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2 stroke oil facts & myths


b40rt
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Fully synthetic from Stihl (which I use in my chainsaws) is fine in my mates 1927 Scott Squirrel. It's been drinking it for about 20 years, doesn't smoke, & goes like hell. Very much a ridden bike not a polished one. Seen him doing 70/80 many times. Can't quote a ratio as he has a Pilgrim Pump on it. 

Dick.

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29 minutes ago, old trials fanatic said:

FWIW i was told by the Motul rep ages ago that full synthetic in a trials bike doesnt burn away in the silencer because the motor doesnt get hot enough like a moto crosser or race bike so they recommended semi synthetic. Actually they recommended their "scooter oil". I've used semi synthetic ever since with no problem but i am sure many will disagree. Always a horny subject this with so many different "recommendations". As long as the user is happy then thats as good a result as you can hope for. 

Look at "flash point" at oil specs and choose lower ones to avoid oil spoonge at pipe

Motul 510 is going OK for me. Maybe will test the 710 someday. 

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6 hours ago, b40rt said:

Fully synthetic is fine for modern motors, not for our 50 year old ones. I think I have tried most, but have settled on Lucas semi sync. At around 32 to 1, that is 187 cc to 6 litres of fuel.  I may be right, or wrong, but my motors run just fine at that. "

This statement was posted in another forum, I asked for some evidence, or even a hair brained explanation, nothing !!

I'm not sure the o p actually rides at all, who mixes up 6 litres of 2 stroke ?  Is that overfilling a 5L can, or part filling a 10L can  ?  

Anybody care to comment ?

 

 

 

 

I replied to you original post ??

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7 minutes ago, cascao said:

Look at "flash point" at oil specs and choose lower ones to avoid oil spoonge at pipe

Motul 510 is going OK for me. Maybe will test the 710 someday. 

Agreed.  I learned my lesson about this.  Being lazy, I wanted to run one premix in all the motorcycles.

After some spooge issues, I did my homework.  The oil I know and love had a high flashpoint, causing the spooge issue.  Lubrication was certainly not a concern.

Most times it is recommended to run ratios with less oil than a manufacturer of the engine suggests.  I called the oil company and had a nice chat with them, actually learned quite a bit.  I opted to run the oil ratio suggested for the oil.  Slightly less oil than my engine manufacturer, but morethan what other riders suggest.

Between the low flashpoint, quality oil at a good ratio everything seems good.

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4 hours ago, midlife said:

Are these  5-6L cans plastic or metal .Because petrol starts to loose its kick if kept in a plastic can for more than a week ,but in a metal can it stays fresh.

 

Aspen fuel is sold in plastic cans, has a 5 year shelf life.  As for the oil question,my standard response is - "Oil is better than no oil"

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6 hours ago, b40rt said:

Have you anything relevant to the topic to add ?  ( I think your last line should read "just because it doesn't make sense, it doesn't make sense )

You're the one who doubted a guys legitimacy in riding trials just because you didn't know 6 litre petrol cans existed! If that already went over your head, I have a feeling adding more would also

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8 minutes ago, faussy said:

You're the one who doubted a guys legitimacy in riding trials just because you didn't know 6 litre petrol cans existed! If that already went over your head, I have a feeling adding more would also

I doubted his legitimacy because he obviously can't back his statement with any facts. Quoting 2 stroke ratios for 6 litre containers, seems as pointless as your comments !

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9 hours ago, midlife said:

Are these  5-6L cans plastic or metal .Because petrol starts to loose its kick if kept in a plastic can for more than a week ,but in a metal can it stays fresh.

 

or vice-versa. In my experience with OUR car petrol (pump gas) it starts smelling bad sooner in a metal container (metal drum, metal fuel tank)

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6 hours ago, cascao said:

Look at "flash point" at oil specs and choose lower ones to avoid oil spoonge at pipe

Motul 510 is going OK for me. Maybe will test the 710 someday. 

I find that even semi synthetic allows spooge to build up in the muffler and the ring grooves gum up. I'm thinking of going to mineral oil, if it is still available

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I’ve ran fully synthetic at 70 to 1 for about the last 15 years in everything i own ie  beta ,Fantic,strimmer ,disc cutter ,chainsaw even my 4 stroke lawnmower and not had a peep of bother from anything .it seems to me the detergent side of oil is the most important bit of it as lubrication part over exceeds all the specs anyway

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It's been my experience that back in the 70's & 80's using leaded fuel and ratios of 25-30/ 1 there was very little build up of muck in the exhaust and basically no deposits on top of the piston or combustion chamber evident during rebuilds. Fast forward to unleaded fuel and the build up of deposits in the exhaust and engine begin to occur. Around 2000 we were using Avgas with great results and little or no deposit build up. As it is difficult to get Avgas here we have been using pump unleaded and the deposits are back and they occur using semi synthetic oil or fully synthetic. I to have been told to use semi synthetic as the fully synthetic is designed for full throttle applications and is not as suitable for trials as the semi - synthetic. I run at 80/1 semi-synthetic and still get grunge in the exhaust and deposits on the piston and combustion chamber. I don't have the technical know-how to back up these results, its just what I have experienced over a number of years. The other thing about the unleaded fuel is that I find it difficult to get good plug readings as well whereas back  in the leaded days this wasn't a problem and I'm talking the same bikes and same jetting 40yrs later.

Cheers Greg

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So we've went backwards. never used to have any bother ,pistons , barrels ran for ever and always seemed to run fine.

Now if you keep a bike a while they fill up with gunge carbs seem to go out of tune all the time there's always oil lying about motors even if you run them lean.

I don't believe any modern oils are made with slow running cold 2t engines in mind and if they have they've not been tested in my back yard.

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12 minutes ago, breagh said:

So we've went backwards. never used to have any bother ,pistons , barrels ran for ever and always seemed to run fine.

Now if you keep a bike a while they fill up with gunge carbs seem to go out of tune all the time there's always oil lying about motors even if you run them lean.

I don't believe any modern oils are made with slow running cold 2t engines in mind and if they have they've not been tested in my back yard.

Modern oil is probably better in old air cooled motors, at least they get hot !

Speaking to a friend who's an excellent mechanic, his only comment was not to use fully synthetic engine oil in NEW engines until the rings have a chance to bed in. Excessive oil consumption due to bore becoming glazed was a problem with Vauxhall's for a time. 

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1 hour ago, b40rt said:

Modern oil is probably better in old air cooled motors, at least they get hot !

Speaking to a friend who's an excellent mechanic, his only comment was not to use fully synthetic engine oil in NEW engines until the rings have a chance to bed in. Excessive oil consumption due to bore becoming glazed was a problem with Vauxhall's for a time. 

With the amount of posts put up on TC about liquid cooled bikes boiling over its just as well they use fully synthetic oils. As for oil hanging about in the exhaust system and clogging eveything up, mineral oil does exactly the same but probably more so as usually there is a higher oil content due to the petrol/oil mix ratio. Brand new engines car, bike, lorry all come with fully synthetic oils and its no wonder that the engine components take for ever to bed in or run in. Certainly a good quality mineral oil be it 2t or 4t would be great to run in with then change to fc

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