Warning on std air box and K&N filter

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cobbadiggabuddyblooo
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Warning on std air box and K&N filter

Post by cobbadiggabuddyblooo » Thu Jan 17, 2019 11:42 am

Motivated once again I went into the man cave to finally fit the TDMR40’s I have for the white TRX.
Removed the air box and took off the std CV carbies and the first thing that was apparent is the inlet rubbers. Shot to pieces so into the spares and put on a new pair of genuine rubbers.
Looking into the inlets I was amazed at what I found. I knew the inlet valves had been replaced recently but who ever did the service needs a clip over the ears.
Inlet ports had was partially covered with tiny black balls of a gritty feeling material.
Rod to the rescue and informed me from the photo, has the bike had a foam filter fitted. When they degrade and mix with oil /fumes from the breather you get this same outcome.
But it’s the original airbox and K&N Filter fitted.
So I went back to look at the airbox and found the culprit. The foam fitted around the airbox to seal it under the tank was degrading and falling apart especially under the inlet horn.
Opened the airbox to find how this was getting past the K&N filter.
There are 4 tangs that sit against the air filter to hold it hard against the box to help seat it.
Great for the std plastic framed std air filter but with a flexible K&N rubber frame the centre 2 actual sit the other side and allow air to sneak in under the removable air box horn section that allows you to access the air filter.

So if you have a std trx , check the foam surrounding your airbox. If degrading remove it all. If you have a K&N filter fitted find a way ( maybe a drop of sealant to hold the filter hard against the box in the centre before fitting the horn or lid.
laughter is the best medicine

gavinfdavies
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Joined: Sat May 25, 2019 6:25 pm

Re: Warning on std air box and K&N filter

Post by gavinfdavies » Mon May 27, 2019 3:02 pm

cheers for that info, will check when mine arrives later this week

eds850twin
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Re: Warning on std air box and K&N filter

Post by eds850twin » Wed Sep 16, 2020 10:15 pm

Hi
I recently purchased a new K&N air filter element for my TRX & inc in the box is a tube of K&N sealing grease which you have to apply to the 2 sides on installation & each time you remove the element for cleaning to seal it. This info & grease don't normally get passed on between owners & if you have never purchased a new K&N element then you would never know this. The sealing grease can be found for around £6 a tube on Bay. The fact the foam under the tank is now over 20 years old which is around the right age for modern foam & rubber automotive components to start & fail.
ED

handsomejackuk
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Re: Warning on std air box and K&N filter

Post by handsomejackuk » Wed Sep 23, 2020 10:07 pm

thanks for this i will get the bike out and have a look i have had a k and n filter on mine for about 15 years and during that time its probably been out 3 or 4 times for a check and as you know mine doesnt do many miles if at all.. but worth lookling at i did start the bike about 3 months ago and let it run and give it a quick run around the farm...

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