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CFI-4 Oil injection delete

In the end of last season the oil pump failed on my D8, resulting in a seized engine. The funny thing is that I always have run 100:1 premix beside the oil injection ever since I replaced my pistons last season (1200 km). But the oil consumption was fairly high from the pump (32:1-ish) which generated a lot of smoke with the added premix. On the last ride I topped up the oil reservoir and skipped the premix. The smoke was gone and the engine ran cleaner, but after about 50 km the engine seized. When checking the oil reservoir I discovered that it was still full. I don't know yet if the oil pump has failed or that air somehow has found it's way into the oil lines, but I know for sure that the engine did not receive any oil.

800-dragon-rmk-155.jpg


Now when I'm doing the rebuild I would rather go premix only, and here is why:
- I can never rely on the oil pump alone and have to premix to some degree anyway.
- I will know exactly the amount of oil that goes through my engine at all times.
- I always fuel up from jugs anyway because of my riding situation.
- Removing the oil injection system will result in a lighter sled.
- I will gain more room under the hood (I am currently modifying the sled to make it lighter, narrower and more nimble)
- I can compensate for the possible leaning effect the premix has since I run with a PC5.

It feels like it quite straight forward with the 4 injector system, where the lower injectors can supply the crank with oil. I've tried to find information on this on the web, but I can't find a good answer. I know the outer bearings on the crankshaft can't get oil without injection in stock form, but there must be a workaround for that since the IQR doesn't need injection.

POL-800-Engine-Side.jpg


Please pitch in with your thoughts, pros and cons. Is it possible to do an oil injection delete on the CFI-4 800? If not, why? And if yes then how?
(I apologize for the grammar, I am from Sweden).
 
Last edited:
L
Sep 6, 2011
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Is it possible to do a oil injection delete? Well anything is possible, but I have never heard of someone doing it successfully. Would I myself? never.

Like you said, the lower fuel injector is not always on, so you will be running with out any oil going into your crank case. When did the IQRs get fuel injection? I have not been following along with the new IQRs.
 

sledhed

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Oil pump failures in recent history are very rare... not reassuring when you are the one who had the failure though. Same basic design from the late 90's on, most made by Mikuni if I recall, many high mile sleds without a hiccup. Had a friend with an 08 Dragon whose oil pump was pumping too much oil like yours was and he fought it for a couple seasons at least, finally replaced the pump and all was good, but since it was over-pumping that may have led to early failure in your case, just speculating, but it is possible if you had addressed that issue early on it would have prevented the failure...
 
Is it possible to do a oil injection delete? Well anything is possible, but I have never heard of someone doing it successfully. Would I myself? never.

Like you said, the lower fuel injector is not always on, so you will be running with out any oil going into your crank case. When did the IQRs get fuel injection? I have not been following along with the new IQRs.

This is an interesting part, does anyone know in which RPM window the lower injectors are on?

I am curious about this to, does the new IQR with fuel injection also have oil injection?
 
The oil pump is needed to feed the outer crank bearings from the extremities.
Yes, this is a problem. But since the IQR has the same engine design and works without oil injection I wondered what the difference is?
I figured there must be drilled oil ports somewhere from the crank case to the outer bearings, or is there some type of seal and a grease zerk?

Fun fact:
The 2009-2010 IQR has the same bearing on the PTO side (3514587) as my sled.
All models (800 and 600, including IQR) has the same bearing on the MAG side (3514499) as my sled.

Oil pump failures in recent history are very rare... not reassuring when you are the one who had the failure though. Same basic design from the late 90's on, most made by Mikuni if I recall, many high mile sleds without a hiccup. Had a friend with an 08 Dragon whose oil pump was pumping too much oil like yours was and he fought it for a couple seasons at least, finally replaced the pump and all was good, but since it was over-pumping that may have led to early failure in your case, just speculating, but it is possible if you had addressed that issue early on it would have prevented the failure...
That is what I have heard also, and I do not know yet if my oil pump has failed, but I have never heard of a failure resulting it to pump too much oil, not saying that I do not believe it, I have just never heard about it. I would be interesting to hear if anyone else can confirm what in the pump fails if oil consumption gets abnormally high.

Since I will have do go premix to some degree from now on for peace of mind I figured I could just get rid of the oil injection all together, if it is possible.
 
L
Sep 6, 2011
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The difference is the IQR is carbureted with fuel and oil always going through the bottom end. The CFI engines do not have fuel going through the bottom end at all times. So if you premix, there will be times when your bottom end is not getting any oil.
 
The difference is the IQR is carbureted with fuel and oil always going through the bottom end. The CFI engines do not have fuel going through the bottom end at all times. So if you premix, there will be times when your bottom end is not getting any oil.

True, but does anyone know how the 2009 CFI4 800 fuel injectors operate? I've heard that the ECU switches between injectors and that they are not supposed to operate at the same time, but I am not sure which ones are used when and at which RPM/throttle position they switch.

Would it theoretically be possible to use the PC5 to add fuel at the lower injectors at all conditions where they normally are not in use and remove the same amount of fuel for the upper ones? Wouldn't this ensure lubrication to the bottom end at all conditions?
 
It is not possible to do an oil injection delete on this motor .
If was never designed to do this.
Buy a used oil pump and be happy.

Since the IQR engine is made by the same company I can't imagine that the design can be that much different, but they have obviously made something different to ensure lubrication of the outer crank bearings and the water pump shaft. One thing is the slit in the right center bearing seat seen in the picture below, which I assume is to lube the water pump gear.
DSC06812.jpg


I plan to solve this in the same way as JHG did it with the AC 1000 in The Oil Delete Thread, where he drilled a hole beneath the crank and installed a line between the crank case and water pump gear. The brass fitting connected to the hose is a one way valve which only allows fluid to travel from the case to the water pump shaft.
P1010153-1.jpg

The check valve obviously has a different location on the Polaris, but the principle is the same.

I haven't found out the difference with the outer bearings between the IQR and the injected sleds, does anyone know how they solved it? Is the PTO side outer crank bearing still greased?
 

retiredpop

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Is it possible to use a crank bearing with iso-flex grease like Skidoo?
But it would be easier and probably cheaper to put in a new pump. I just put a new one in one of our 2010 sleds. The pump went wide open when it failed so it used a ton of oil. It was a bit of a pain to change it cause you have to pull the motor but cost was only $300 Canadian. If you have the motor out then changing it is very simple.
 
I am aware that it is easier and maybe cheaper to install a new oil pump, but that's not what I'm asking for, since I already know how to do that.

I will never rely on an oil pump in this engine again, which forces me to premix anyway. By deleting the oil injection all together I shed weight and make more room in the engine bay, as well as making it more simple to do engine work.

What I want to know is how the IQR engine block is different from the IQ engine block? I hoped there was someone here who is experienced with race engines.
 
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