My new 4 Stroke now has smoke!

Hey Guys,

I'm looking for advice from anyone who's been into a WR450 motor or has and idea of what I might be looking for. I sank my 04' WR450 last weekend and it took on much water. After limping back home, flushing clean oil through it three times, and running it for short periods it's now smoking when you gas it, and is making some detectable noise from the top end. After removing the valve cover and visually inspecting it as best I could, I cannot find any visible damage to the Cams, cam chain or sprokets, or valve tappets. There is still some grey sludge in the valve cover, but lubrication seems good. I don't see any visible evidence of metal in the sludge. Plug is wet with gas upon checking it, but no oil. I figure the smoke is either from oil around the rings or valve guides. This bike only has 450 miles on it so I'm hating to have to go into it, but I want to make sure the motor is ok and fixed right if it has to be torn down. Any idea what might be causing the wining noise from the top end and the smoke when throttled. The bike cranks great, and has plenty of compression. I do plan to compression test it.

Thanks Again.

What color was the smoke? Blue, White, Black?

I did the same thing to mine, it's the valve seals. Mine was smoking badly, even just at idle, enough to smoke out the whole yard. I ended up tearing down my whole motor and replacing a bunch of parts. It sucked up mud through the vent tube coming off the valve cover which vents down by the skidplate (stupid design!!!). Sorry if this upsets you, but it sounds like you've got trouble like I did.

The smoke was white. Doesn't smoke at all during idle. Smoke increases with throttling.

The valve seals are definitely where I was thinking the problem was. What else did you replace. I figure if I have to pull the whole top end I might as well do it right. I totally agree with the bad location of the breather tube. Mine will be moving to the air box soon. Thanks!

I ended up replacing the valve seals, rings, connecting rod and bearing, main bearings and most of the bearings in the cases. They were all full of silty grit and wouldn't have lasted long. The top end parts all seemed pretty good (valves, cams, etc.). The bitch of it all is that now I have a coolant leak problem that I haven't solved yet, I think I need to resurface my head to get a good seal on the cylinder.

After I sank the bike, I rode it maybe 5kms back to the truck, then immediately changed the oil, but by then it was too late, the damage was done.

Good luck with yours, hopefully it is not as bad as mine was.

I easily rode as far back as you did, maybe farther. I think the damage is definitely done. Did you have any detectable top end noise at all? I'm going to pull the top end, try to flush the rest of the motor and hopefully go with that. I don't want to put it back up not knowing for sure that I fixed what was causing the noise. Yamaha's service manual shows pulling the two oil lines on the front of the engine lose to flush the system.

It's amazing how quickly the muddy water gooped up and has set in every part of the engine. Sure wish I'd moved that breather hose sooner. :naughty:

I wasn't getting any strange noises from the engine, but after I repaired everything, the engine 'seems' noisier than it used to, but I'm figuring that this is probably all in my head.

You'll have to let us know how you make out with the teardown, and again, good luck.

Cedric, I know I'm wearing you out with questions, and I do apologize, but I have one more. Did you do all of the head and cylinder work yourself, or do you have some place you can suggest send mine to? The cycle shop I use most of the time sends their machine work off somewhere, and to save a couple of bucks I figure I'd cut out the middle man.

Thanks again for the info!

Thought I'd reply with this piece of info I found so everyone could find this stuff if they ever need it. If I try it I'll definitely let everyone know how it worked out. This is a flushing system for your bike engine.

No worries about the questions, but I didn't actually do any machine work. I did all of the disassembly myself, actually I did everything except for the replacement of the connecting rod, as I don't have a press and the balancing tools required. I had that work done by LRX performance near Calgary.

Even if I had a good shop in mind, I doubt you would want to ship your parts 4000kms to Alberta.

My bike let out quite a bit of white smoke after I cleaned and washed the air filter, but didnt give it time to dry.... it was sucking water into the engine from the wet airfilter, and in about 20 minutes of riding time, it quit smoking, and hasnt smoked since.

Re-route that air hose, it should be run into the airbox from what people on here have told me this problem wont happen again the next time you stuck in water/mud.

I'm in the process of doing that mod now.... now that I'm done winterizing my sled.

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