1st mechanical issue in 4 years?

My WR450 stalled at a traffic light, started again and then on the way home it quit for a second, fired again and kept going and then sputtered again.

Fresh high octane gas in it and fresh oil. Couple of thousand miles on the plug, valves have been adjusted. Never a sputter before.

What might this be?

Thanks, Greg.

Sounds exactly like a bad CDI to me. In the Electrical part in the back of your manual, do the 9 step Ignition System test and if the CDI is bad......it will be determined by method of elimination.

Now here's the kicker......LOL:smirk: .....I have an "as new" Dynatek Ignition in the classifieds that is for 03-06 WR450. Not sure what you have but it would cost the same as an OEM CDI and is much much better. I not trying to push a sale but I had a CDI go bad exactly like your describing.

Could also be water or dirt in the carb, bad electical connection/ground, failing crank position sensor or a failing stator source coil. CDI's rarely fail so I'd look at everything else first.

I agree with William1, you need to check out all the cheap mechanical issues that he mentioned, first. The CDI's, while rare, do fail however and your description sounds just like the first time the old '02 WR 426 had a problem. It got progressively worse, a little at a time until the bike wouldn't run anymore. I had a friend lend me most of his electrical system and one peice at a time it was diagnosed down to the point of getting a new Vortex X10 CDI and the bike ran and still runs great after that. Hopefully it's just some bad fuel or O-ring that's causing the problem. WR Dave

I agree with WRDave and William 1 that you should check other things also but the electrical check is easy to do.

By the way, I've owned both the Vortex X10 on an 06 WR450 and a Dynatek ignition on the same bike and the Dynatek is hands down much better. It is also cheaper to buy yet better in quality, more capable in functionality, and customer support is awesome. Vortex X10 is made in Australia and Dynatek is made in USA. Its just that the Dynatek for WR450's is less than a year old and not as many are out there yet.

The bike has a little too much oil in it, reading full on the dipstick. Any chance that could account for the sputtering?

I have not had a chance to take it out again to see if it gets worse or happens again. We wil see.

The bike has a little too much oil in it, reading full on the dipstick. Any chance that could account for the sputtering?

I have not had a chance to take it out again to see if it gets worse or happens again. We wil see.

I don't know about the oil, but check for a clogged gas cap vent. My 400 vent would freeze now and then, and quit, run, quit, similiar to yours. Check the vent or simply loosen the cap a bit and ride and see if it cures the problem.

I just noticed that you're in BC. If you're riding near the freezing point, your carb vent hoses may be icing up. The group of hoses that hangs down behind the engine can plug with ice and mess up the carb. I shortened my hoses so they end at the back of the engine, keeps them warm.

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