All of a sudden today while riding, I got this Cling-Klang sound coming from my left side of the engine. worse at lower rpm's. It turned out to be the rivets working loose on my flywheel. My local Yamaha shop has not seen this on the thumpers but has seen it with the Yz's. Has anybody else had this happen? My 02 WR250 is 16 months old, I ride a fair amount, mostly in the desert. I'm on my 3'rd set of chain and sprockets, changed the cam chain at the 1 year mark. I've run the YZF cam timing from the begining and now have had an 03 YZF exhaust cam for a couple months. Maybe the guy in charge of riveting the flywheels onto the hubs was having a bad day the day mine was built.
Fly wheel rivets came loose
Started by Butterman, Feb 27 2003 04:22 PM
9 replies to this topic
Posted 27 February 2003 - 04:22 PM
All of a sudden today while riding, I got this Cling-Klang sound coming from my left side of the engine. worse at lower rpm's. It turned out to be the rivets working loose on my flywheel. My local Yamaha shop has not seen this on the thumpers but has seen it with the Yz's. Has anybody else had this happen? My 02 WR250 is 16 months old, I ride a fair amount, mostly in the desert. I'm on my 3'rd set of chain and sprockets, changed the cam chain at the 1 year mark. I've run the YZF cam timing from the begining and now have had an 03 YZF exhaust cam for a couple months. Maybe the guy in charge of riveting the flywheels onto the hubs was having a bad day the day mine was built.
Posted 01 March 2003 - 10:45 PM
I put that flywheel weight on mine. Hopefully, that's not the only thing keeping mine together. LMAO 
That moisture has sure been great for riding.
That moisture has sure been great for riding.
Posted 02 March 2003 - 12:18 PM
I just put up a post then found yours. My son's 2001 YZ250F's flywhell came apart in october on the finish line jump at an arenacross race causing him to break his leg and was warning others to check their flyeheels.
Posted 03 March 2003 - 03:33 AM
All is better now with a new flywheel mounted up, there was a lot of nasty sounding noise coming the bottom end when the rivets came loose. My Scotts filter did an awesome job catching the rivet particles, but I'm still doing several quick flush engine oil changes to make sure everything's cleaned out. My yamaha dealer is going to comunicate with yamaha about the failed rivet problem and I'll post any word I get back from them.
Posted 03 March 2003 - 07:06 AM
You have been lucky.The bike shop my mate bought his WR from has had a few 02 bikes with this problem.This happened to my mates bike and had to have a full rebuild under warranty.
Posted 06 March 2003 - 02:56 AM
This is from Eric Gorr´s site: http://www.ericgorr.com
Shattered Flywheel
Flywheels can occasionally come apart. The reason for this is worn main bearings. The crank is supported by the primary drive gear on the right side of the engine. When the main bearings wear, the crank deflects more on the left side where the electrical components are mounted. When the flywheel is allowed to gyrate, the flywheel rivets will eventually shear.
Shattered Flywheel
Flywheels can occasionally come apart. The reason for this is worn main bearings. The crank is supported by the primary drive gear on the right side of the engine. When the main bearings wear, the crank deflects more on the left side where the electrical components are mounted. When the flywheel is allowed to gyrate, the flywheel rivets will eventually shear.
Posted 06 March 2003 - 03:41 AM
I seriuosly doubt that the main bearings on my 02 are junk, I think we would have heard of crank bearing failures on 01's if that was the case. We stuck an indicator on the crank and the only play that was measurable was end-play, no radial play. I beleive the rivet holes were machined slightly oversize and over time allowed for the rivets to start working loose.
