OzVMX Forum
Clubroom => Tech Talk => Topic started by: southnztim on November 12, 2011, 04:58:52 am
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I'm currently running Avgas/oil ratio of 20:1 Works well and I like that amount of oil through the motor.
I would like to switch to methanol. What ratio should I use? If a bit over twice as much fuel is flowing through at the same rpm, do you halve the ratio to use the same amount of oil? Or does the extra fuel 'wash' the motor so you need more to keep it lubricated?
What is the difference between Castrol R and M. I've had a few people say to just use the R as its cheaper and easier to get and will do the job. But the M must be made for a reason.
Thanks, Tim
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i run 20:1 shell m in my 1973 cr250 dirttrack honda and now the same with my 1972 cz400.
cheers
jim
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Tim, use the same mix ratio with methanol as you did with the avgas, as far as your choice of oil, personally I would use M as the Karting fellas use it in their screaming little 2 strokes.
Foss
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I knew you 2 would reply to this.
They both sprinkle a little methanol on their weatbix.
Peas in a pod, the methanol brothers.
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It's luverly 50 / 50 with orange juice !! LOL
Foss
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yes older brothers sure have some influence on the younger ones as you well know steve
you must run petrol mre mix through your bike after each time you use it on methenol and also clean the carby a lot
jim
454
family race no
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What hope did we have?
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Thanks for that guys. Every bit of info helps. Certainly makes it heap of oil squirting through. Pure perfume!
Cheers, Tim
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the truth is for methonal you need slightly less due to the volume of fuel going thru the motor< twice as much> i would run about 170mm to 5 liters to start with and if it blows shit loads of smoke bring it down from there.
cheers slider
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On the topic of Castrol R V's Castrol M. Just prior to VMX titles this year I was after some Catrol R40 which is what I used to run in my Husky back in the late 70's, my local auto parts store wasn't able to get any R40 and gave me the phone number for Castrol tech support. I ended up talking with one of the people there who was quite happy to explain things. Castrol R was originally formulated for use in 4 T engines running on petrol, were as Castrol M has been specifically formulated to be mixed with Methanol and run in 2T engines. I happened to still have about 20L of M in my shed, and the Castrol guy said it even though it wwas designed for use with methanol, it would still mix ok with petrol, so long story short, I am now using up my stock of Castrol M.
CJ
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So if my maths isn't too far out, 170m is close to 30:1. I guess if it's blowing heaps of smoke at that, you'd have to be careful that its not just running too rich. I've played around down to 14:1 on petrol and had no problems with smoke or oiling plugs. So I'm not so much after what ratio to run as to the difference between methanol & avgas's flow amounts and how that effects the lubrication.
With the M CJ, Because its made for methanol, does that mean you don't need acetone to get it to mix?
Thanks, Tim
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Because its made for methanol, does that mean you don't need acetone to get it to mix?
I didn't ask the Castrol tech support guy, as I was more interested in wether it would mix ok with PULP. One would have to assume that if it was formulated to be used with methanol that it mixes ok without any other additives.
CJ
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it will mix no probs, just seperates after you park it. So only mix as much as you will use on the day.
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mix as much as you like i mix 10ltrs at a time and when i am finished racing drain out tank.run petrol through at 20:1 store bike when next meating is up week before clean carby shake premix up fill up tank ride bike.simple stores better than petrol it dosent go off as long as it is sealed. i run 20:1 its smokey at the start but clears out when raceing.nevery fouled a plig in the cr250m on methenol.atm i am tuming my cz400 to methenol use same mix still a bit rich but starts up easy all the time and it has an old plug in and runs points.go large in jets then come back with track plug chops
jim
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Hey Jim, perfect oportunity to do plug chop's on the CZ this weekend ;D
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I used to run Castrol R30 for years, until I got sick of it staining everything the fuel touched orange and massive carbon build up.
Switched to Maxima 937 and haven't looked back, it's light years ahead. No carbon, no stains, just as cheap and sweet smelling.