Very bad internal frame rust!

13 replies to this topic
  • Lheffe

Posted August 21, 2004 - 05:59 PM


Yikes! My '99 WR400F frame is rusting away from the inside out!

I discovered this horror-show during a rear suspension linkage and bearing replacement job. I was also having a slice in the frame (from a rock encounter) welded up on the right side just forward of the footpeg.

Before having it welded, I banged the area with a rubber hammer to loosen anything that might be up in there. Sure enough, TONS of 1/2-3/4 chunks of disintegrated metal fell out! I dislodged enough chunks to fill a ziplock baggie 1/4 of the way full. It's heavy too, so I know it was formerly frame material.

So, I decide to check the area as best I can, and have the rock gash welded up anyway. Low and behold, while sanding and starting the paint touch-up, I discover yet another "rust eruption" poking through the surface. Probing the area with a screwdriver, I find PAPER THIN metal near the swingarm. Uggh. This is becoming a nightmare real fast.

Since it is impossible to determine the extent of the internal rust and subsequent damage to the metal's integrity, I am contemplating just getting a new frame from the factory. This can't be cheap, but what else can I do?

If you've ever noticed how Yamaha builds their thumper frames, check out where the vertical and horizontal tubes meet at the swingarm and footpeg area. Here, the two tubes are mated into the curved section using specially formed sheetmetal.

Any fix suggestions? Does Yamaha or anyone sell a "patch panel" for the frame? I'm not a welder, but it looks like an extremely difficult section to have to re-fabricate.

How could you trust a USED frame section, even it were available? To top it off, how can I be sure the other side of the bike isn't rusting from the inside as well?

By the way, I have never power-washed the bike, and it is maintained very well. I live in Arizona, so there isn't that much water to contend with on the trails. Needless to say, I am not going to be jumping the bike until I figure out what to do...

Thanks for the help/suggestions everyone.

Jeff Lundqust
1999 WR400F
Arizona Trail Riders
AMA #384969

  • RoosterJ

Posted August 21, 2004 - 07:05 PM


Post deleted by RoosterJ

  • Gadsen

Posted August 21, 2004 - 09:15 PM


I'd go to ebay and bid on this one, its from a 426, but I bet it will work. Just make sure you get a title with it, as it has the frame numbers on it, you will technically end up with a 2002 WR426 with a 400 motor when your done. Heck, this would make it work some more too! :thumbsup: Oh, it ends in a little more thna 1 day. Its up to $50 now with a single bid.

  • Hamish

Posted August 22, 2004 - 12:39 AM


rust normally only occours in the lower rails (where the water sits). Ask a chassis guy how much it'd cost to replace the lower rails. The best part about doing it this way is he'll set it up in a jig and you'll have a perfectly strait bike when he's finished.

  • Lheffe

Posted August 22, 2004 - 07:33 AM


Hey everyone.

Thanks a lot for all your comments and advice on my rusty frame dilemma!

For the record, the rust is NOT in the lower tubes. There was some rust where the footpegs connect, but the scary portion that still remains is in the curved, formed sheetmetal section just above where the swingarm pivot bolt goes through. If the rust were only in the lower tubes, then yes, it could be repaired fairly easy with new tube.

I have decided to call Yamaha corporate on Monday to see what they have to say, what's available for repairs and what other frames might be interchangeable.

As we all know, there have been many changes on WR's from '99 to the present, and I would not doubt there are several frame bracket differences. Starting over with used parts (such as on Ebay) presents the same possibility for internal rust that can not be detected from the outside.

For the new frame, I thought about several rust preventative methods:

1. Have the frame coated inside by a professional automobile rustproofing company. Some access holes would have to be drilled, but they could be plugged afterwards.

2. Close the factory drain holes and fill the frame tubes with oil. Obviously some extra weight would added, but I read of one european auto builder who boasted of using an oil filled frame...

I will re-post my findings later on in the week.

Thanks again everyone for your help. TT rocks!

Jeff Lundquist
'99 WR 400F
Arizona Trail Riders
AMA #384969

  • ncmountainman

Posted August 22, 2004 - 08:12 AM


ya i noticed that once the paint comes off the frame rusts up faster than anything i've seen. they say they are made from some new alloy (what is it?) what ever happened to good ol' chrome moly?

  • Lheffe

Posted August 22, 2004 - 02:18 PM


I just got back from my local Yamaha dealer. They want $900 for a new frame. Ouch.

Here is an interesting comment, from the parts counter guy no less. He said that the "drain holes" in the frame are not really drain holes at all. They are there to allow hot air in the frame somewhere to expand. Hmmmm, I'm not sure I'm ready to buy into that statement 100%, how about you lads?

Anyway, my plan is to keep riding the bike for now, but keep a close eye open for stress cracks. I don't race the bike mind you, but I ride for all I'm worth each and every time.

When the opportunity is right, I'll do a complete tear-down and take it to the best frame shop I can find. Hopefully it can be sliced, diced and repaired for less than the cost of new. Then it will be powdercoated and internally rustproofed!

I'm still going to call Yamaha corporate and explain my situation. You never know until you try.


Jeff Lundquist
'99 WR400F
Arizona Trail Riders
AMA #384969

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  • Lheffe

Posted August 24, 2004 - 04:45 PM


Update: 8/24/2004.

My local dealer's service department manager (a friend) just took digital pics of my frame rust and submited them to Yamaha corporate. If all goes well, Yamaha will be sending out a new frame free of charge.

FYI: The new frame would arrive with no VIN number, and the shop would then stamp my VIN into the new frame. The old frame must be destroyed, or Yamaha sometimes asks to have the steering stem (where the VIN is stamped) cut off and sent back to the factory. This is to insure no one else ever reuses the old frame or VIN number.

Right now my fingers are crossed so much they ache. I'm just hoping for a little justice, the angels to sing and Yamaha corporate customer service to help me out with a new frame!

For all you other enthusiasts, I suggest spraying some WD-40 up into your frames through the drain holes. Do it after every wash session. Start doing it now and avoid the major hassle (and downtime) I'm unfortunately going through.

Stay tuned on this continuing saga...


  • Gadsen

Posted August 24, 2004 - 05:59 PM


Thanks again everyone for your help. TT rocks!

Jeff Lundquist
'99 WR 400F
Arizona Trail Riders
AMA #384969

What I'd like to know is how does one live in Arizona and end up with a rusting frame? :thumbsup: :devil: :awww:

  • jchantzWR400F

Posted August 25, 2004 - 01:11 PM


Thanks again everyone for your help. TT rocks!

Jeff Lundquist
'99 WR 400F
Arizona Trail Riders
AMA #384969

What I'd like to know is how does one live in Arizona and end up with a rusting frame? :thumbsup: :devil: :lol:

What I'd like to know, is why corporate Yamaha would give this guy a new frame for his 99 (5 years old), but not perform the 04 starter upgrade for 03 model WR's :awww:

  • Jackazz

Posted August 25, 2004 - 01:23 PM


Possibly because riding an '03 with a crap starter, in it's intended enviroment is'nt potentialy lethal...? :thumbsup:
Posted Image

  • jchantzWR400F

Posted August 26, 2004 - 06:33 AM


Possibly because riding an '03 with a crap starter, in it's intended enviroment is'nt potentialy lethal...? :devil:
Posted Image

Good point. :thumbsup:

  • RoosterJ

Posted August 26, 2004 - 07:58 AM


Post deleted by RoosterJ

  • jchantzWR400F

Posted August 26, 2004 - 08:06 AM


OK dude, we get your point. :thumbsup:


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