Race reports and previews from F600 events around the country
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- Joined: Sun Mar 01, 2009 9:49 pm
- Location: United States, Virginia, Powhatan
Two F600s were entered: Hank Bilek and Bill Bradley. The weather was cold and misty for the first two groups. The F6s were in the third run group. It was still cold but sunny. Bill's car had no real problems other than an original plug started to break up after 13,000 rpm. Hank's car was very fast until the end of the session when he had jackshaft failure. The F6's were run group two for Sunday's race. Hank fixed his car and both he and Bill took the green flag. The weather was very cold and misty and both drivers spun early and broke their starters and were unable to finish the race. The cars had run there before but since this was the Prodfest weekend many had not seen an F6 before. Everyone loved the sound of those " F1 " cars.
Ken Van Horn Novakar J9
The starter issue is that when you spin "both feet in" is critical as the MC starter is always spinning with the motor and was never designed to roll backwards. If it does then the inside explodes and no starter to get you going again in the race. We have allowed for upgraded starters in the new F600 ruleset that will disengage after starting.
Jim Murphy wrote:The starter issue is that when you spin "both feet in" is critical as the MC starter is always spinning with the motor and was never designed to roll backwards. If it does then the inside explodes and no starter to get you going again in the race. We have allowed for upgraded starters in the new F600 ruleset that will disengage after starting.
Jim, the starter is on a sprag clutch, so it doesn't turn after you let go of the button. When the starter motor is turned, the sprag locks and turns the engine. Once the power is off the starter motor, that sprag is spinning in a direction that is not engaged and the starter is stopped. If the engine turns backwards, it will engage that sprag and spin the starter by itself.
The starter only has plain bearings and is only meant to spin the motor at a few hundred RPM. I believe that the bearings can't handle that sudden very high RPM and most likely weld the starter shaft to the bearing and that's what causes the starter to explode. It's a DC motor, if you reverse the polarity, it would spin backwards just fine.
I've mentioned this several times, the Yamaha R6 starter has ball bearings, and one of the Micro Sprint guys makes and adapter to mount that in a ZX6 I believe. I don't think you can spin a R6 starter backwards at 14k rpm either, but the fact it has ball bearings might give you an extra margin to get on the pedals...
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