Best 2 stroke oil?

[Robert Taylor]

methanol/nitro mix used for drag racing never had any problems
also used it in a road race bike same (methanol only)
I think it was made for model engines/snow bugs
the mix was the trick

Yes we used with methanol as well and wear rate was rapid compared to other more up to the minute oil.

[malcy25]

I think you'll find that the people that did the dyno testing from where that quote about the "14:1 made best power" came from knew that they would need to re-jet each time time they made a change to the oil.

Extra lube especially the 'good' synthetics don't gum up like the old castor based oils did if they were to rich.

I've not had any experience with castor oils, but I fail to see their application in todays modern oil tech.

I've never had any oil related engine issues from synthetics, the only one time I did seize a bike that I was running was when I had a horrendous amount of ignition advance (timing plate slipped) and it detonated itself to death.

I have how ever had a recent play with making a big jump from running 40:1 in my bucket racer (Air cooled Honda H100, making a touch under 20HP) to 25:1. The main thing i noticed was that the extra lube seemed to help keep the engine temp down. One of the biggest issues with air cooled 2 strokes is when they get hot, they lose power. I can't feel any drop off in performance any more, and on top of that, the motor certainly feels much stronger in the low RPM, which I would put down to better sealing if the piston rings thanks to the extra oil.

Next time I have a chance to put the bike on the dyno, I will try the different ratios back to back. It would be interesting to find out.

I would say it is more than reasonable to use any modern good quality synthetic oil, and anything under 40:1 and your safe as houses.

Sketchy. Good post - One thing though is I understand that castor based oils whilst can be messy, still match or exceed many synthetics in "shear strength". It still makes a great gearbox oil and 4 stroke engine oil in some cirumstances. Interestingly in 2 stroke application low ratios 500 -100:1 seems to cause more ash than high ie 16:1. Dunno why.

[Madmax]

Yes we used with methanol as well and wear rate was rapid compared to other more up to the minute oil.

never had a prob with it
does not like oil injectolube
i pulled the heads 1 hr
was the only oil that (liked) would have anything to do with nitro
H1r/H2r parts are hard to find

[montsta56]

has anyone had any experience using the Mobil 1 2t race oil??.
I'm currently using the Elf 976 but the Mobil 1 seem's well priced??

[FruitLooPs]

I read an interesting post on 2T oils on an NSR forum the other day. I managed to seize my NSR250 first time I took it out on the track premixing with Castrol TTS at Ruapuna end of the front straight.

Now i've run my RG150 ragged in streetstock quite a few times and never had a problem using TTS for injector. I found this interesting:


"Shutting off after WOT can be an issue on pre-mix, the engine is being starved of fresh lubricant. This is where the performance of any given pre-mix race oil is really tested. It requires the oil to maintain a full film on the piston wall, supplied from the last charge of air / fuel / oil when the throttle was last open. Imagine shutting off at 11,000 into the corner after a straight, high engine RPM and downchanging which applies load to the engine (not as high as full power load). If the oil film is not strong enough (lower viscosity), it begins to breakdown and the piston comes into full boundary contact with the cylinder, and adhesive wear conditions start. Sustaining this for a full track day can then lead to seizure.

Oil Injector systems get by with a lower viscosity oil under these conditions as they still give a small feed of oil when the throttle is fully closed, thus replenishing the oil film on the piston / bore.

The viscosity numbers are very telling:

Castrol TTS, viscosity @ 40 C = 43 centistokes (mm2/s)
Castrol XR77, viscosity @ 40 C = 112 centistokes (mm2/s)

Almost 3 times the viscosity, which is really going to help when running the engine hot and the throttle is shut-off after WOT, when on pre-mix lubrication."

and another response from same forum by a tuner TYGA

"I used to spend time in the Castrol technology centre, and watching a single cylinder, air cooled 125cc engine run flat out on the dyno, being fed A747 @ 300:1 was quite nail biting. Only lasted a few seconds, but was quite impressive.

No other oil (race or street) came close to A747 for sustained high RPM use. Next in line was TTS, which was very closely followed (and beaten in some tests) by Shell Advance SX."