Tuning Question

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yzfandy

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I believe I've got the low end sorted on my MT but not sure how far you can go on the top end.
My understanding of most two strokes is that they will get quicker and quicker by leaning the top out until they seize up. Thing is if I open the throttle wide open there is a slight hesitation before it picks up.
Not sure if this is due to me still running it at 25:1.
If its because the top is too rich and its bogging before the revs pick up
or something else like worn piston ring / poor ignition ect?

What do you look for when tuning the top needle. In nitro motor I'm looking for pitch, smoke fading out after 3 seconds of full throttle plug colouration but on these I haven't a clue.
 
tune your high speed first, use very small adjustments and check your plug...you want a nice chocolate brown...black and you're too rich...grey to white you're too lean. You want to hit max revs and then kill your motor asap..called a plug chop...then pull the plug and check the colour.
Once you got the h end set then set the L end and you'll find most of the lag will go.
 
tune your high speed first, use very small adjustments and check your plug...you want a nice chocolate brown...black and you're too rich...grey to white you're too lean. You want to hit max revs and then kill your motor asap..called a plug chop...then pull the plug and check the colour.
Once you got the h end set then set the L end and you'll find most of the lag will go.

sorry lads don't want to be butting in here, what is the correct oil fuel ratio on two strokes,reason i am asking is because the oil i have says the mixture is a 150mill to 5 liters,maybe this equates to the same mixture,i wonder what ratio would 150mill to 5 liters be?

sorry for butting in....
 
Tell me why the engine builder's and mfg recommend to use 25:1 oil mix and 91 octane
fuel..If it is to much oil? CY & Zeo engines...I can see 25:1 for break in new engine
the going to 32:1 mix after that....AKASlawhammer
 
I agree... 25:1 is just too much oil.

I am planing on going to 32:1 but will that mean I need to re-tune?

Also don't forget that here in the UK the minimum RON number that yo can buy is 95RON. Don't know if that should affect the mixture I should use!
 
The fuel octane ratings are the same they are just inflated to a different measurement in your area vs ours. Our 87/89 is your 95 and so on. Just use a good fuel of any type and you will be ok.

Are you using any type of tuned pipe or after market pipe? Is your motor bone stock or modified?

Stay at 25:1. Really measure out 25:1 and then measure out 32:1 is the extra going to hurt?
I run a 100:1 synthetic oil at 25:1 since I got into large scale and even tried leaning out to 30:1 and found no difference.
 
The fuel octane ratings are the same they are just inflated to a different measurement in your area vs ours. Our 87/89 is your 95 and so on. Just use a good fuel of any type and you will be ok.

Are you using any type of tuned pipe or after market pipe? Is your motor bone stock or modified?

Stay at 25:1. Really measure out 25:1 and then measure out 32:1 is the extra going to hurt?
I run a 100:1 synthetic oil at 25:1 since I got into large scale and even tried leaning out to 30:1 and found no difference.

sorry to interupt again btb, you see i am actualy very mixed up at the moment about my oil mixture,im as mixed up as the oil in my gallon :lol:
seriously, (and sorry yz fandy for butting in here)

you see i use rock oil castor oil,on the bottle there is nothing marked just a 150 ml to 5 liters of petrol,u see i want to define the ratio of this recomended mixture eg,25/1 or32/1, i am trying to figure what it would be??
any clues?
 
The fuel octane ratings are the same they are just inflated to a different measurement in your area vs ours. Our 87/89 is your 95 and so on. Just use a good fuel of any type and you will be ok.


I disagree with you with regards to the octane number. The RON in the Uk and States is (Road Octane number) which is a average of MON (Motor Octane Number) and RON( Research Octane Number) to give you a Road Octane Number( also RON). Some European countries do use the Research octane number on its own to inflate this figure but not the UK as of when lead in petrol went. Its one of the reasons why our fuel is so pricey over here
I'm just not sure if this would affect what oil ratio should be?

Are you using any type of tuned pipe or after market pipe? Is your motor bone stock or modified?

Yes I'm running a samba and as far as I know the motor is stock CY 29cc
 
I disagree with you with regards to the octane number. The RON in the Uk and States is (Road Octane number) which is a average of MON (Motor Octane Number) and RON( Research Octane Number) to give you a Road Octane Number( also RON). Some European countries do use the Research octane number on its own to inflate this figure but not the UK as of when lead in petrol went. Its one of the reasons why our fuel is so pricey over here

Your price is not due to better fuel. Better call your government on that one.:laugh: We may also be a that price soon if the 50% government fuel tax increase goes through?? :glare:

Here is an old post:

In Europe 98-octane gasoline is common and in Japan even 100-octane is readily available at the pumps, but this octane nomenclature is misleading to Americans as foreign octane ratings are derived entirely differently from our own... So, like every other measurement system it seems that everyone else uses a different scale than we do, but unlike most other instances where we have had the good sense to create different units of measure in this case we all use the same name...
Japan and Europe use a system called RON or Research Octane Number to determine the octane rating of their gasoline, while stateside we use a system called AKI or Anti-Knock Index to determine gasoline's octane rating... Interestingly, to further complicate things it would seem that our own AKI system is actually derived from the average of the RON system and another more complicated system referred to as MON or Motor Octane Number... So, to recap our methodologies for measuring gasoline's octane rating are different, but share some common elements...
So, with the commonality of RON in mind a good rule of thumb is as follows, multiply the foreign RON Octane rating by 0.95 and you will have the US AKI equivalent.

( RON Octane Rating x 0.95 = AKI Octane Rating )
98 RON Octane x 0.95 = 93.1 AKI Octane (US measure)
100 RON Octane x 0.95 = 95 AKI Octane (US measure)

So, as you can see the 93 or 94 octane fuel we are all paying an arm and a leg for is actually quite comparable to the higher octane fuels found in Europe and Japan. The people whom have to worry about low octane rating are our friends out west in places like California that are subjected to substandard 91 octane.
91 AKI Octane (US measure) = 95.5 RON Octane
 
Your price is not due to better fuel. Better call your government on that one.:laugh: We may also be a that price soon if the 50% government fuel tax increase goes through?? :glare:

Here is an old post:

my god that is interesting bigger the better,wouldnt like to be living in california,i would be using the old nitro boost bottle in the boot of my car.

thats a very low rating in ca,here in ireland i think we have much similar to usa,maybe a little higher 98octane.

should be 100...
 
Stay at 25:1. Really measure out 25:1 and then measure out 32:1 is the extra going to hurt?
I run a 100:1 synthetic oil at 25:1 since I got into large scale and even tried leaning out to 30:1 and found no difference.

The only reason I run 32:1 is because I don't like the smoke cloud from running a richer oil mix. It is entirely up to the person, I guess, run whatever makes you feel comfortable.
For a while, I was running Klotz R/C oil mixed at 50:1. I noticed a little more throttle response, but I think that was probably carb tuning. I got nervous so I dumped the rest of the gallon in my sled and went back to 32:1.

I know this a little off topic, but I remember reading on here; something about guys running Coleman camp fuel? Isn't that basically kerosene or alcohol, like what is in a Sterno heater? That stuff is like 11bucks a gallon, why not just run gasoline?

Thanks,
Trip..
 
I know this a little off topic, but I remember reading on here; something about guys running Coleman camp fuel? Isn't that basically kerosene or alcohol, like what is in a Sterno heater? That stuff is like 11bucks a gallon, why not just run gasoline?
Thanks,
Trip..

Yup alot of people still do. Its octane rating is somewhere at 50-55. It has no additives that gasoline has for valves etc. I could get it somewhere around 6-7.00 gallon here.

It was a better price when gas was higher. Wal-Mart has about one of the better prices for it. I found it worked well on smaller engines and less on 26 and up. My opinion but I went back to gas. Search on here, there is alot of info on it.

Sorry off topic.:glare:

You could get a "low smoke" formula like Amsoil Saber Pro. At 25:1 it smokes when cold but lessens to minimum when warm. Snowmobiling now thats some smoke.
 
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