Comparison 25:1 vs 32:1 premix

[Blaaster]

Last Sunday I did an experiment with premix fuel ratios.
Running the same oil for a Moto Cross meeting the oil was Maxima Castor 927.
The first half the meet was using 25:1 the second half I switched to a 32:1 mix.

At 25:1 the Blaster as usual was keeping up with the larger 4 strokes and holding it's own, but using 32:1 and one size down main jet to compensate, I noticed a little difference, it took more effort and a lot more risk taking to compete with the bigger bikes. I am switching back to my beloved 25:1

Has anyone else tried a fuel/oil ratio comparison if so I would be interested in your findings

 

[CARNZ]

I've used different fuel-oil ratios in my Zilla and didn't really notice a difference other than that I had to re-jet.

 

[Blaaster]

It's back to 25:1 and a 320 main jet and it is awake again.

 

[Paulie B]

25:1 is extreme are you sure your not beating everyone by choking them out lol
I always ran 28:1 in the Blasty on alcohol but thats pretty normal.
I run 32:1 in the Shee.
I haven't noticed any performance gain from running more oil but there ain't nothing wrong with it. Hells maybe your motor will live a longer life.
Watch out for carbon build up in the head and exhaust pipe as well as spooge cloggin up your silencer packing.

 

[Blaaster]

Smokes a little more than 32:1 at start up and after a period of idling, but once hot only a wisp of smoke. I must admit that a few people in the pits have had tears in their eyes when the throttle is blipped to clear it out.


I run 98 octane and with MX the throttle is nearly always wide open and runs pretty hot as speeds are not that great allowing good air flow. Where we race they water the track well and there is always a build up of mud clinging to the cooling fins.


Sure as eggs are eggs the little 200cc will live a little longer and that is my aim.

I keep regular checks for carbon buildup and have not been unpleasantly surprised many times, although it has happened on the faster tracks.

As to spooge in the silencer packing, least of my worries. Aint had a DB meter aimed at me yet.

 

[Luni]

I honestly think the difference is more in the jetting than the oil mixture IMO. However, I have read an article that states if youre running castor based oil, more is generally better, its dyno proven etc.

So, it COULD be.

 

[Blaaster]

I have messed around with the jetting, using the usual tuning procedures and am pretty confident that I have the air/fuel ratio right. Might give 28:1 a shot and see if the compression decreases due to less oil hanging around the rings.

I only did the experiment as most Blasty owners on the forum seem to use 32:1 and are happy with it.
Another reason was to save a few dollars on oil, as I am now on a pension and cash is not as plentiful as it used to be.

I have used Castor for over 50 years and as I am a creature of habit I am reluctant to change, but just maybe I might try an Ester oil.

Any ideas.