Check your Heim bearing housing for wear!!!

During a recent vacation out of state, I was able to go to a local motocross race and noticed several newer style KTM's being raced. I went over and checked each one and alerted the owner on how much the ridge on the mud flap had worn a groove on the Heim bearing housing on the swingarm. One bike was a brand new KTM520 only ridden 3 times and it already had a groove cut into the bearing housing.

Cut a piece of bicycle tub and put it around the Heim bearing housing or go buy a Heim bearing guard protector ( to keep the mud flap from rubbing the housing. It doesn't take long for the abrasive plastic in the mud flap to completely chew through your bearing housing. Its usually the two long ridges that run up and down the mud flag that does the most damage to the back side of the housing.


'01 DRZ400S

'00 KTM250exc

Thanks for the info - I'll check mine tonight!



"01" KTM 520 EXC

Mesa, AZ

Thanks a BUNCH!! for the post. I checked mine this weekened and it was already groving. I took off the mud flap and ground off the one ridge should be ok now.

Thanks again good info



"01" KTM 520 EXC

Mesa, AZ

No problem, glad to help.

I started a campaign now that every time I see a KTM, I stop and alert its owner about the mudflap and the heim bearing housing.


'01 DRZ400S

'00 KTM250exc

I just checked mine and it is getting the wear goove also. Thanks for the post!


01 400 MXC

00 XR400

Mine seems fine but I will keep an eye on it. The flap on my bike (new 01) doesn't have any rough edges on it. I wonder if this is from different molds or something? Maybe KTM has a bogus one at the factory that is causing this....Maybe someone should send them an email.....

Try a piece of Duct Tape on the area that rubs, it works real well and is a cheap fix.

Just noticed today that mine was also starting to get a wear mark....went straight for the duct tape, fixed her up, came here and saw that someone else had also used the all mighty duct tape for a fix......ROCK ON

FYI for the new members

I covered the rear face of the housing in about 3mm of silicone. Works well to stop the rubbing and can hardly be noticed.

[ November 01, 2001: Message edited by: Max ]

Another good tip Max, Thanks.

Does this apply to 2002 models?

I can't find the problem you're describing on my 520 MX/C.


You will see what we are talking about after about 5 or 6 riders. Its the two ridges that go verticle on the rear mudflap that causes the problem. The last 2002 I looked at still had the ridged mupflag which hacksaws the heck out of the heim bearing housing on the side towards the tire.

Bikes with the 19" rear tire are the worst as the mudflap seems to rub on the bearing housing worst.

A easy way to see what we are talkiong about is to push the mudflap against the bearing housing and then push up and down on the seat to make the suspension move.

I see some dealerships are grinding the ridge off while setting up the bike, so maybe yours is already been modified.

[ November 02, 2001: Message edited by: KTM250rm ]

I've noticed the wear as well. It is subtle, but definitely increasing.

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