I posted this the other day to a minibike forum that I frequent, and I thought it might fit here on my new blog:
Well I finally, FINALLY got to the bottom of the horrific “grinding/binding” sensation at mid-speed / mid-throttle on both mine and the wife’s 6.5hp Tecumseh modded Doodlebug minibikes. Two years we spent with those things literally shaking our teeth out! We didn’t even really ride the bikes last summer because it always felt like we might end up having to carry them home in two pieces; the only way we could motor around on them was by either crawling at low speed or floored-to-the-board (which is not much fun with huge 6.5 horsepower engines!) Yes, I made the auto chain tensioners… very nice… and I changed the drive chains too. And no, still not fixed. Still crunching violently along. Changed the rear axle bearings too. Nope. Double and triple checked engine-to-sprocket alignment… no again, dammit.
Finally, you know, a light bulb went on. I remembered that when I put the bikes together, I had searched for the absolute best centrifugal clutches that money could buy, and I’d ordered up two Hilliard “Extreme Duty” beauties after seeing all the happy feedback (not here, on Amazon I think) regarding them. Well, to make a long story slightly less long, I stared at those bikes long and hard one afternoon after many, many months of frustration, and I decided to roll the dice and replace the still-new Hilliards and their fancy spring setups with a couple of good old fashioned Max-Torques. Swapped them out early last Saturday morning, and hell yeah, we had such a great day tooling around the 10,000 acres of deserted trails that surround our property. We even brought some nippers and a roast beef grinder!!!
PROBLEM SOLVED. MINIBIKES RULE.