pun intended)...

More gas in the ratio runs cooler.

[CRFan1]

We have a winner.

Here's something else to add to the mix (pun intended)...

More gas in the ratio runs cooler.

Right....cause it's a slightly richer AF mixture, hehe ?

Yes, you do NOT use the pre-mix ratio to tune the bike....jetting does that but if you are on the edge of lean already and you decide to go from say 40:1 to 32:1 pre-mix ratio, you can make an already lean problem worse....but that's not the premix's fault, that's your fault for not jetting correctly in the first place ?

[Baron Von Beard]

Wow! This subject can really confuse a dude if he don't know what he don't know 2 smokes. Listen to CharlieT, he's go it.

BTW - I would not suggest running 32:1. It is more oil than you need and will serve no purpose other than to gunk up your exhaust port, power valve and silencer.

I always ran mine at either 50:1 with Amsoil Dominator or 40:1 if I had to use anything else.

[CharlieT]

CRFan1....you are right about making minor adjustments by altering the pre-mix ratio. If you are trying to get it jetted and you find that ideally you need to "jet" to a non-existent jet, a point between two available jets, you can try and fine tune it by altering the premix ratio. IMHO, however, this is something left to skilled and expereinced tuners, not your average weekend rider.

[CharlieT]

BW, as for mixing ratio....all depends. What displacement engine, what tytpe of use, what rpm range, etc. A big factor, IMHO, is piston speed. Smaller displacment engiens tend to run at a higher rmp range and there fore have a higher avg piston speed. A trials bike or and enduro bike typically run at a much loer rpm rang than a flattracker or a GP bike and hence also have a lower pisoton speed. How tight of a clearance are you running, too. Water or air-cooled? lots of questions.

32:1 is going to be a save overall avg mix ration for most 2/ dirtbikes. A 250 can gt away with a higher ratio better than a 125...again back to piston speed. A 250 trials bike or an enduro bike running at a lower avg rpm range can get away with a higher ration than a 250 miler, again piston speed. The ratio I run in a 250 woods bike vrs say when we road race at a place like Road America, where we are flat out a lot and are consitently running in the 11-13k rpm range with a 125 is not going to be the same. I might run the 250 woods bike at 32:1, but that road racer with 1.2 thou clearence, I'll run at around 18:1....and when properly jetted, it won't foul anything either!!

If you are running a CR125 with 1.2thou clearance vrs one running 2.5thou, you might want a bit more oil.

[Ret09]

Whew! Enough here to confuse even someone that knows about jetting and mixing fuel. He wanted to know what was richer, going up or down with your ratio.

Up means leaner.

Down means richer.

32: 1 is a good ratio to start with.

Some oil recommend a higher ratio like 40:1 or 50:1. That is the manufacturer recommended ratio. You seize your engine though and its on you.

In the 70's a lot of us ran Castor oil (bean oil) at 20:1. The bikes ran great, smoked like chimneys. EPA wasn't concerned back then. Then in the 70's desert guys went to oil like Penzoil and ran 32:1. Worked great for long haul speed runs across deserts and Baja lakes.

In the 80s some oils like High Point recommended 40:1. Some guys went to that and others stayed with 32:1.

Jetting is everything here. Lean out your jetting too much, it wont matter what ratio you run.

Too much oil and slow speeds results in plugs fouling or worse.

Too little oil and you can size up or hole your piston/ break rings.

Go up above 100 octane and you need to re jet for cooler fuel temps. ( A whole different subject here)

I have run 32:1 in a vast majority of 2 stroke dirt bikes since 1975. Huskys, Ossas, Yamahas, Hondas and Bultacos. Works great! ?

[DPR250R]

Run AMSOIL Dominator @ 50:1 and be done with it.

[BigDeSto53]

You are all wrong!!!!

The terms rich/lean when used regarding an engine should only be used to desrcribe the air/fuel ratio. Using those terms to describe pre-mix ratios of 2-cycle engines just confuses the hell out of newbies and amatuer tuners. When you run a pre-mix ratio of 32:1 you are simply running a higher premix ratio than 40:1. If you want to make an engine run richer or leaner, you change the jets, not the pre-mix. ??

Thank GOD someone knows whats up!!!!

Jets! JETS!!! and JETS to lean or richen your bikes!!! NOT PREMIX OIL