Premix in a four stroke

just James
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just James
Edited Date/Time 8/15/2014 5:36am
Many years ago when I was racing drag bikes, I would always put a small amount of 2 stroke oil in my gas. My theory was that it would help with ring and valve sealing, as well as a little extra lubrication of the pistons and valve stems. I never measured out an exact amount, but I would guess it was about 200:1 ratio. I do not know if it really made any difference, but I do know that my bikes ran very strong for what they were, and the modifications I had done to them. Any of you guys ever try this?
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JA946
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JA946 8/14/2014 10:46am
8/14/2014 10:46am Edited Date/Time 8/14/2014 10:46am
It's why I run leaded gas. I know in drag racing a "top end lube" is VERY popular. Either a little marval mystery oil or some full synthetic light weight stuff.

It can't hurt, especially that heavily diluted.

It's also hard on spark plugs, and can cause cylinder wash if too much is added.

I'm not a chem engineer, but I think a solid leaded gas provides the same benefits.
newmann
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newmann 8/14/2014 11:33am
8/14/2014 11:33am
My Honda generator runs on a steady diet of old stale 2 stroke premix, mystery gas and anything else that I am unsure of. VP race fuel that has turned milky white with floaties in it from all of our humidity is good to go. Damn 13 hp GX390 engine is the real meaning of 4 stroke worthiness.
rosebud441
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rosebud441 8/14/2014 11:39am
8/14/2014 11:39am
Me too, my pressure washer, weedwacker and mower all get a left over cocktail of quality mixed non-ethenol fuel..

My mower has started on first pull for years and years and even more years
Darryl916
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Darryl916 8/14/2014 11:49am
8/14/2014 11:49am
My experience is the same as above. My lawn mower, pressure washer, generator, etc have all eaten my old pre-mix and remained reliable. I run leaded fuel in the 450 for the purpose of valve train cushion/lubrication and it's free of ethanol.

The Shop

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Torco1
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Torco1 8/14/2014 1:06pm
8/14/2014 1:06pm
Like JA946 said, it's almost like using a top end lube. By doing that it helps to keep the cylinder walls lubricated when the piston is on the up stroke.
huck
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huck 8/14/2014 1:09pm
8/14/2014 1:09pm
You should use Rotella. Heck it's the miracle oil. I even cook with it!

resetjet
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resetjet 8/14/2014 5:35pm
8/14/2014 5:35pm
Run plenty of 2 stroke oil in 4 stroke bikes and mowers....Full synthetic 40:1 with no issues.
LappedU
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LappedU 8/14/2014 5:55pm
8/14/2014 5:55pm
we want it in all of our thumper pit bikes and they ran better and smelled better!
4stroke4DWIN
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4stroke4DWIN 8/14/2014 6:05pm
8/14/2014 6:05pm
My pressure washer has had some nasty ass premix and fuel so old it turned to varnish Laughing ran thru it for yrs. Still runs like a champ.Smile
dynohut
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dynohut 8/14/2014 6:59pm
8/14/2014 6:59pm
My Lawn looks GREAT! I dump only a 32:1 motul 800 2T leaded race fuel mix in the tank of my mower and sniff like a basset hound every time I mow the yard! When me and one of my kiddos load up to ride at Lakewood, or Milliken after work and they are low on fuel for there 250F fart bikes I top the tanks off with my YZ144 race blend and we soon get after it! Four strokes are stupid, just like the honey badger....they dont give a shit!
enketchum
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enketchum 8/14/2014 7:07pm
8/14/2014 7:07pm
Oil is fine in anything without a catalytic converter.
Motoxtombo
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Motoxtombo 8/14/2014 7:14pm
8/14/2014 7:14pm Edited Date/Time 8/14/2014 7:15pm
A friend of mine adds some premix oil into the fuel for his kids Kawi 250F bikes,I'm not sure how much he puts in but he says it helps the top end.
RandyS
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RandyS 8/14/2014 7:23pm
8/14/2014 7:23pm
The problem with 4 strokes is that it's too easy to dump your extra gas in the truck at the end of the weekend. There's never any left for the mower.
hillbilly
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hillbilly 8/14/2014 8:07pm
8/14/2014 8:07pm
The oil drops the octane of the fuel .The 4str of today are borderline on high grade pump gas .

Adding oil could easily cause preignition and you wont be able to hear or feel it most likely.

It is fine to put premix in generators and weedeaters,they are about 8:1 compression ratio.

Most Fs claim 12:1 and high grade pumps gas aint what is used to be.
JA946
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JA946 8/14/2014 8:11pm
8/14/2014 8:11pm
enketchum wrote:
Oil is fine in anything without a catalytic converter.
When gas was more than two weeks sitting, I'd dump it in my truck. Catalytic converter is just fine after 150K.
JA946
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JA946 8/14/2014 8:12pm
8/14/2014 8:12pm
hillbilly wrote:
The oil drops the octane of the fuel .The 4str of today are borderline on high grade pump gas . Adding oil could easily cause preignition...
The oil drops the octane of the fuel .The 4str of today are borderline on high grade pump gas .

Adding oil could easily cause preignition and you wont be able to hear or feel it most likely.

It is fine to put premix in generators and weedeaters,they are about 8:1 compression ratio.

Most Fs claim 12:1 and high grade pumps gas aint what is used to be.
People run pump gas in modern dirt bikes?

Why?
The Rock
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The Rock 8/14/2014 8:39pm
8/14/2014 8:39pm
enketchum wrote:
Oil is fine in anything without a catalytic converter.
JA946 wrote:
When gas was more than two weeks sitting, I'd dump it in my truck. Catalytic converter is just fine after 150K.
Did the title just change? Smile

Pit Row

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hillbilly
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hillbilly 8/15/2014 5:27am
8/15/2014 5:27am
hillbilly wrote:
The oil drops the octane of the fuel .The 4str of today are borderline on high grade pump gas . Adding oil could easily cause preignition...
The oil drops the octane of the fuel .The 4str of today are borderline on high grade pump gas .

Adding oil could easily cause preignition and you wont be able to hear or feel it most likely.

It is fine to put premix in generators and weedeaters,they are about 8:1 compression ratio.

Most Fs claim 12:1 and high grade pumps gas aint what is used to be.
JA946 wrote:
People run pump gas in modern dirt bikes?

Why?
Dunno,

If they realy are 12 to 1 ,my 08 crf claimed 12.5 to 1 I think, then pump gas should detonate in extreme conditions.

It may be that the volumetric efficiency of the cylinder head is 80% or so and the 12 to 1 compression ratio is at idle and very low rpm.

At high rpm the ratio could be 9 to 1.

If that's the case a port grind would pick up a lot of power.
Crush
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Crush 8/15/2014 5:36am
8/15/2014 5:36am
I was actually googling what to do with old premix the other day since I sold my two stroke... Seems lots of people run it through their cars just diluted a bit...

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