Where does the oil get injected on a Yamaha?

bluehammer said:
I've run that Bender injection system. Never had a fault with it. The interesting concept with this system is this: You're sitting on the lake idling with your buddies. The oil in your carb bowls is just that : oil from the pump on the low end of oil metering, thus not having the oil that you would on the midrange or top end. So you line up and take a blast down the lake. The initial mix that you are running on is leaner because of idling. You don't get the heavier oil ratio in the bowls 'til the oil pump puts it in the fuel pump and the fuel pump puts it in the carbs. Now I suppose that the bottom end of the motor has enough oil in it to compensate for the lean oil mixture in the carbs til the correct mixture gets to the motor. But in theory, the concept is better than oil mixed in the fuel pump because the oil directly injected into the carbs is closer to the mix needed for what rpm is now at hand.
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Exactly...I just did'nt want to type that much...lol
 
bluehammer said:
I've run that Bender injection system. Never had a fault with it. The interesting concept with this system is this: You're sitting on the lake idling with your buddies. The oil in your carb bowls is just that : oil from the pump on the low end of oil metering, thus not having the oil that you would on the midrange or top end. So you line up and take a blast down the lake. The initial mix that you are running on is leaner because of idling. You don't get the heavier oil ratio in the bowls 'til the oil pump puts it in the fuel pump and the fuel pump puts it in the carbs. Now I suppose that the bottom end of the motor has enough oil in it to compensate for the lean oil mixture in the carbs til the correct mixture gets to the motor. But in theory, the concept is better than oil mixed in the fuel pump because the oil directly injected into the carbs is closer to the mix needed for what rpm is now at hand.
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I agree that into the intake has more "peace of mind" to it but is "not" really that much different. Remember that the oil pump is a variable stroke unit, it has a short stroke at idle (equaling 50:1 for arguments sake ) at an idle and when you pin it, it still equals 50:1 at WOT. Most people fail to take into acount that the oil delivery and the fuel delivery (flow) both increase and decrease in theory at the same proportion. As long as the engineers did their job correctly (yeah....right) it should be no problem. So in essence, the mixture is always 50:1 no matter where it's located, (line,bowl, intake). That being said, I still prefer the intake injection. Also, I had read somewhere that premix isn't the most effecient way to mix. The motor does not need the same ratio at idle as it does at higher RPM's (even though I've never seen one fail for this reason).

Just my uneducated .02 worth.
 
Well, you could very well be right. For some reason though, I had always thought that at idle the mixture was leaner. So when you do pin it, you really don't have that 50:1 like we think. On the other side of the coin, it should be understood that the oil in the fuel actually displaces fuel when mixed in the fuel pump. Considering this causes me to think that the jetting would actually change to a richer condition if one would go to the direct oil injection. Hmmm....Another can of worms......
 
bluehammer said:
Well, you could very well be right. For some reason though, I had always thought that at idle the mixture was leaner. So when you do pin it, you really don't have that 50:1 like we think. On the other side of the coin, it should be understood that the oil in the fuel actually displaces fuel when mixed in the fuel pump. Considering this causes me to think that the jetting would actually change to a richer condition if one would go to the direct oil injection. Hmmm....Another can of worms......
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This is absolutley true.......running 32:1 in a sled that requires 50:1 will result in a lean fuel mixture. While in real life the extra oil would probably prevent damage and not cause a burn down.

Further food for thought.....On a newer computer controlled car, the oxygen sensors detect oxygen only. SO if any plugs are not firing (you know as a whole, the engine is rich) the O2 sensor reads the extra oxygen and what does it do??? It richens the already rich mixture up.

Not trying to be a smartarse by any means, just some things I've thought about in the past like everyone else.

Remember what a "theory" is.......something that cannot be disproved.......

I will still continue to use my intake injected oil pump, and if it fails, I'll still mix at 40:1......... ;)!
 
in response to waterfoul make sure ignition is off before you pull the engine with the plugs disconnected from the wires. you're ignition system will not appreciate you doing this.
 
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