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Random question...

I've always been taught that blipping the throttle helps a two stroke engine somehow. Someone was telling me yesterday how it's terrible to do that though. Why or why not?
 

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It may keep the engine from loading up with fuel. It also can keep the RPM's up enough to keep the belt engaged, like when you are descending a steep hill. I know some very talented mountain riders that are always blipping the throttle, it seems to help them maintain control as they take on a technical line along a sidehill. When the engine is at low RPM, there is very little torque available, so blipping can keep the engine RPM high enough that when the power is instantly needed, it's there instead of having to wait for the engine to rev into the powerband.

But if the clutch is engaging and disengaging when the throttle is blipped, that will wear out the primary spring more frequently. That probably isn't a concern for most, though. And I bet some folks just do it out of habit.
 

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I have always blipped the throttle especially to warm the engine!
I have Never started a 2 stroke and just let it sit at idle to warm up!
If there is something in your fuel, the pilot jet will find it, that can and will ruin an engine!
 

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I never blip the throttle, always viewed it entirely different from BC_Dan and kccats. Just figured it was a fad, like wanting to pop wheelies.
 

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I think that is a bit different. I'm thinking more about the guys that think the throttle is a game controller and they need to press it rapidly to be "cool"

KC, not sure how blipping the throttle would save anything from debris. I'd rather have the pilot get the debris than the main jet, where it would lean out the motor at higher RPM.
 

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SummitSpeedFly
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Random question...

I've always been taught that blipping the throttle helps a two stroke engine somehow. Someone was telling me yesterday how it's terrible to do that though. Why or why not?
A valid reason to "blip" the throttle is to lubricate the engine on downhill runs. When the clutch is properly engaged (back-shifted) on a downhill pitch, the engine RPMs will increase (providing engine braking), but there will be no fuel-oil mix entering the cylinders and engine case, as the throttle is closed. Whether you pre-mix, or have oil injection, it is critical to occasionally introduce fuel/oil for cooling and lubrication. The oil injection pump is not RPM dependent, but instead is throttle position dependent. No throttle = no lubrication. 2-stroke dirt-bikes work the same. I can't see any reason that other blipping techniques can do any harm to an engine.
 

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Unless that down hill run last 5 minutes or more, I doubt it would really make much of a difference on the oiling.

But like Dan said, it keeps the clutch engaged.
 

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SummitSpeedFly
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Unless that down hill run last 5 minutes or more, I doubt it would really make much of a difference on the oiling.

But like Dan said, it keeps the clutch engaged.
So, you'd run your engine, any engine, at 5000+ RPM for 5 minutes with NO lubrication? On a 2-stroke, there is virtually ZERO lubrication occurring if there isn't fuel/oil mix running through it. No top end, no bottom end, no lube, running dry. It's not like there will be any residual lube anywhere, until you pump some in with the throttle. I've seen many a 2-stroke dirt bike destroyed like this.
 

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I guess I've never hauled butt down a mountain that would make my engine go 5000 rpm without me applying throttle in the first place.

At idle, you are pumping oil into the system. Higher RPM also has more pressure, which also results in a little bit more oil being pushed through.

Now, there should be a note about which type of motor we're talking about. The most common is oil injected with the flow controlled by the throttle position. On carb'd machines, the ratio is typically around 40:1 at idle and leaning out slightly as the lever goes up. I can only speak to most Skidoos, which went from 40:1 to 55:1.

The amount of oil difference is very small, so even when the motor is free-wheeling and no throttle is applied, it is still getting the oil that it would normally get at idle, plus a slightly bit more due to the pressure of the pump turning a higher RPM.
 
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On Polaris oil pumps, idle is probably about 100:1 with WOT at about 40:1. And the faster the engine turns, the higher the oil pressure, which will give more oil. Plus, any oil that is injected heading down a long hill with the throttle closed won't be diluted with gasoline, so it stays in the engine instead of being washed off with fuel. Oil and fuel are delivered separately and independently to the intake, so even if there's no fuel coming in, there is still oil. That would not be the case with pre-mix engines, I can see where that could be an issue.

I have not heard of anyone that has had oil-starving issues due to high RPM/low throttle, especially while descending down a long hill. But when heading down those big hills, no one has the throttle at continuous idle, you have to keep revving the engine to keep the belt engaged to help maintain control. Trying to use only the brake when descending to keep speeds safe often results in loss of control as the track will lock up and gravity steers you. I always find it interesting learning about different experiences in different areas. Good discussion!
 

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My sleds will roll 70 mph at barely 1/4 throttle on railroad bed trails. That is very little oil being sipped mile after mile. I give mine a blip from time to time to give it some oil. This is my theory on why Polaris 550's burn down. They are already set up very lean on gas and oil. Riding mile after mile at a steady light throttle (wife) makes them too lean too long. Drive like a granny if you want to but I will keep pumping the oil.
 

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easy fix to add more oil if you think the machine is lean on oil, just adjust the oil lever. If I thought that was the cause of the motor burn down, I'd definitely adjust it to dump a little more oil.
 

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Much easier to just blip the lever!
I have never just ran a steady 1/4 throttle!
I am always up and down!
I have told EVERYONE who has ever ridden any of my Big Cats
Hold the throttle wide open for only 3 seconds and let off You are doing 100!
 
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