661 Oil Test 32:1 vs 40:1 vs 50:1 ?

[KG441c]

What transfers heat out of the topend? The fuel or the oil that migrated to the topend?

 

[Pud]

Airflow

 

[KG441c]

Airflow

So what purpose does excess oil in the topend serve?

 

[bwalker]

Wouldnt a plug check only tell what was goin on in the topend? What about the bottomend? Oil is for the bottomend. What about a 4 stroke ? It doesnt need oil in the topend only on the valves? Imo too much oil in the topend of a 2 stroke is drowning the combustion process

Plug checks as mentioned in the responses to Redbull tell you nothing.

 

[bwalker]

What transfers heat out of the topend? The fuel or the oil that migrated to the topend?

Fuel and oil being evaporated as required for combustion both remove heat out of the motor. Heat is also transfered out of the piston through the oil film and into the cylinder where forced air cools it.

 

[KG441c]

Airflow

I agree. Imo an oil that doesnt soak the topend and retain heat on clean metal isnt what we need. An oil that leaves ample oil in the bottom end but burns off in the topend and leaves a thin hard carbon across the top of the piston will be better because the carbon will act as an insulator and keep the piston from absorbing as much heat and will let the fuel and airflow carry the heat out the exhaust better

 

[Trx250r180]

I am going to sell all my saws ,this is too confusing .

 

[bwalker]

I agree. Imo an oil that doesnt soak the topend and retain heat on clean metal isnt what we need. An oil that leaves ample oil in the bottom end but burns off in the topend and leaves a thin hard carbon across the top of the piston will be better because the carbon will act as an insulator and keep the piston from absorbing as much heat and will let the fuel and airflow carry the heat out the exhaust better

If you have clean metal you are very rich on your tuning. A piston crown and exhaust port soaked in oil indicates rich carb settings and doesn't say much about the oil..

 

[Moparmyway]

I am going to sell all my saws ,this is too confusing .

This is the inevetible conclusion we all must face ..............

 

[Moparmyway]

If you have clean metal you are very rich on your tuning. A piston crown and exhaust port soaked in oil indicates rich carb settings and doesn't say much about the oil..

How are you lumping oil quality in with the state of tune from the carb ?
ie ............ wet piston top =fat fuel mixture (according to you)
Where does the oil quality have anything to do with it ?

 

[Trx250r180]

I mixed up some yamalube last night ,if i have some time this weekend i will see if i like it better then the dumonde stuff ,is wayyyyyy cheaper to buy ,and has color in the fuel to tell it is mixed ,the dumonde is gold ,looks like pure gas in the tank .

 

[bwalker]

How are you lumping oil quality in with the state of tune from the carb ?
ie ............ wet piston top =fat fuel mixture (according to you)
Where does the oil quality have anything to do with it ?

Because a wet, bare metal piston top
is indicative of overly rich and thus cool combustion.

 

[KG441c]

How are you lumping oil quality in with the state of tune from the carb ?
ie ............ wet piston top =fat fuel mixture (according to you)
Where does the oil quality have anything to do with it ?

Some oils combuste better and burn off better than other imo

 

[Trx250r180]

Because a wet, bare metal piston top
is indicative of overly rich and thus cool combustion.

Wont this make the saw last longer ? At a power sacrifice .

 

[KG441c]

Here would be a good test. A bare clean piston saw ran with x oil at x ratio and a piston with carbon on the top with same oil and ratio and check temps

 

[bwalker]

Some oils combuste better and burn off better than other imo

True, but if your both wet and have bare metal, that's rich tuning.

 

[KG441c]

True, but if your both wet and have bare metal, that's rich tuning.

I agree. I believe carbon with proper tuning is normal

 

[Moparmyway]

If you have clean metal you are very rich on your tuning. A piston crown and exhaust port soaked in oil indicates rich carb settings and doesn't say much about the oil..

How are you lumping oil quality in with the state of tune from the carb ?
ie ............ wet piston top =fat fuel mixture (according to you)
Where does the oil quality have anything to do with it ?

Because a wet, bare metal piston top
is indicative of overly rich and thus cool combustion.

Still no explanation how it ties into oil quality

 

[rogue661]

I'll bite I can't believe this is still going! haha ....
I can throw a spanner in the works got a few 066/660 actual work saws some pushing well over 10+ years and never had the barrels pulled to check how clean the top of the piston is or how much oil is in the bottom end?(only pull em down if they end up way down the line as a parts saw) even though some here seem to pull the barrel after 2 tanks of fuel saying all looks good or I'm not happy after 2 tanks? with whatever oil haha...
Well the spanner is? we only use mineral based oil at bout 25:1! I know I know is crazy talk and most likely impossible!, now don't shoot the messenger but never have/seen a saw size or down on power running mineral oil at 25:1 more like up on power seeing a few youtube vids and bets me what the go is with that? ...But yeah mountains out of molehills is more like what is going on here!...
That is unless the only way you can tell your chain is dull is when you see dust? does anyone actually use that as an indicator of how dull a chain is? if true well in that case run the best synthetic oil you can and blame Obama when the piston still smears itself up and down the bore lol.......Just my 2c

 

[bwalker]

Wont this make the saw last longer ? At a power sacrifice .

Hard to say, but could have the opposite effect.

Still no explanation how it ties into oil quality

It doesnt, unless you are tuned right and have carbon on the crown, but are still slathering oil out the exhaust.