99 400 intake valves stuck

Has this happened to anyone? I went riding with my son on Friday. We were just warming up, practicing jumping. When my bike just reved up, then died. Kicked it over without the compression lever, then I was depressed. Short day of riding.

Took my bike home and checked for the cause. Found the middle bearing ride, (bushing?) had galled and caused the aluminum to push down and hold the intake cams open. Checked the oil in my bike, all ok. Checked all of the oil passages, ok.All other areas of the cam were lubricated. I'm currently in the process of putting the engine back together, and still haven't found the root cause. Has anybody else had this happen? Could you tell me what was the culprit? All of this happens when I finally save enough $$$ to have my suspension done.



OOOPs, I meant intake valve, not cam. :)

It could be the bolts were overtightened. Cam cap bolt torque is fairly critical. Either that or it really is getting starved for oil, for one reason or another. You can remove the 8mm head bolt that is on the side of the head right in front of where the external oil lines run to the head. At idle, this should put out a LOT of oil. It only takes a second or two to make a big mess.

My machine conked out suddendly too. Will idle, but at 1/8 throttle it bogs and blows fuel out back of the carb (fired up once briefly w/o airbox). Pulled carb and soaked/blew 6x over last four days. No fix. Pipe get scorching hot (maybe cuz I can only idle) on the several tests after cleaning).

The bike is new (2 weeks) and ran like a top till this. Jetting was spot on stock. I tried richer, etc while fooling with carb. Could get her to smoke, but same bog/blowback problem.

Twice I idled around the yard and she came back to life for only a few seconds then it died suddenly. I waited a second and it fired back up but was back to idle only mode again.

Is it possible that intake valve(s) are stuck part shut, causing blowback.

Been dead for days. Running out of options. Anyone else out there with sudden death syndrom?.

have you checked timing?


Could be a bad CDI or possibly a problem with the TPS. Kinda sounds electrical if it worked intermittent.


[ May 07, 2002: Message edited by: sticky ]

[ May 07, 2002: Message edited by: sticky ]

[ May 07, 2002: Message edited by: sticky ]

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