Air Filter Disaster! Input needed,please.


8 replies to this topic
  • XT2YZ

Posted May 21, 2006 - 06:27 PM

#1

I was riding my '04 YZ450F at a sandy track this weekend. When i got finished I was going to pull the filter and wash it. I took the seat off and it was like my worst nightmare. My filter was sitting in the air box still connected to the sealing ring, which had pulled right out of the intake boot. There was a nice little pile of sand in the boot. I know I rode a few laps after it happened. The bike came down on my boot and the boot went right through the side panel of the air box and pulled the filter cage, still connected to the sealing ring, right out of the boot. So unbeknown to me I was riding around with no filter. Luckily it was moist out so the dust was not bad but there was sand in the intake boot. I didn't notice anything wrong with the way it was running and a few of my friends say it may not be that bad. I would love to believe that but I'm not sure how to assess the damage to see what needs to be done. I have the sub frame off and looking into the intake on the carb you can see that some, not much but some, sand got in there. I have not done anything else yet. I'm thinking change the oil and check the filters for sediment. First thing you do is warm up the bike to change the oil so it all gets out but I don't want to run it if it could make things worse. Any suggestions?

Thanks!

  • Wheel

Posted May 21, 2006 - 07:19 PM

#2

On a 4 stroke motor, all the air flow goes through the filter (at least it is supposed to), the carb, the intake valves, across the top of the piston, and out the exhaust valves. Threfore, you don't have to worry about dirt getting into the bottom end. The biggest concern is going to be the valves and seats. This is where the most damage is caused if a 4-stroke sucks dirt past the filter. If it was mine, I would have a competant engine builder do a valve job. As long as I was that far, I would also probably pull the cylinder and check the cylinder and piston and re-ring it if these both check out. Also disassemble and clean the carb.

  • 02YZ426

Posted May 22, 2006 - 02:23 AM

#3

I had the same thing happen to my YZ250... but I was not as lucky as you. My engine seized up and I had to replace the crank and a whole new top end including the cyclindar :ride: Sound like you may have gotten lucky though. You probably should take the carb off and give her a clean before you try running the bike again.

  • XT2YZ

Posted May 22, 2006 - 05:33 AM

#4

Thanks for the input guys. Is there any way I can tell if I need to replace the valves before tearing into it.Or, is it just a given being the sand got through there?

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  • mkporn

Posted May 22, 2006 - 07:03 AM

#5

It's not a given that the valves will even need to be touched.


Tear down the top end and have a look at the cylinder and piston... Check to see that you dont have a bunch of deep scratches in the cylinder wall. If the jug is fine, leave it, Replace the piston and rings while you are in there. If it is gouged badly, get it replated or sleeved.

As for the head and valves, fill the intake and exhaust side ports with solevent and check to see if it will bleeds past the valve seats and valves. If not you will be fine, if it does, take the valves out and inspect them for damage or debris caught between valve and seat. Clean them up and reinstall. Check again and see if they still leak, if not put it together and ride.... If it leaks badly you will want to take it in and get it fixed. I would guess that you won't have any problems with the valves. :ride:

  • grayracer513

Posted May 22, 2006 - 07:23 AM

#6

There are a number of things you have no way of knowing. First, you don't know just how long the air filter was disconnected, or how much sand went through the top. It is true that the bulk of it would tend to stay above the rings, but as soon as some of it gets caught along the cylinder edges, it will grind on the bore and rings, and that debris will go to the bottom and into the oil.

There are two ways to find out how serious and event this was; run it and see what happens (definitely not advisable), or tear it down and see.

Solvent testing the valves will tell you if they are sealing or not, and IF the clearances are all OK (check as you disassemble), and they pass this test, you might leave them alone. I would tear the head down so I could throughly clean it and examine the valve faces.

With the top end off, fill the engine and oil tank with a 50/50 mixture of shop solvent (mineral spirits) and ATF, spin it and slosh it some and drain it out. then inspect carefully for any trace of sand.

  • XT2YZ

Posted May 22, 2006 - 09:52 AM

#7

Thanks to all:) I am going to start tearing it down to see what I can (or hopefully cannot) find. I'll check the valves and cylinder and go from there.

Thanks again!

  • cleonard

Posted May 22, 2006 - 10:34 AM

#8

Thanks to all:) I am going to start tearing it down to see what I can (or hopefully cannot) find. I'll check the valves and cylinder and go from there.

Thanks again!


It's good to look, for piece on mind if nothing else. Take a close look at everything since it will be apart.

Several years ago, while riding at Pismo beach (sand dunes), I saw that my air box to carb boot had partially come off on my XR500. I only noticed when loading the bike into the truck at the end of the day. I was like, "Oh no I Killed it!" I removed the head and took a look. There was sand everywhere(carb, the rubber carb to engine boot, head, exhaust pipe). The worst was the carb. Much to my surprise there was little damage. I cleaned it good, changed the oil, and the bike ran for several more years.

  • XT2YZ

Posted May 22, 2006 - 10:49 AM

#9

It's good to look, for piece on mind if nothing else. Take a close look at everything since it will be apart.

Several years ago, while riding at Pismo beach (sand dunes), I saw that my air box to carb boot had partially come off on my XR500. I only noticed when loading the bike into the truck at the end of the day. I was like, "Oh no I Killed it!" I removed the head and took a look. There was sand everywhere(carb, the rubber carb to engine boot, head, exhaust pipe). The worst was the carb. Much to my surprise there was little damage. I cleaned it good, changed the oil, and the bike ran for several more years.

Thanks! That makes me feel a little better:) I checked when I took the pipe off for any that might have got through and there was none so hopefully that was a good sign.





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