RMK Fuel Filter DISSECTED!

[maxitout77]

Ask and you shall receive! After my recent post about replacing my fuel filter and what it did for performance on my sled, many asked about what a stock filter was made of. Well here ya go. 3700 miles when changed. The pictures speak for themselves. I had to tear the paper filter apart to remove it.

Here is the link to my previous thread about my fuel filter.
http://www.snowest.com/forum/showthread.php?t=373929

I for one, will now be replacing my filter yearly.

 

[800poodragon]

Just replaced mine last week as well...flowed 1 1/4oz of fuel in 35 seconds before change and 2 1/4oz of fuel in 35 seconds after changing. My fuel pump was having issues as well and replaced it too....it sounded like a vacuum cleaner it would run so noisy...now quiet like it should be. Sure runs a lot better now

 

[diamonddave]

Just replaced mine last week as well...flowed 1 1/4oz of fuel in 35 seconds before change and 2 1/4oz of fuel in 35 seconds after changing. My fuel pump was having issues as well and replaced it too....it sounded like a vacuum cleaner it would run so noisy...now quiet like it should be. Sure runs a lot better now

Glad to see guys doing this. What year and how many miles was on your sled?

 

[winter4ever]

By the pictures that looks COMPLETELY plugged! I tore one apart after about a thousand miles and it still looked brand new.

 

[800poodragon]

Glad to see guys doing this. What year and how many miles was on your sled?

I have about 2400 miles on it. 2012 pro. I actually changed the filter a year ago in March as well. I tried everything else I could think of as I was getting a top end miss and it would DET. Had a hard time believing the filter would be that bad but it was.

 

[sledneck_03]

I had 4500 miles on my 2008 700 rmk filter and it didnt look that bad when i cut it apart. Man your fuel must be dirty.

 

[geo]

Thanx for the pic.

When I was prepping this fall I figured it would be a paper medium because it is cheapest to build a small micron filter this way. I should have bought a new one at 1700 miles but it is stupid expensive up here and was not in stock anyway lol.

I wanted to check though, so I set up a reverse flow flush with gasoline, a 13 psi fuel pump I had from a old VW van and a Melita coffee filter lol. This NOT safe in the correct political language today lol but I`m too old to know.

I was surprised at the sediment in the filter. Not a lot because of the size of filter but I use jerry cans I fill up once a week so I don`t have to drive back into town and to do my premix then fill the sled through a filtered transfer pump. I expected to see zilch lol.

I think part of it is the oil I use and part of it is the fuel I can get today. By next season I will have a larger volume auto filter I can toss every year.

P.S. I was just thinking after I stopped typing lol. Lots of room in the Pro`s fuel tank pump opening. Has anyone mounted the filter in the tank to KISS (low pressure side)? Smart valves to screen the big stuff leading to a micron filter before the pump.

 

[mountainhorse]

P.S. I was just thinking after I stopped typing lol. Lots of room in the Pro`s fuel tank pump opening. Has anyone mounted the filter in the tank to KISS (low pressure side)? Smart valves to screen the big stuff leading to a micron filter before the pump.

Not sure that putting a filter, besides the fine mesh built into the smart valve on the suction side of the pump, is a good idea....and would not want to disturb the seals and lines of the PFA (pump/flange assembly) often with out/in cycles to change the filter.

A filter between the smart valves and the inlet on the pump may alter the function of the smart valves.

A larger filter that is more affordable and much easier to change than pulling off all the items, listed below, would have people doing better and more frequent preventive maintenance.

If you could change your fuel filter in 5 minutes for $12... how often would you do it?? ... Compared to $100.00+ and what ends up being over an hour for the average consumer. Dealers get north of $200 to change the fuel filter... OUCH.



Smart valve, like those installed on the suction side of the pump in a RMK.

How they work:
Have you ever sprayed water on a window screen? Recall that the screen will actually hold some of the water. These pickups work the same way. When the pickup is submerged in fuel, the fuel will pass through the mesh with ease. When fuel sloshes away from the pickup, the mesh will hold enough fuel to fill all the tiny holes. That mesh full of fuel acts like a solid. At this point, the pump, sucking on the pickup will cause the mesh to suck shut, preventing the pump from sucking air. When fuel covers the pickup once again, the valve will open up and transfer fuel.

Fuel Filter changing procedure...RIDICULOUS (cost and difficulty/time), IMO.

Fuel Filter - DC-CFI-2 Models
1. The fuel filter should be replaced as outlined in the
periodic maintenance table.
2. Open the left and right door panels. Remove the hood
and drive belt.
3. Disengage the rubber strap securing the oil tank to the
clutch cover. Remove the oil tank mount screw.
4. Remove the two harness connectors from the ECU.
Remove the oil tank fill cap, and then the ECU bracket.
5. Remove the four nuts that mount the clutch cover to
the chassis. Slide the oil tank down to open access to
the two rear nuts.
6. Carefully release the clutch cover from the studs and
then pull it away from the airbox.
7. Depressurize the fuel system. Remove the filter from
the airbox bracket. Disconnect the fuel supply hose
from the fuel pump flange using a disconnect tool.
8. Remove the bottom fuel fitting clamp on the fuel rail.
9. Carefully remove the fuel hose fitting from the fuel rail.
Have a clean shop rag at hand to absorb any fuel that
leaks from the fitting. Dispose of rag properly when
finished
10. Drain any fuel in the hoses/filter into an appropriate
container, and then discard filter in accordance with
local rules and regulations.
11. Apply a light film of two stroke engine oil to the new
fuel supply hose fitting. Carefully install the fitting back
into the fuel rail. Torque screw to specification.
12. Reconnect the supply hose to the fuel pump flange.
Verify an audible “click” is heard and the connections
are secure by firmly pulling on the two hose
connections. Push the filter cartridge back into the
bracket.
13. Inspect the hoses making sure none are worn or
damaged.
14. Reinstall the clutch cover. Torque cover nuts to
specification.
15. Reconnect the ECU wiring harness connectors.
16. Install the ECU bracket onto the oil tank. Reinstall the
oil tank. Torque mount screw to specification.
17. Reinstall the drive belt. Replace the hood and door
panels.

 

[geo]

Agree with all points especially the crazy cost.

 

[mike_s]

Trouble with having a full blown filter on the suction side of a fuel pump is that pumps do not pull well at all. A slightly restricted filter on the suction of a pump will kill the pump far more quickly than that same restriction on the discharge side of the pump. Not to mention the formation of air in the line because of the higher vacuum pressure. Cavitation would also be an issue due to restricted suction. If you wanted to install a filter in the return line to the tank to "polish" your fuel, i dont see that being a bad idea, but a small micron rated filter on the pump inlet is a bad idea. Just stick to the screen/smart valves.

 

[ProRMK24]

Looking at that makes it hard to blame it on the gas....

 

[geo]

Trouble with having a full blown filter on the suction side of a fuel pump is that pumps do not pull well at all. A slightly restricted filter on the suction of a pump will kill the pump far more quickly than that same restriction on the discharge side of the pump. Not to mention the formation of air in the line because of the higher vacuum pressure. Cavitation would also be an issue due to restricted suction. If you wanted to install a filter in the return line to the tank to "polish" your fuel, i dont see that being a bad idea, but a small micron rated filter on the pump inlet is a bad idea. Just stick to the screen/smart valves.

Your right. Thought about on the drive home. Dumb idea to make the pump work harder than it has to and no protection from pump wear or failure.

Oh well. sometimes thinking backwards is backwards lol.

 

[Lachoneus]

what is the solution?

I've been out of these forums for a few years after "converting" to snowbikes, BUT I do still have my '11 Pro 800 and my guess is I've got original filter on it still. Would somebody please post the best "fix" for this? (Procedure for removing filter and part #/source for cheaper/larger aftermarket filter, it sounds like that's what many are doing?). Many thanks.

 

[Lachoneus]

sorry nevermind

Mountainhorse has it WELL covered, just saw that thread, thanks.

 

[volcano buster]

About 1000 miles.

I used the bench grinder to cut the pinch seam around the center of the filter. This kept all extra metal filings out of the filter so I could see what might be in there.

As you can see, pretty clean.

 

[polarcat39]

Great info in this post. Thanks for the picture.

 

[yzviper366]

How is the fuel system depressureized?

 

[volcano buster]

There should be a Schraeder valve on the hard line somewhere close to the filter. If it has been run recently, burp the valve like an inner tube valve, otherwise, I think the pressure dissipates over time if it hasn't been run.

 

[gunnerthesnowman]

I did the auto filter change 1.5 years ago , changing it out now , will cut it open to take a look .
I run the Vipec ECU , i added a pressure senser that i connected to the exhaust pipe to log pipe back pressure , going to do the same thing to the fuel system , would be nice to data log fuel pressure , warns of fuel filter and / or fuel pump problems.
I know when i got my engine /turbo Vipec fuel system from OSP and was setting / tuning , it started acting up and falling off , looked at the data log and i notice the fuel pressure was falling off as boost was climbing , checked and the fuel filter screen was plugged , install new screen ( you can clean them , but this one was so plugged it bent it , plugged with aluminum from the surge tank construction )

 

[slash]

after you cut one in two blow through the hose mine was restricted inside dia was less than 1/8 in AV gas causes a reaction to the plastic in the hose .