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What are the downpoints of 20:1 versus 32:1?


night

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I'm going to generalize this statement.

 

Today's oils protect better and burn cleaner, period.

 

Unless you're running crisco in a can...or alcohol, 20:1 is pretty much un-needed.

 

32:1 is just fine for most oils. I try to stay away from 50:1 and 100:1...

I personally run Super M @ 40:1 with 110 Leaded Race Gas...

 

I don't know what details you're looking for exactly...again, this is pretty much a general statement.

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I do now use Amsoil at 50:1 (usually dominator), but for years I ran 100:1 at 80:1 in a RM125 with no issues ever. And a 125 is screaming the whole time you ride it. My buddy has a hopped up Banshee (approx 65HP) that he has alwasy used 80:1 as well (with the 100:1) and again no problems. I feel 20:1 or even 32:1 is overkill. I have a race sled that I run the dominator at 50:1 with no problems as well.

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There are several people that will agree...

However, I've talked to a lot of reputable engine builders...the majority will tell you stay away from more than 50:1...

 

Keep in mind, a lot of people who race redo top ends every few races, or every season.

This is considered normal maintenance...and they do it primarily to keep that "performance edge"...

Of course, if your name is Carmichael, Reed, Stewart...etc., you don't pay for your top ends, oil, etc., and your mechanic does all your maintenance...between heats, motos...etc., with an endless budget...

 

If you do a search here, you will find the majority run 32:1 or 40:1.

Those on alcohol run 24:1 to 32:1...on average.

 

I'm not saying anyone is right or wrong...but I personally like to stay in the flow of "average"...

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There was a whitepaper published by McCullough some time back regarding oil/fuel ratios. They tested fuels mixed 'oil-rich' to the point of plug failure and found that the more oil they used, the more power they got.

 

That was due to the better sealing properties (piston-cylinder) of the higher volumes of oil used.

 

But...balance in all things will likely be a wise choice. Running 16:1 oil/fuel mix is unrealistic for a number of reasons.

 

The higher oil recommendations from manufacturers is generally considered to be a safety valve for them. There are not likely to be oil related failures when you use SO much of it. But, like most everything else made there is room for improvement...especially when the focus of use is narrowed to include a particular type of riding in a particular environment.

 

A 'good' premix oil runs probably around...what...$40 a gallon? There's a good reason to run less of it!

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There are several advantages to running a mix of 20:1 despite the fact that it is a bit overkill. When breaking in a new top end I would suggest running a richer mix. But after u get it broke in 32:1 will do everything u need it too. The first advantage of running 20:1 is that ur rings will last longer for the few extra dollars u spend in oil. But the downside to this is the fact that u will most likely foul more plugs running this rich of a mix. Running this mix of 20:1 u will need hot burning plugs and have to make sure to check ur carbs for oil build up with i rich mixture like this. 32:1 is about the best mixture u can run todays oils are alot better than they used to be. Running 20:1 vs 32:1 is no real difference other than with 32:1 u will foul less plugs and ur carbs wont get gunked up as fast. Other than that the choice on ur premix gas is all up to you. Running 20:1 will save you no more money than 32:1 mix. I run hondas premix at 32:1 and never had a problem with my bike at that ratio. I havent tried to run any richer because of the disadvantages of doing it stated above.

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See....all about opinions...

96drag...I'm not discrediting or putting you down. I'm merely stating my own opinion... :)

 

I've been of the school of mix it how you're going to run it. Heat cycle it 3 times for about 10 minutes or so...and recheck the torque on the cylinders and head.

 

Then...beat it like you stole it.

 

I've seen pictures of pistons in two identical bikes, one broken in as the manual says...easy first tank of gas or so, varying RPMS, richer premix.

The second based on what I've put above.

 

After a season on each motor...the motor broken in by manual specs was starting to get a little bit of blowby past the rings.

 

The other was picture perfect. Same track time, etc.

 

I'll try and dig up the article....it's very interesting...

 

Again, stating my opinion...

 

:cheers::cheers:

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There are several advantages to running a mix of 20:1 despite the fact that it is a bit overkill. When breaking in a new top end I would suggest running a richer mix. But after u get it broke in 32:1 will do everything u need it too. The first advantage of running 20:1 is that ur rings will last longer for the few extra dollars u spend in oil. But the downside to this is the fact that u will most likely foul more plugs running this rich of a mix. Running this mix of 20:1 u will need hot burning plugs and have to make sure to check ur carbs for oil build up with i rich mixture like this. 32:1 is about the best mixture u can run todays oils are alot better than they used to be. Running 20:1 vs 32:1 is no real difference other than with 32:1 u will foul less plugs and ur carbs wont get gunked up as fast. Other than that the choice on ur premix gas is all up to you. Running 20:1 will save you no more money than 32:1 mix. I run hondas premix at 32:1 and never had a problem with my bike at that ratio. I havent tried to run any richer because of the disadvantages of doing it stated above.

 

I would have to disagree w/you on the break in part. I would run a richer fuel/air ratio, but not fuel/oil ratio. You don't cake the 2 stroke oil on when you put together a top end do you?

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i break mine in with 32:1 or a bit richer. with yamalube or any non synthetic oil

 

after 2-3 gal of gas and couple heat cycles i run 927 40:1.

 

works for me.

 

during break in its a mosquito killer but after that its good to go.

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I would have to disagree w/you on the break in part. I would run a richer fuel/air ratio, but not fuel/oil ratio. You don't cake the 2 stroke oil on when you put together a top end do you?

 

 

I do. I coat the pistons, rings, bore, bearings. Infact some shops (at least in the sled world) suggest a small amount of oil (I believ an oz.) done each crankcase side. I have done this and have not, so I am not really sure if it is necessary. It is a good idea to run it a little rich on oil the first tank. On an injection system, it is a general rule to mix the first tank at 100:1 in addition to the mix.

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Ah....to each their own.

 

I put a thin, thin coat of 2 stroke oil on the cylinders to ease the pistons into the cylinders.

I also put a few more drops on all the bearings for the crank and rods as well.

 

IMO...no need to overkill...

 

The deal in the end is...if it works for you...why change?

 

:headbang:

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