2003 WR 450 Case Explosion, now what to do?

9 replies to this topic
  • shoremethod

Posted October 13, 2010 - 12:06 PM


I've been an avid reader of this forum and you guys offer great advice, so thanks in advance!

My '03 WR450 recently experienced a backfire on startup that resulted in shreading the kickstarter gears and exploded the main case out the back of the kickstarter assembly.:smirk:

Now that the cussing is over and the blue smoke has cleared I'm stumpped as to how to remedy the situation. I can find a new case for around $400 and then work through the rebuild which might total out near $700 if everything goes OK. Or, I could try and sell it as a parts bike and move to another bike that's a little newer.

I love the bike but must admit I have been thinking about moving to an '06 or '07 based on thread comments concerning rideability and availability of parts.

What do you think?

  • jayh300

Posted October 13, 2010 - 01:05 PM


that would be a hard decision...
If i had my wr blow up, i would probably fix it.. I have it set up for me, suspension done, protapers, hand guards, skid plates... just the way i like it..
so it would be starting all over with a different bike, to get to where i was on my old one.. probably costing more than the 700 to fix...
but also, if i was going to do cases on an 03, i would want to go ahead and freshen the motor while i was in there, so it would be more than that..
for what i am seeing bikes go for here lately (cheap) don't know how much i would put in an older bike either....
you have a hard choice there...

  • WideRatio

Posted October 13, 2010 - 07:18 PM


You must have had fuel in the crankcase? Never heard of that before. Scary.

If you don't have a bunch of aftermarket stuff, Sell or Part the 03. This is a sign from God. Get the 07 or newer. Its way cooler. A very sweet machine. Your karma is paying you back.

If you do have aftermarket stuff, some of it will prolly fit the 07 and newer. I think its a no brainer. Ride, not fix!

  • schattat

Posted October 14, 2010 - 01:29 AM


It wouldn't happen to look something like this, would it?
Posted Image

  • tribalbc

Posted October 14, 2010 - 05:29 AM


Like jhendr3702 says its all about how much you have in your bike now and how much the bike means to you. If you have the suspension and ergonomics all set for you that can be a fair chunk of change to add to a new bike. If she's pretty much stock then with the price of bikes these days I would probably move on.
I had a similar dilema this fall deciding whether to fully rebuild my motor, (still works fine, just lots of race hours) or get a new 09 YZ450. The new YZ was $6000, I could have gotten $4000 for my bike. It will probably cost me $1500 in parts for my rebuild. But I figured I had spent so much time and money setting up my bikes suspension and ergo's, not to mention battle protection, that it was better in the long run to have the new motor in the WR that's already set up for me.
Besides it's fun rebuilding bikes :smirk:

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  • shoremethod

Posted October 14, 2010 - 06:29 AM


It looks exactly like your picture.
Thanks for the input, I think I'll start looking for another bike.

  • WideRatio

Posted October 14, 2010 - 06:39 AM


So, you go to start the motor and it explodes. Kinda sounds like a James Bond movie, or an incident in Afghanistan.

Not sure if you guys agree or not, but this seems like a big problem. :smirk:

How do you avoid that from happening? Anyone know the cause?

  • - Jake -

Posted October 14, 2010 - 06:58 AM


How do you avoid that from happening? Anyone know the cause?

A backfire at start-up can make the engine run backwards for a moment. The electric starter mechanism on the 2003 WR450F cannot run backwards without causing damage.
If you have a '03 you can fit some parts from a newer year WR to eliminate this problem. If you have a newer than 03 you don't need to worry about it.

  • schattat

Posted October 14, 2010 - 07:30 AM


It looks exactly like your picture.
Thanks for the input, I think I'll start looking for another bike.

Why, it can be fixed!
Like so:
Posted Image

My bike's been running with this fix for over 5000km now! :smirk:

Here's how I did it:
Posted Image

Posted Image

Posted Image

  • shoremethod

Posted October 14, 2010 - 09:24 AM


Impressive work. I don't have the parts that blew out though. I didn't realize what had happened until I got home. Additionally, I have several gears to replace that were damaged as well, which makes me wonder about reliablilty. Our rides usally take us 100s of miles into the middle of nowhere and when things break out there is makes for a very long trip back.
I really like your repair though.


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