Pre mix advice

[supermotodaz]

Finally got to the point of now being able to fire up the 450 , what oil ratio should I ideally be using, it's a 72 wr that will be used purely for motocross, would my 250 wr of similar age also be the same ratio.
Cheer,s
Daz

 

[Kartwheel68]

Man, this is like asking what religion is the best. I wont tell you what you should use, but I will tell you what I use. I use, and have used since about '81, Maxima Castor 927 mixed at 32:1 in everything from my '72 Penton 100 to my '96 Honda CR500. There is no better oil for an air cooled two stroke than a castor based oil, even 100% synthetics can not match the high heat handling capabilities of castor.

 

[Chaz955i]

Man, this is like asking what religion is the best. I wont tell you what you should use, but I will tell you what I use. I use, and have used since about '81, Maxima Castor 927 mixed at 32:1 in everything from my '72 Penton 100 to my '96 Honda CR500. There is no better oil for an air cooled two stroke than a castor based oil, even 100% synthetics can not match the high heat handling capabilities of castor.

This is more specific to the 125/ 175 but do you run race gas or just high test? I've read a few things indicating current gas isn't quite as good as the stuff from 30 years ago but I'd be interested in what you have to say since you clearly have extensive real-world experience with these bikes.

Thanks,
Chuck

 

[grouty]

Same as Kartwheel68, I won't tell you what to use.
I have been using 40:1 for years. I have always used Silkolene Comp 2. Fuel wise I mix 114 octane leaded race fuel at 20% with Super Unleaded 97 octane.
If I run it on standard unleaded fuel (95 octane), it runs like a bag of crap.

 

[Ron]

Man, this is like asking what religion is the best. I wont tell you what you should use, but I will tell you what I use. I use, and have used since about '81, Maxima Castor 927 mixed at 32:1 in everything from my '72 Penton 100 to my '96 Honda CR500. There is no better oil for an air cooled two stroke than a castor based oil, even 100% synthetics can not match the high heat handling capabilities of castor.

I aggree with Brian 100%, castor oils increase in lubricity the hotter they get, well beyond the flash point of synthetics, but a word of caution.
You can not let un-used Maxima Castor 927 premix sit around in your gas can or in your bike.
And I'm not just talking about your gas tank. Let the bike sit for a month in cool weather and you will literally find large beads of water in your engines cylinder and crankcase.
Castor oils are Hydroscopic and attract moisture. That moisture can get away from you very quickly.
Use it all and dump the rest.

But, the absolute best oil to use is.....................................................................................just kidding

 

[Zomby woof]

That's pretty much 100% untrue. Maxima 927 is primarily a synthetic oil with some castor, and it doesn't attract moisture anymore than any other premix.

Here is the go-to for premix info.


http://www.maximausa.com/tech-tips/oil-migration.php

 

[stormer254]

As you can see every body has a different opinion and a different truth, but like Grouty and Kartwheel offered, here is what I use. For my older bikes 60- 74 I use castor oil at 25-1, for twinshock/ evo I use Silkolene at 25-1, for my modern bike I use Silkolene at 50-1. 97 octane petrol with a booster that takes it up to 101 octane. I do not leave the fuel in the tank if I am not riding but drain in to a sealed can, modern fuel contains ethanol that does absorb water and block jets and generally f..ks things up, Also don't see much point in letting the expensive booster evaporate away. But what ever oil ratio you decide to use you must check your mixture as changing the oil ratio effects the mixture.

 

[juicypips]

2smokes i run my
wr360 02 at 45-1
kmx 89 at 82-1 both watercooled and with any fully simpathetic oil. usually silkoline as i buy in 5l tubs.
wouldnt recomend running less that 45-1 on mxer specially if its air cooled.

 

[Kartwheel68]

This is more specific to the 125/ 175 but do you run race gas or just high test? I've read a few things indicating current gas isn't quite as good as the stuff from 30 years ago but I'd be interested in what you have to say since you clearly have extensive real-world experience with these bikes.

Thanks,
Chuck

Yes, I run 50/50 race fuel and NON-ethanol pump fuel, and the air cooled bikes need it. They were designed to run on the highest octane pump fuel at the time which was 99. With a mix of race/pump I get right at 99 octane and dont waste money on straight race fuel. I've got 30+ bikes and I use it in every bike even though my modern bikes dont need the race fuel, I'm too lazy to mix different fuels for different bikes.

 

[Ron]

That's pretty much 100% untrue. Maxima 927 is primarily a synthetic oil with some castor, and it doesn't attract moisture anymore than any other premix.

Here is the go-to for premix info.


http://www.maximausa.com/tech-tips/oil-migration.php

I raced my bike at the Elsinore GP last Nov 12, 2012 and siezed it. I left it sit until a couple weeks ago, so call it 2 months.
Arguably it was hot enough to evaporate any condensation it may have had before it siezed.
When I took it apart I found a considerable amount of large beads of water on top of the piston and in the crankcase. I didn't anticipate seeing any.
I don't have another explanation except castor oil is hydroscopic, whether straight or blended.
I don't intend to stop using Maxima 927, but I won't be storing any.

 

[Kartwheel68]

Ron, I think your condensation is a lot more likely to have come from ethanol in the fuel than from the castor, but who knows? Its a bad idea to store mixed fuel no matter what kind of oil you use, mixed oil gradually loses its lubricating qualities over times so I try to never mix more than I can use in one weekend.

The bottom line is, it is really hard to get a BAD oil today, none of them are bad choices unless you tried using $6 gal Walmart outboard oil.

Here is an excellent article written by Harry Klemm, the man who built all the team bikes for DG racing back in the 70s, and has run a jet ski hop-up business for a long time. He is now back into vintage bike modification. He explains oils and pre-mix, dispels some myths about pre-mixes and lays out the case for castor based oils.

http://www.klemmvintage.com/oils.htm

He also has an excellent article on fuels and why these old bikes, designed to run on pump fuels with much higher octane than todays pump fuels, really should have some mixture of race fuel.

http://www.klemmvintage.com/gasolines.htm

 

[Zomby woof]

Ethanol does not "attract" water, but it is capable of mixing with it in very small amounts. A typical E10 fuel can accept up to .5% water. Gasoline "attracts" water in exactly the same way and amount that Ethanol does (it doesn't), but cannot mix. The water remains in separation. If you suspect that you have water in your fuel, or will, E10 is much better to use. Once again, ethanol does NOT "attract" water.

You probably had water in your gas. Maybe that's why you had an engine failure. I've used 927 exclusively in my 125 since 2007, and usually mix about one month's worth at a time. The bike gets a tear down at the middle and end of the season for ring/piston ring, and I've never seen any indication of water in the oil, gas, or crankcase. I mix it with 91 octane E10

 

[adam6402]

I run saturated fats and fish oil blend at 10:1 :-)

 

[Kartwheel68]

Ethanol is hygroscopic and miscible with water, it absolutely will absorb water from the atmosphere which is not completely a bad thing. Ethanol is both a good and bad thing in fuel. The good part is small amounts of water will be absorbed by the ethanol and harmlessly burned in the combustion event, and it is also an octane booster, while straight gasoline water will fall straight to the bottom of the tank. The bad part is most cars and motorcycles suffer severe corrosion problems if ethanol is left in the fuel system long term.

 

[cgmjr]

Looking at VP's line of fuels, I notice that some are oxygenated (like C12), others aren't (U4.4). What do y'all advise?

 

[edmoto]

I run saturated fats and fish oil blend at 10:1 :-)

Then the OP's mention of a "450" represents your cholesterol level, not cc. How many kicks does it take to get your body moving?

 

[adam6402]

It was mentioned above that overtime premix will be less effective at lubricating the engine, I would think the opposite would be true as I would expect the gasoline to evaporate leaving more oil to mix with the remaining gas. In aluminum tanked huskies, I've really not cared or worried about running the bike with 2 month old premix.

I should add that I always drain the float bowl before parking it for any length of time.

Maybe I should be?

 

[Kartwheel68]

I forget where I read it, but I dont think its a matter of the amount of oil to gas, I think the oil being mixed in the fuel causes the oil molecule to break down reducing its lubricating qualities. I downloaded an article about it a while back, I'll see if I can find it again. Having said that, at times I have stored fuel in both the bike's tank and in a can, and I have never had any issues, so it might not be a huge deal.

 

[2premo]

Eric frm Pasadena told me he was doing doing work on Husky and KTM engines with Golden Spectro at 100:1 and never saw any wear
He convinced me so now I run it at 50:1 as I am not as gutsy as he is
No problems with wear to report
On another note leaving mixed fuel sitting cause the fuel to be partially contaminated and affects the octane

 

[suprize]

Ive had the my newish KTM on 100: 1 and 80:1 motorex (synthetic) and just pulled it down for a 3 year look inside and its fine, a new slug and another 3 years will go by. I like the thought of less oil more gas in the chamber at any time. ive done a couple of tanks of the same fuel in the husky and all is well. it also runs the chainsaw, whipper snipper and blower vac. occasionally a few litres goes into the 307 chev to provide a little upper cylinder lube....