Ya I don't really get the which burns hotter thing, it's meaningless

It's kinda like saying an elephant is bigger than a tiger so it must be more dangerous

Actually a car tire burns hotter than oil or gas so maybe put that in your bike

If our oils were designed to be burned to create power, they would be completely different, and not to mention, the engine would be very different as well, like maybe a turbine?

our oils are designed to be added to fuel to lube the engine, NOT to make power all by itself

Any way, back to our regularly scheduled program, the best power is with the correct ratio for the intended usage

High RPM, or extreme loads require more oil, low RPM moderate loads like what we do won't be able to use the oil and it will build up so we are back to the question

Some bikes and some riders will need more oil, some will not, look at like this, put an entry level rider on Adam Raga's bike and it might foul the plug or ooze goop out the silencer tip

Climb a long steep hill and see if you bike is puking clouds of smoke, that will tell you if you are using your oil up or just plugging up your exhaust with it

I don't think there is a definitive answer to this unless you have what the engineers use, that is a spark plug that measures combustion temperature, even then, oil ratio will be different for conditions, riders and brands of oil

Say Cope,

Do the answers change if you are trail-riding the bike (not trials,) trying to keep up with the pack on their enduro bikes?

More oil then? Or no need?

Jeff

Just seen this question, sorry.

I think it could make a difference depending upon if you are talking high speed trail running or constant speeds for long duration. As example, I have never seen problems with riders running hard on a trials loop of long duration, but they are on and off the gas, mid range average, so 70-80:1 seems sufficient.

Events with road work and constant mid to high operation, I might tend to go nearer 50:1 ratio, still letting things rest a bit at times. The cooling systems are limited as well, you know, not built as a road racer or long WOT operator!

Use discretion and common sense here!

Thats why I use 60:1 for general riding. Insurance for the odd thrash. Not too oily for slow stuff and residues burnt of quick.

If I were going to a very tight site for the day I too would mix 70:1 or closer to 50:1 if going to open moorland or marshalling an enduro etc.

Thanks, that all helps!

Jeff

Thanks Ted. I think this must be what happened to me -

file://localhost/Users/jeffjen/Desktop/Trail-riding%20Meltdown%20-%20Is%20Race%20Gas%20The%20Answer%3F%20-%20Gas%20Gas%20-%20Trials%20Central.webloc

So would you guess that I need to go up 2 sizes on the Main jet?

Jeff

Not necassariely up jetting Jeff ,you may have to just raise the needle hight ,or even drop a jet size and raise the needle deppends on several things . Best thing to do is perform a plug chop . Your engine is in good condition i take it ?If you research the web or maybe speak to the likes of Kev from Gas Gas uk they may advise you directly .By rule of thumb ,if you jet up you are allowing more fuel mix through but you may rob your engine of tractabillity or throttle response . If you raise the needle you are letting more fuel through for a given throttle position.

Let us know what you find , i like this kind of stuff .

Ted .

F#cking hell 120:1!! 50:1 does great. I mean do you want to fu# k your engine up or something

Have used 128-1 ratio as recommended in my 95 350 gasser since new. Still on the original top end.Since it has not "f"d up my motor it must be something.

Simply as a point of interest, Yamaha has always factory recommended 100:1 for outboards

And nothing has greater consistent loads than an outboard, they pretty much match a Dyno for operating conditions

Granted, fairly low rpm @6000 and a pretty effective cooling system but ........

May stand corrected here . Running an out board at 100;1 has more to do with whats being pushed into the water through the exhaust .As part of my duties ,i pilot an M.O.B rescue craft, both the Danish and Norwiegen marine authority insist on low hydrocarbon emsision oils for that type of 2 stroke craft and as you state the motor pumps the cold (always )water around the motor . I would say that if you run an engine at 60:1 the oil can do it's job , lubricate and aid cooling the bearings, provide better piston ring seal thus aiding combustion . 100:1 may work but personally i think thats very low amount . The less of it ,the least effectively it does it's job . Also a dyno tests air fuel ratio at given rpm as well as B.H.P at given throttle openings and full throttle . Bit different than a small marine engine

This is brill ,all this information on just this one subject . Fuel ratio !

Be safe .

And may I ad another thing in the mix (haaa... ha... ha..... ha)

Does anyone use alkylate fuels as I do in my four-stroke?

Should run a lot cleaner (and better for humans and the environment), also in two-stroke engines...

http://www.acs.total.com/en/fuels/industry-fuels/alkylate-fuel.html

Guys ,is thar the sweet smelling stuff you buy at the pumps which is for sale in most European countries comes in two grades ? This was making an appearence in France 18 months ago .

No, at least in Belgium it's not availeble at the pump. It's mostly sold in garden centers for use in lawnmowers etc.

I use the Aspen 4 (euro 95 RON octane) fuel in my 4-stroke. But it's also available in a ready-to-use 2-stroke mix

http://www.gustharts.com/lubricants-%26-fuel/aspen-fuel/

Aspen has racing fuels also: Aspen+ ( 98 RON octane) and Aspen R ( 102 RON octane)

They even sell Aspen E which is a bio ethanol based racing fuel

I find it amusing all the theorizing that folks like to throw out on oil ratios and the like. I just leave it to the experts, and pretty much run what the manufacturer recommends. 80-1 in my '02 GG TXT Pro and 40-1 in my YZ250. I'm an average rider, and always use high quality synthetic, so figure that the recommendations will work fine for me and using high quality oil buys me a bit of extra "insurance".

So far they have.

Like many hear have noted, jetting properly seems to have more impact on spooge out the back and/or crud build up on the piston than overall mix ratio.

The whole question is irrelavent unless you have a clean and sorted air filter. Any changes here and you will get engine damage from either weak running if a hole is in the filter or dirt. A blocked or wet filter also means it'll run rich as a pig and you'll get spooge even if your jetting and mix is spot on..