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Join Date: Nov 2007
Location: Chandler, Arizona
"The cam/chain design is the achilles heel of the 750." You can say that again. The Vulcan 750 should have been designed like every other Japanese v-twin, with ONE cam chain per cylinder, and a proper cam chain tensioner. I can see no reason for the double chain design, it just makes the engine a lot more complex, and a lot more prone to failure.
Probably what happened in this case is the tensioner failed, but you continued to ride it, stretching the cam chain, which whipped around and destroyed the gear. I would be surprised if it didn't do some other damage, like to the guides and slippers. The fact that it happened to an '05 with such low mileage sounds a bit odd, but I have long suspected the quality of the tensioners deteriorated over the long production run. They were a bad design to begin with, and required very exacting tolerances to work properly. As the manufacturing tooling wore, the tolerances got sloppy, and the tensioners failed right away. I have some experience to back this up. I put 80,000+ miles on my '93 with no cam chain tensioner problems. On my '02, the tensioners failed at around 20,000 miles, and I replaced them with a new set of oem tensioners. They failed at a hair over 10,000 miles. At around 30,000 miles, I switched to TOC manual tensioners. I now have over 70,000 miles on it, and it's still fine. I have not had to adjust the tensioners once, after adjusting them a second time about 2 weeks after installing them. Apparently I did not get them tight enough the first time.
I am a motorcyclist, NOT a biker.
1997 Vulcan 750, purchased about a week ago
2006 Sportster 1200 Low
2013 Royal Enfield Bullet 500, converted to carb
2001 Yamaha XT225, heavily modified
2004 Honda Rebel 250
1979 Vespa P200E
2002 Vulcan 750 parts bike
1994 Yamaha XT225 parts bike