motopsycho87
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Flashpoints only importance is before combustion. If you're getting spooge, it's not to do with Flashpoint, but rich jetting again...
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motopsycho87
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http://49ccscoot.proboards.com/thread/4871/stroke-oil-comparison
Is a good thread, it's not perfect conditions, but you can clearly see for yourself the effects of lower oil ratios vs high. Better mpg, freer revving, less wear with more oil, and cleaner too! Why would you not?
Is a good thread, it's not perfect conditions, but you can clearly see for yourself the effects of lower oil ratios vs high. Better mpg, freer revving, less wear with more oil, and cleaner too! Why would you not?
motopsycho87
New member
Also. Remember nit too long ago, 10,000mile always expected from the top end of any 2 stroke, now we have forged pistons and nikasil bores, forging increases the toughness and strength of the piston, the tighter tolerances allowable from nikasil lining reduce the amount of force applied to the skirts also.
Everyone seems to think new 2 strokes are ticking time bombs, but as long as you maintain them properly, they will run much longer than 'expected' by most.
Everyone seems to think new 2 strokes are ticking time bombs, but as long as you maintain them properly, they will run much longer than 'expected' by most.
motopsycho87
New member
Has any thread mentioning 2 stroke mix or preference of oil ever ended?
hadfield4wd
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motopsycho87
New member
Dot 4 or dot 5.1? Tyres that is...
gasser
New member
I partially disagree. Oil that isn't burned during combustion (gas too) is expelled out the exhaust as spooge. Spooge is what results when unburned fuel cools after combustion. Different engines and different riders have different needs when it comes to oil and that is due to flashpoint. Smaller engines run hotter and higher rpms create more heat so a high flashpoint works well. It does not work well on a 300cc 2stroke that is ridden at low rpms - it will load up because not enough of the oil is burned. On a MX track or open trails where you can keep the 300 spinning a highpoint oil is fine. If you doubt this try running a 300 on your favorite tight, hilly single track with Motul 710 oil then again with Motul 800 oil and you'll see the difference.
motopsycho87
New member
I've not had a problem really when riding woods either though, I always give it a scream before I attempt a hill climb, but don't get the splutter most do.
The Flashpoint of motul 800 is 252c, exhaust gas temperatures in 2 strokes reach in excess of 800c, thus 'spooge' is more likely due to improper atomisation than the Flashpoint of something making approximately ;
50:1 = 0.02 or 2% of fuel mix.
Stoichiometric ratio of air/petrol is 14.7:1 (so similar to atmospheric pressure... Coincidence? Unsure tbf), but most tuners run to 13:1 as cooling and lubrication are considered more important than an entirely clean burn, and yield greater results on the dyno.
So, 13:1 = 0.076 or 7.6% of air/fuel mix is fuel/oil
So if my math is correct, 0.076 x 0.02 = 0.00152 or 0.152% of total air/fuel charge is oil with a flash point almost 4 times lower than exhaust gas temperatures. If you can't burn that, then you've got problems.
Now I can understand going from 710 to 800, or 88c to 252c Flashpoint causing spooge if atomisation isn't complete, and without injection, atomisation will never be complete, but with the amount of turbulence caused in a 2 stroke engine, it should be negligible.
The Flashpoint of motul 800 is 252c, exhaust gas temperatures in 2 strokes reach in excess of 800c, thus 'spooge' is more likely due to improper atomisation than the Flashpoint of something making approximately ;
50:1 = 0.02 or 2% of fuel mix.
Stoichiometric ratio of air/petrol is 14.7:1 (so similar to atmospheric pressure... Coincidence? Unsure tbf), but most tuners run to 13:1 as cooling and lubrication are considered more important than an entirely clean burn, and yield greater results on the dyno.
So, 13:1 = 0.076 or 7.6% of air/fuel mix is fuel/oil
So if my math is correct, 0.076 x 0.02 = 0.00152 or 0.152% of total air/fuel charge is oil with a flash point almost 4 times lower than exhaust gas temperatures. If you can't burn that, then you've got problems.
Now I can understand going from 710 to 800, or 88c to 252c Flashpoint causing spooge if atomisation isn't complete, and without injection, atomisation will never be complete, but with the amount of turbulence caused in a 2 stroke engine, it should be negligible.
Zman
Platinum Level Site Supporter
The R50 has a 550F flash point. The The Motorcycle Techniplate is around 275F (if I recall correctly as I cant seem to find the datasheets online this morning). With the same jetting the R50 spooges unless ridden hard and the Motorcycle Techniplate does not spooge.
memphis2857
New member
If your 2t engine has combustion temps at 800c or higher your piston is going to be a melted ball of goo. You may want to check your stats.
800 degrees Fahrenheit would be a more realistic number, but that's at WOT. The argument is that when puting around in the woods at low speeds the combustion temps aren't high enough to burn off oils with a high flashpoint. The oil then just lays in the pipe or in the crankcase. Then when you get to a high speed stretch the bike will burble, smoke, and spooge as it's trying to get rid of all the excess oil. I have experienced it first hand with Motul 800. I have since switched to amsoil dominator and haven't had any trouble.
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