Super Jet 40:1 or 50:1

[Rushford_Ripper]

I usually run 40:1 in all my skis even if 50:1 is called for, I like the little extra. I now have a Ada head installed and with the higher compression, wasn't sure if I should be running it now at 50:1. Does it matter that little bit with higher compression?

 

[Harbor]

Stay with the 40:1, i have similar mods plus more and even higher compression still running 40:1

 

[Vumad]

I was told by reliable sources for run 50 on my Yamaha and 40 on my kawi, so I run everything at 45. I don't think it matters that much until after you move away from a stock motor with bolt ons.

 

[Tyler Zane]

Bumping up compression doesn't call for running more oil, i'd be more concerned with what octane fuel your running. As for oil mix ratios, I have always ran 50:1 even on a highly modified jetworks setup but too much is better than to little (obviously!). If 40:1 makes you sleep better, so be it.

 

[SXIPro]

45:1 for me. My builder recommended it , so that's good enough for me.

 

[Harbor]

IF you've run 40:1 in the past without issue then now Mod your engine why deviate and go 50:1.?

What's the logic ?

I ran 50:1 because the service manual said too for like 4 or 5 years on 190 psi, type 4 dry pipe, water injected, enhancer, limited boat with out issue. But when I took it apart for an overhaul it seemed real dry inside.

What's your builder of parts supplier recommend you run ?

What oil are you running ?

 

[jetpilot36]

i have 0 hours on my new motor. going to the lake tomorrow so I have to break here in gently. im actually running 2 gallons of 32:1 then switching to 40 to 1.

 

[CRJ]

Break in should always be 32-35:1. Then 40:1 for atleast two or three tanks. let the rings seat, let the crank find its happy place. Then go to 50:1. First ride of the year i run 40:1 for tht weekend, after its always 50:1. Youll get a bit more braap too.

 

[Rushford_Ripper]

I always run:

40:1
93 octane
Amzoil marine
-(the blue hp stuff)

 

[fast superjet chase]

Full mod race ski, full ameture freestyle ski and I run 50:1 if you are mixing it to rich it will actually lean it out cause too much oil in the fuel and won't let it flow through the jets causing it to lean out always run what is called for in the manual.

 

[catpower]

Thoughts?

 

[DAG]

show me the data

 

[mybad]

Spoke with Harry from Group K about ratios last week. He suggested 32:1 if your running a modified engine hard. Otherwise 40:1. He also added that race fuel loves oil and mentioned the big factory dirt racers have been known to run much heavier than 32:1. A very knowledgeable and experienced guy.

 

[kevbo]

Noooo, that procedure is for fourstokes. The problem with new twostrokes is overheating the pston. Extra blowby from unseated rings makes it worse. You want to reduce combustion temps until the top end has some run time. This can be accomplished by running below the pipe for a while (for standups) and/or by opening the top screw until power is lost (sitdowns).

 

[Sparkplug]

For a long time I ran blue gas. That's how I measured it. Seriously. Recently like the last 6 months, I fill up one of the 12 Oz pale ale bottles that's always around the back of my truck, for 5 gallons. That's gotta be close to 40:1 right?

Anyways I've never blown up an engine. I've put over 1000 hours on my skis total. Unless your running a built billet engine, or your racing and trying to shave tenths, I don't think the ratio of your fuel is going to matter much if at all. Better to spend that time riding Instead of worrying imo

 

[DAG]

Just run leaded fuel, no oil needed lol

 

[SmittySX]

On all my skis I run 45:1 93 octane and klotz r50. All Yamaha engines under 185 psi and stock (ish) timing.
I've got one motor pushing 235psi, vp116, running 32:1.

 

[catpower]

Oil has a greater btu content than gas. Heavier ratio and more heat. This is where higher octane is more important than oil ratio imo. I agree with Harry. He suggested 32-1 and his site recommends superM IF you run hard ie: very high rpms

 

[Jakobi86]

I believe I've read reports that the most power is made at below 32:1 by quite a bit, but the gas/oil ratio through the carb jet is right on. Basically the more oil you add the less gas will go trough, leaning it out. I've always broke in my engines with a few heat cycles and ten applying full load. Not full throttle, full load on the engine. Those rings NEED to be forced out to the wall so they can seat. There's a window of time here and most of its gone before a full tank is


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[Quinc]

I run 45:1 when running 91 octane pump gas and 50:1 when running 50/50 a/v low lead. @Tyrant1919 might be able to run some tests with different oil rations when he finishes his computer setup.
http://www.x-h2o.com/index.php?threads/project-onboard-telemetry.148587/