Gear Tooth Broke, Locked Up My Bike on Freeway - 99 WR400

[ch4rlie]

I decided to go on a ride up to the public lands in Santa Barbara, a couple of my friends were driving my truck and I was riding my wr400. Was going about 75mph on the PCH when out of nowhere my rear tire completely locked up and I skidded off of the freeway. It all happened really fast but I managed to stay on the bike by trying to counter the steering pull from having your rear tire freaking locked up solid.

Took one look down at the bike on the side of the road and new I was F'ed. The chain was completely slacked because the output shaft had moved back about 1/2 and ripped partially out of the case. I decided to take the entire thing apart, and low and behold in the bottom of the case is a gear tooth!! Wow, must have broken off and caused the gears to get stuck. I had just supermotod my bike out with warp9 17inch wheels. Everything else on the bike was done pretty bad, the blinkers didnt work, license plates lights were crap ect. So I ordered an older baja designs kit off of ebay (some universal kit) new plastics, trail tech speedo, graphics, everything and proceeded to slowly start rebuilding my entire bike. At one point I had every piece of the bike laid out on the table.

Now here is the worst part of the entire story... My friends wanted to go on a ride in mullholland and i had finally finished redoing everything on my bike. Right before I went on the first big with all the rebuilt stuff, i wanted to make sure there was no metal particles at all in my motor, so even though i had just put new oil in, I drained all the oil and put in a new oil filter... then.... wait for it!!!!! never put any %&$#ing oil in before the ride.

Crazily enough I rode in the canyons for over 45 minutes!!! (i even drained the frame oil) until I came to a stop sign and the bike died. There was no compression at all and I had to walk to the bike a couple miles to get to a place where it was safe to park. Well when I realized what the hell had happened, I could not believe that I didnt sieze my motor or something like that. I was so pissed off that I brought it right back to my house and ripped off everything and inspected the cylinder and piston, only to find that it was still in perfect condition.

Pushing down on all the valves from the top, I realized that the right intake valve didnt open up even when you pushed on it. So I guess the valve must have gotton stuck and the piston hit it. Look how bent it is in the photo. Oddly enough I cannot find any damage whatsoever to the piston! Anyone ever hit a stuck valve and had the piston be perfectly fine?

Edited August 1, 2012 by ch4rlie

[Mtn-Track]

If I understand your summary right, sounds like the dry engine seized a valve, then the piston slammed the valve which is probably what chunked the gear, followed by the full lock-up when the gear missed a step and blew out the case. Sucks nonetheless!

Good thing it didn't superman you on the freeway!

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Edited August 1, 2012 by Mtn-Track

[GlennR]

You should limit your beer intake during the next rebuild.

Actually, it's better that you screwed it up yourself than having paid some crappy mechanic to ruin your bike.

As the saying goes, "I bet you'll never make that mistake again."

Good luck getting her on the road again. ?

[AKmud]

If I understand your summary right, sounds like the dry engine seized a valve, then the piston slammed the valve which is probably what chunked the gear, followed by the full lock-up when the gear missed a step and blew out the case. Sucks nonetheless!

Good thing it didn't superman you on the freeway!

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Actually sounds like two different incidents.... The no oil story was after he rebuilt it from the chunking gear story.

[ch4rlie]

Actually sounds like two different incidents.... The no oil story was after he rebuilt it from the chunking gear story.

yeah the oil story happened after i spent all the time fixing up the bike from the catostrophic gear failure... which was caused by who knows what since i have always been very on top of oil changes. (well except for that one fatal day)