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quote:
What is the ratio equivalent of 3%? 30:1 ?
Larry
Larry,
This is a quote from a trials forum on oil ratios.
"So why take the risk of trying something that is so risky ? It ain’t risky Dude. It’s proven. And here is the good part. Your bike will perform better. Some people think that the oil in a 2 stroke reduces the horsepower output. They think that if you put in less oil , then the engine is getting more gas. No way Hosea. Getting more fuel in is easy. If you want to make more power, put in more air. Savvy tuners, especially road race tuners know that less oil means less power for a 2 stroke. I have seen dyno results at different ratios using the same fuel, oil, and engine. Only the oil ratio was changed. The difference on a 125 road race engine was several horsepower . 16:1 gave the maximum power. It seems that in addition to keeping everything sliding and rolling, 2 stroke oil also helps engine sealing. Although the oil helps the piston rings seal, people often forget that everything is critical in a 2 stroke and there are areas below the rings that need sealing too. This was in a road race engine. In a trials engine the difference will be much less. Did you ever see a trials bike tuned for maximum horsepower? Nope. We value low end power and smooth predictable throttle response. Guys that run a low oil ratios may find that in some situations, oil may pool in their bottom end. Well maybe not in their bottom end , but for sure in their engine’s. They get it the worst when descending a long hill with the throttle off. The oil from the cylinder walls and bearings collects in the crankcase. Since it is not getting blown through with the charge ( no throttle = no charge ), it just builds up there until he reaches that log or ditch at the bottom. He gives the throttle a tug and instead of a blip, he gets a blub. Blips are good. Blubs can get you hurt. What happened? He just fed his spark plug a big slug of oil. It also totally messed up his fuel air ratio momentarily. This also happens to a lesser degree at many parts of a some sections."

The whole article is at http://www.trialscentral.com/cms/showarticle.php?articleID=91

FC
 

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Frank,
That quote was kind of confusing to me. At one point he says more oil means more power....then another place that "low" ratios cause oil to gather in the crankcase....so what's better? More or less?

The reason I ask is I just got this Hodaka two stroke, the cap on the fuel tank says, 20:1, the manual says 16:1, the Hodaka forum guys say 40:1....maybe 50:1. The Amzoil two stroke oil I have says 50:1. I was so confused I'm running about 35:1 right now just to average all the input I've gotten.
It's a single cylinder, piston port engine. The Hodaka guys say the old 20:1 ratio was before the use of new and better modern 2 stroke oils...that the 20:1 ratio was back when people were just dumping in any old kind of motor oil.
What would you run in an old dirt bike like this?

Thanks,
JohnnyB
 

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That article made a lot of sense. If you're using high revs, use a 20:1 ratio. If you're idling around, you might want to use a higher ratio to prevent the engine from loading up with oil.

It all depends on how you're using the engine. Just remember that a 20:1 ratio requires bigger jets than a 30:1 ratio.
24:1 is a nice even number.
 

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quote:
Frank,
That quote was kind of confusing to me. At one point he says more oil means more power....then another place that "low" ratios cause oil to gather in the crankcase....so what's better? More or less?
Thanks,
JohnnyB
JB,
If you read the whole article you will understand what he's talking about. A trials bike never uses high revs and needs to run clean after rolling down inclines with no throttle which will tend to load up the motor. If you only run at an idle a 2smoke would probably be happy with 100:1.

FC (The only exception is Johnny Bravo's TA125. He should run at 300:1 with olive oil.)
 

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Frank,

I'm running 22:1 and I use peanut oil. That was Bob Coys suggestion.

I need to find a good oil as the yamalube gets poopy in the wet. Everybody seems to have there own opinion on what brand to use.
Silkolene,Spectro,Castrol,Mobil1, etc

Champ
 

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Thanks guys, that clears things up.
So basically...within reason....the harder you ride, the more oil you need in the premix.
Thanks,
JohnnyB
 

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quote:
Thanks guys, that clears things up.
So basically...within reason....the harder you ride, the more oil you need in the premix.
Thanks,
JohnnyB
Pretty much except when it comes to synthetics. Modern 2 stroke synthetics are much more efficient than conventional 2 smoke oil, and a million times better than what was run back in the day. So I guess my point is when you run a synthetic ou don't need to add in as much as you would a conventional oil.

Personally I use klotz, which smells like 2 stroke oil should and doesn't pop. Also make sure you use oil specifically for your setup: don't use injector oil in premix setups and vice versa.
 

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I love Klotz Oil back in the day when i pre mixed my RD350 i would haul butt down a street only to hook a U turn so i could smell the exhaust .
When I get my T-500 on the road I plan on running Klotz in it .
I use to do trials with my TY250 i pre mixed 50:1
for the above stated reasons.

84 FJ110
77 CB50 Cafe bike now
76 parts bike
74 Suzuki t500 soon to be on the road
 
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