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Sooooo. Had a great time on the beach Monday. Decided to take a break and as i shut the engine off i thought i heard a chain noise(still had my helmet on). Wouldnt turn over after that. Sounded like an engine turning over without the spark plug in. Never made it home :(

I currently have a 686 kit and stage 1 cam. Was unaware of decomp mechanisms weakness. Had it break lose when i first did the upgrades. Broke right through my top case of course. Decided to weld the pins and be done with it. Super. everything has been good for about 15 hrs on the motor. Then the beach incident.

Took apart tonight to find the chain broken apart and the half the cam weights down below. The fuckin pin was sheared right off flush with the gear. Not sure what failed, is it possible the chain jumped and broke off that pin? I never replaced the chain guides....wtf....are there any other weaknesses in that area, the 2 bolts were still there that hold on the flanges. the chain was brand new oem. Are the aftermarkets stronger, is there something i left out with the stage 1 upgrade? Can i drill out the top end myself to do manual decomp mod or does it take precision work?

chris
 

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Ouch, I am going thru a similar problem my self. It really sucks. Good luck on fix in it. I am sure we both will be back riding before long.
 

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I'm so lucky to have never experienced this........
 

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Sooooo. Had a great time on the beach Monday. Decided to take a break and as i shut the engine off i thought i heard a chain noise(still had my helmet on). Wouldnt turn over after that. Sounded like an engine turning over without the spark plug in. Never made it home :(

I currently have a 686 kit and stage 1 cam. Was unaware of decomp mechanisms weakness. Had it break lose when i first did the upgrades. Broke right through my top case of course. Decided to weld the pins and be done with it. Super. everything has been good for about 15 hrs on the motor. Then the beach incident.

Took apart tonight to find the chain broken apart and the half the cam weights down below. The fuckin pin was sheared right off flush with the gear. Not sure what failed, is it possible the chain jumped and broke off that pin? I never replaced the chain guides....wtf....are there any other weaknesses in that area, the 2 bolts were still there that hold on the flanges. the chain was brand new oem. Are the aftermarkets stronger, is there something i left out with the stage 1 upgrade? Can i drill out the top end myself to do manual decomp mod or does it take precision work?

chris
Purchase a set of these and you'll never have another failure and you will still have the decompression which I recommend for easy starting and long battery life. I've ran them in my bike for over 60 hours now. Good luck

http://www.wellerracing.com/The-Ori...r-Yamaha-Rhino-Grizzly-Raptor-660_p_2129.html
 

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Did you end up finding the starter motor in your shorts? :D
My son was running the Raptor when this happened in an oval race, we were leading with less then one lap to finish the race, the engine blew in the back stretch about a half lap from the finish line. I still remember it like it was today, my son had about a 50 foot lead on second and then I saw a huge cloud of smoke come off the bike and my son looked under the seat, but never let of the throttle, he practically coasted to the finish line, we ended up in second by mere inches.
The engine sustained a lot of damage, from what you can see in the picture, and the flywheel key being sheared, the Carrillo rod was so seriously smashed and bent, that it had started to seize to the crank pin, and the rod also had shortened about .035'' inches because of being bent............:D
 

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My son was running the Raptor when this happened in an oval race, we were leading with less then one lap to finish the race, the engine blew in the back stretch about a half lap from the finish line. I still remember it like it was today, my son had about a 50 foot lead on second and then I saw a huge cloud of smoke come off the bike and my son looked under the seat, but never let of the throttle, he practically coasted to the finish line, we ended up in second by mere inches.
The engine sustained a lot of damage, from what you can see in the picture, and the flywheel key being sheared, the Carrillo rod was so seriously smashed and bent, that it had started to seize to the crank pin, and the rod also had shortened about .035'' inches because of being bent............:D
If I remember right Ive seen a video of said race?.....
 

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Yes you may have, it is under my profile in some of the videos, the Raptor was yellow at the time.............:D
I knew I had seen it......all I remember is seein the raptor start smokin and it looked like one of those stunt planes with the trail of smoke lol
 
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