2 stroke fuel mixture

[Lozza]

Leith Super Shite Auto usually stocks the full range of Penrite Oils that's what I was asking.I'll still be running with castor.

[LWC82PE]

yeah castor is good but you really gotta be pulling your motor apart regularly and cleaning it as it leaves a lot of deposits right? it also attracts moisture so you should use it all at once and not leave bottles half full of it around the place to use later on down the track.

[Lozza]

If your leaving deposits it's down to jetting and ignition not the oil,if it's hydroscopic then use castor synthetic.

[pokey]

after reading all the blurb on advertising and this ones got  new improved XYZ with fortified bullshit it dont take too long to start questioning  and think  logically. Synth oils are being  manufactured  to cater for the environmental aspects  not soley for performance as  mineral oils obviously are or they wouldnt bloody sell any and companies wouldnt  buy it and oil companies wouldnt bother making it...

 Yeah some synth are okay in some engines ... same as Ethanol is okay in some engines. Not mine though


 Lets face it aircooled MX engines  get a lot of issues to contend with.  Heat and rapid increase and decreases of revs and I dont want to take the risk with any of my engines  as some parts  are getting harder to find.
 
 have tried synths and while the performance  seems similar  i always had glazing on bore and piston  even after a few rides. Was a little scoring on the exhaust  as well.

 I read someplace that the only thing that would save an english bigend is castor. Have used that for a few tanks and it does work well . no heat issues  but lots of smoke and i found it a bit gummy if you left fuel in the bike for a while and a lot of coking in the pipe.

minerals for me work and I will continue to use them and tune my bikes for them  and run them 20/25:1. Reasonably clean engines minimal scuffing and  decent  intervals between major services. after all the company designed them for mineral oils. I even use mineral in my car as i trust it to do what its ment to do... protect not just lubricate.

[Nathan S]

I've been running Motul M800 at 20:1.
My CT1 wasn't fresh when I got it - to the point that the previous owner strongly suggested that I fit the new rings he supplied before i raced it (I didn't...). I don't know what oil/ratio he ran it on.
After I killed the gearbox at the 07 Nats, I pulled it down. Everything was like new. Impressed and a little surprised, I didn't even bother to fit the new rings.

After a few more race meets, I pulled the top end off again the other night. Still like new - the ring still has the chamfer intact.

All of this is despite running a pod filter that hangs out in the breeze and my discovery that even though the power flattens off, it still revs happily when you're in a desperate situation (like trying to beat the previous owner.... ).

So... I'm happy enough to just keep doing the same.

[BJJ]

My 2 Euros.

After a few months return to VMX racing in '06 and me being the only machine that was smoking when hot on 25:1 Motul,   I went down to 40:1 Mobil 2-stroke racing oil from Big-W. 
-80's bike are showing no sign of wear. 
-MXa is suspended in silence,  but I am guessing it is big end.
You can read the manuals,  but remember,  the fuel is different these days,  than 30 years ago.

[Lozza]

http://www.locastros.com/piston_oil_ratios.htm

[Lozza]

Me and Spanky would get on fine

http://www.motocross.com/forum/posts/list/15/16966.page

[Doc]

33.333333 recurring:1 or 30ml per litre..always have always will run this ratio regardless of the oil brand used. 90% of the time it's TTS or Caltex semi-synthetic if I'm poor R30 smells beautiful and I've a few bottles of A747 in the garage but yet to try it, was thinking it could be nice for dirt track and the constant high rpm

[pmc57]

Lozza,
Great article on oil mix and jetting. I find it hard to understand that many people still link oil mix ratios with lean / rich.
I for one always want to run my two stroke engine with sufficient lurication first, at least I know all the essential parts are getting lubricated as they should.
pmc57

[Lozza]

I never thought about the residual oil in the case before I read that, and the fuel evaporation bit is spot on as fuel has a very low boiling point.Besides he repeated the Jennings/Bell tests and found the exact same things.Best myth busted was the to much oil/plug fouling one.

[Freakshow]

i have the original jennings article in a PDf here, if someone can host it , put it up in here as its a good read.

[Gerard De Ruyter (Twistandshout)]

that motocross.com forum guy sure seems to know his stuff.  i guess i was also operating under the misapprehension that reducing the oil in my premix might help fix my plug fouling problem.  so back to 32 to 1 i go.  i did lower the float bowl before last race, and the plug stayed fine, so that might be a partial (or complete) fix.  i'll see how she goes next race, then maybe adjust pilot screw and or lower needle a notch. 

but its good news really, if by putting more oil back in, you don't just get longer engine life (obvious) but also better torque and power.

[Gerard De Ruyter (Twistandshout)]

freakshow, send the pdf to graeme m, he'll put it up (for everyone's benefit).  he's that kind of guy.

[Lozza]

The link is on the previous page