HEADS UP!!!

Site upgrade in progress... Core site functions are working, but some non-critical features/functions will be temporarily unavailable while we work to restore them over the next couple of weeks.

Please post any bugs you encounter, but before you do, check to see if it's already listed.

Thanks for your patience while we work to improve the community.

Sign in to follow this  
Followers 0
cardoc

Trusty WR450 died and left me stranded!

20 posts in this topic

I was riding rough gnarly trails all day. I popped over another fallen log and my '07 WR450 (all stock except the GYTR unplug and jetting kit) did a cough and die. I hit the button and the engine just spun over real easy and fast. After several attempts, I swung out the kick starter and gave a couple of stabs. Uh oh, way too easy. Plenty of spark and fuel, but seems like no compression. Get out the rope get dragged 25 miles back to the truck by a KTM and listen to jokes the whole way home.

What happened to my WR? It was running perfect up until that point.

Thanks.

Edited by cardoc

Share this post


Link to post
Share on other sites

I might be wrong but maybe the auto decompression is stuck open not allowing enough compression to build?

Share this post


Link to post
Share on other sites

valve problem? That would explain no compression building etc... but on an 07, that would be really harsh man

Share this post


Link to post
Share on other sites

check the carb vent hoses. the second day i owned mine it did the same thing and it ended up having some wet sand in one of the vent hoses. Took it home cleaned the bike and end of the hose and fired right up.

Share this post


Link to post
Share on other sites

Man, I hate hearing stuff like this. My only consolation is that my 08 has never had a valve even move with over 3000miles. Let us know what you find...

Share this post


Link to post
Share on other sites

wow that is crazy,that does sound like a valve,did you pull plug and look at?maybee something happened to piston.

Share this post


Link to post
Share on other sites

Sounds like you should pull the valve cover and check the timing Chain and valves. pull the plug first and see if you can see anything on the piston and make sure it moves.

let us know what you find

Share this post


Link to post
Share on other sites
Check your hot start lever and plunger to make sure it's not stuck.

Surely that would make it harder to kick, not easier.. The more air you introduce during startup, the harder the bike is to kick.. Try kicking it at WOT and you'll see what I mean..

Share this post


Link to post
Share on other sites

Neither hot start nor throttle position have any effect on how hard or easy it is to kick over the motor.

Cardoc, any updates on the initial problem? Hqve you looked at it yet?

Share this post


Link to post
Share on other sites
The more air you introduce during startup, the harder the bike is to kick..
not true

Share this post


Link to post
Share on other sites

Thanks for the info and ideas. I have ridden Yamaha four strokes for years and they have proven to be rock solid reliable. That's why this was weird. I finally took it apart and here is what happened. First of all - IT WASN'T THE BIKES FAULT! Several months ago I was riding in Baja and by fluke, a branch got jammed between my shock body and the frame. It damaged the plastic air boot/air box. I have since, cleaned it all up and have been riding it with no issues. Well, it turns out, a small broken piece of plastic from the broken air box, after all this time, found it's way through the carb and down into the seat of one of the intake valves and held the valve open - no compression. Removed the small piece of plastic, new head gasket, checked everything else, put it all together and good as new! My fault or a fluke branch - whatever you want to call it. Thanks again for the input.

Share this post


Link to post
Share on other sites

wow...would have never thought of that happening... glad it was a plastic part...

Share this post


Link to post
Share on other sites

Wow, very interesting.

I had just bought a new 09 WR450F because I had heard how reliable they were and just after that, yours was one of the first posts I saw on thumpertalk! I thought ... AHHHH :smirk:

Amazing to hear you could get it going again with no real damage.

Whew.

Share this post


Link to post
Share on other sites

So what did you find dude? We're dying to know what makes a bike just stop running and then not seem to have any compression.

Share this post


Link to post
Share on other sites
So what did you find dude? We're dying to know what makes a bike just stop running and then not seem to have any compression.

did you read post 14 ???

Share this post


Link to post
Share on other sites

Create an account or sign in to comment

You need to be a member in order to leave a comment

Create an account

Sign up for a new account in our community. It's easy!


Register a new account

Sign in

Already have an account? Sign in here.


Sign In Now
Sign in to follow this  
Followers 0