Premix Ratios

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Oct 20, 2003
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#1
The KTM workshop manual states thet premix ratios should be between 40:1 and 60:1 depending on oil quality. What does this mean? What affect does this have on a two stroke other than the obvious. What affect on power, jetting, engine life. Im confused that they dont just say use product "A" at XX:1. I ride a KTM 200EXC and was told by the dealer to run in at 33:1 and then switch to 40:1. What does all this mean? Run on the lean side with jetting at 40:1 and on the rich side at 60:1 or just right at 50:1. Of course I want a reliable and safe mixture, but I also want maximum power.
Any explanation would be greatly appreciated
Insane
 
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#2
Poo Poo on all that B.S. just mix it 40:1 and use a good oil. I use Honda HP-2 myself, it's high but when compared to a new motor, very inexpensive.
 

wsmc831

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#3
ya, don't beat yourself up too much over everything. I personally run about 45-1 but highly doubt you'd notice much difference in the range of 40-60-1. As far as quality of oil, the synthetics do a better job, I personally run Motul 600, but there are lot's of high quality ones out there. Heard good things about Amsoil and Mobil to name a few....
 

Jaybird

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#5
I run ~20-26:1 in my 125
Mobil MX2T

Pick a ratio and stick with it. (Jet to it)

There are slight performance advantages to running alot of oil, as well as protection advantages.
Dealers, and mfg's making blanket statements about where your ratio should be is a load of crap, IMO. They have no idea what oil you are using and what conditions you ride in, and consequently they have no idea what they are saying. They do sound superior when they tell you what to do though...it makes them and sometimes, you the buyer, feel better.

For oprtimum performance in all circuits, jet your carburator properly for what ever ratio you are running and for the type of riding you do.
If you are gonna change something, change fuel and not ratio.

I personally would never run less oil than 40:1 in any dirt bike. I wouldn't care if Amzoil sent me a case of it, I would never run 100:1 (I wouldn't run Amzoil on a bet anyway...but that's another thread :) )
 
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#6
Thanks guys, with so much information on the forums and strange statements in the manuals, it is easy to become confused. Ive settled with BP Ultimate 98 and Motul 800 at 40:1. Jetted like a maniac and have the motor running sweet.
 

Patman

Pantless Wonder
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#8
Originally posted by Jaybird
I personally would never run less oil than 40:1 in any dirt bike. I wouldn't care if Amzoil sent me a case of it, I would never run 100:1 (I wouldn't run Amzoil on a bet anyway...but that's another thread :) )
LOL! I wouldn't run it at 100:1 either as the 100:1 product is specifically for small engines that require a 100:1 premix and for no other use. That's sort or like using a screwdriver as a pry bar, it will work but it might also not. ;)

The Series 2000 product is an exceptional product with a suggested mix of 50:1 but I personally have experience with it at 40:1 thru 80:1. My Montesa 315R runs a 80:1 mix with VP MR2 and it still is both spotless inside and shows the hatch marks. Messed around with ratios on my KTM 360 and found the 50:1 worked just fine but I wasn't searching for evey last iota of power either. I tried the Amsoil 2000 product after getting tired of the exceptionally high price of Motul and am very happy. Motul, Mobil & Motorex also seem to have top shelf products.
 
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#9
Have had great experience with Amsoil - Motul as well. Dad's an Amsoil distributor, so use it in everything, so a little bias. Had Husky for four years - unbelievably low wear on engine/tranny. Also, Huskies have pre-installed zirks - I think five - used Amsoil sythetic grease - no wear on bearings.

50-1 worked well.

Alooooooha!!!
TrailTramp
 
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#10
mix what manufacteror of oil tells you to. Usually a top of the line oil comes with just enough in their small bottles to mix with 4-6 gallons. I personally use golden-spectro 1 pint to 5 gal i think this is around 52:1 or so didnt do the math. The more oil you add the leaner your bike runs. Its just like cool aid you got to read the instructions. If you buy bulk oil you run the risk of hydrous contamination, I always buy small containers
 
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#11
Originally posted by gabriel
1 pint to 5 gal i think this is around 52:1 or so didnt do the math.
I should say!

One pint oil to 5 gallons of gas results in a gas to oil ratio of 40:1.
 
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#12
I use Spectro oil and 93 octane pump gas at 40-1.

I thought everyone used about the same ratio, I 'm wrong!!
 
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#13
I use anti coagulated animal fats at 16:1. It smells like breakfast wherever I go, and it's free. I just filter the leftover grease from the stove top. I did have to install a diesel fuel heater in my tank to keep it liquified. :-)=)


Mobile MX2T 36:1, works great. I have run Amsoil at 100:1 in my KTM 250, it was a big mistake, I ended up doing a couple of bottom ends within 6 months.
 
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#14
Originally posted by roostafish
I use anti coagulated animal fats at 16:1. It smells like breakfast wherever I go, and it's free. I just filter the leftover grease from the stove top. I did have to install a diesel fuel heater in my tank to keep it liquified. :-)=)
Down here in the south bacon grease works very well although opposum fat is premium - It just requires a bit more work to obtain. I don't use the tank heater thing since the fat dissolves well in the gas but I did hook up a paint mixer w/some duck tape just to keep it that way.

Mobil 1MX2T @40:1 with 50/50 race gas/92 pump