85/86 250R oil mix ratio 20:1 or are you running something different?

[dbtiger]

I just picked up an 85 250R a few days ago. Previous owner said he was running 32:1 but I know the service manual calls for 20:1. What ratio are you running, and is there a rule of thumb if you deviate from 20:1.

[fabiodriven]

20:1 was for the oil available at the time your ATC was produced. You can still run that ratio with beanol or straight 30 weight oil, but modern two stroke oils are far superior and you mix it at a much lower ratio of oil. Some are 32:1, some 40:1, some 50:1. I run one bottle of Golden Spectro to five gallons of gas and that's all I've done since the 80's.

I rode with a guy last year (Sanchez) who was running 20:1 beanol. It stunk terribly and nobody could ride behind him.

[RoscoW]

Oil technology has come a long way in the last 30 years, most people run in the 32:1 to 50:1 range with a good quality modern oil. I personally run 50:1 Amsoil and have never had oil related issues. I always have a nice little pool of residual oil sitting in the crankcase upon teardown, and it's an easy mix for long trail rides if you have to get gas, I carry a 1 gal gas can with me and always have a couple little Stihl chainsaw oil bottles with me full of oil to mix at the gas station.

Ross..

[dbtiger]

20:1 was for the oil available at the time your ATC was produced. You can still run that ratio with beanol or straight 30 weight oil, but modern two stroke oils are far superior and you mix it at a much lower ratio of oil. Some are 32:1, some 40:1, some 50:1. I run one bottle of Golden Spectro to five gallons of gas and that's all I've done since the 80's.

I rode with a guy last year (Sanchez) who was running 20:1 beanol. It stunk terribly and nobody could ride behind him.

That’s good to hear. What are the brands with the best reputation? I can get the Lucas Oil semi-synthetic close to the house.

[dbtiger]

Oil technology has come a long way in the last 30 years, most people run in the 32:1 to 50:1 range with a good quality modern oil. I personally run 50:1 Amsoil and have never had oil related issues. I always have a nice little pool of residual oil sitting in the crankcase upon teardown, and it's an easy mix for long trail rides if you have to get gas, I carry a 1 gal gas can with me and always have a couple little Stihl chainsaw oil bottles with me full of oil to mix at the gas station.

Ross..

I like your idea using the small stihl bottles. I always have those lying around the garage.

[fabiodriven]

It's difficult to go wrong with Lucas anything.

[greenhaze20]

I stay with 20:1 and use royal purple. More oil more protection and your motor will last longer. You could use less and probably be fine. I also have a blue cloud of smoke every time I get on it. Would be nice to hear from other guys that run less oil if they still get smoke at WOT.



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[fabiodriven]

I stay with 20:1 and use royal purple. More oil more protection and your motor will last longer. You could use less and probably be fine. I also have a blue cloud of smoke every time I get on it. Would be nice to hear from other guys that run less oil if they still get smoke at WOT.

You're not really getting "more protection", you're just wasting oil and making smoke.

[Doug8765]

You're not really getting "more protection", you're just wasting oil and making smoke.

I had my engine builder tell me 20:1 i said why.. he said do you dyno these motors and then measure the piston / rings i said no. Then use 20:1


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[greenhaze20]

You're not really getting "more protection", you're just wasting oil and making smoke.

So less oil means more protection. Got it.


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[fabiodriven]

So less oil means more protection. Got it.


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No Einstein. Fuel cools, oil lubes. If you take away more fuel your engine could potentially run hotter, and heat is the enemy. But what do I know?

Run whatever you choose, it's your bike. Like I said from the beginning, you CAN run 20:1. What you and this other guy are not taking into account is that modern oils are not intended to run at 20:1. Sure they can, but you're sacrificing your own performance for a gain that very well might be overcome by the higher temperatures you might be making. If you want to spend your money on oil that you don't need to while simultaneously making your bike burble and smoke obnoxiously, and also plugging up your exhaust, go for it.

The entire point of modern oils is to burn as cleanly and efficiently as possible while offering you the best performance you can have. I've had two strokes last years and years and years, I don't think there's any longevity problems with using modern oils the way they've been intended.

[Arky-X]

I had my engine builder tell me 20:1 i said why.. he said do you dyno these motors and then measure the piston / rings i said no. Then use 20:1


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What oil is being used?
SAE 30W?
10W-30?
or some other old school oil?.......if so, then yes, run 20:1

[atc300r]

I run my 3 250rs and 300r on 32:1. with Amsoil dominator mixed with 91 non ethol gas.Amsoil,and some of the popular oils for 2 strokes have been around since the 70s.Klotz has been around for about 60 years.If you are using 86 octane gas with ethol go with 20:1.My local Honda Dealers back in the day recommended Castrol oil .Back in the 80s 2 of my uncles ran their 250rs on 84:1 with Amsoil they used the type that could be mixed at 100:1.They never had any issues and we rode every weekend.

[yaegerb]

I had my engine builder tell me 20:1 i said why.. he said do you dyno these motors and then measure the piston / rings i said no. Then use 20:1


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Get a new engine builder

[yaegerb]

What oil is being used?
SAE 30W?
10W-30?
or some other old school oil?.......if so, then yes, run 20:1

This doesn’t even make sense. When did we change the subject to 4 stroke oil?