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Gearing for Avon
#11
Michael, When I was at Avon for the Historic & Minibike Event last month, I experimented with different gear sets, trying out 7.2:1, 7.4, and 7.6. All were driveable, but I preferred the steeper ratio specifically for that last hairpin, with the compromise being that I will feel compelled to take it easy on the long straight, lest I discover the upper limit of my reciprocating assembly's elasticity. With 9-66 sprockets you're at 7.3:1, so I assume based on my experience last month that you will be adequately equipped for your stated objectives.
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#12
Michael, the best thing is to PM Scott Kneisel and see what he recommends. After all, it's his venue and he knows the track well. He runs classic engines like yours and is a great guy to know. Also, I'm with Dave: Just go and have fun! Ted
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#13
Ted, What if over-analyzing gear ratios is part of the fun? Smile
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#14
Maybe it is fun. I'm at the point where I can walk around a track and know what ratio I want. I admit that I hate to have to cut and rivet a chain just to change bottom gears. I HATE to wrench at the track. I'm also used to the West Bend, that has enough torque that I never am forced to run a 9 tooth engine sprocket. I'd rather run a 70 or 71 tooth bottom and keep the 10 tooth clutch. One real reason to run the 10 tooth clutch is that it has a needle bearing. I dislike bushings. I don't even run a 9T at Fremont, and Fremont's fairly tight. Maybe if I ran a Mac, I'd be forced to go with the 9T drum. Undecided  TJ
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#15
One word: Gearbox. Ha, ha. But you know that already. Wink It may not be the epitome of lightweight, go-fast gear, but it is definitely a time and maintenance saver.
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#16
I have to agree with Kurt. While the gearbox may be slower and heavier, there's a lot to be said for a bullet-proof drive system and the ability to change ratios in 4 minutes. So I'm going to go one tooth smaller than I did last year to account for the track changes and sort it out on Thursday. See you there!
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#17
I'm trying a Dyna Drive myself. There aren't many Dyna Drives with a Rev Grip in an oil housing running on West Bend 610's, but we've designed and machined the housing, output shaft and mount plate, and we'll try her out at the big November Tucson event! Yall come on down. We've built several of the same setup for the Mac '91's as well. Ted
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#18
Maybe someone with experience at both tracks could offer me some insight towards gearing correctly for Avon as I have never been on that track. At Nicholson I was running a 9-66 with a truly stock MC-20 in the historic class. I felt I had two issues, one I felt like I was at the peak RPM's a touch early on the straightaway and people easily passed me on it, second I felt a bit sluggish out of the hairpin. I qualified 3rd with a lap time of 28.4 and the fastest qualifier posted a 26.0 that's a 2.4 second advantage they had on me. So that opens up a lot of questions, was I under geared? Did they have more power than me? Were they better drivers??? So any suggestions for gearing for Avon?
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#19
(07-07-2018, 06:41 AM)John Wolkiewicz Wrote: Maybe someone with experience at both tracks could offer me some insight towards gearing correctly for Avon as I have never been on that track.  At Nicholson I was running a 9-66 with a truly stock  MC-20 in the historic class.  I felt I had two issues, one I felt like I was at the peak RPM's a touch early on the straightaway and people easily passed me on it, second I felt a bit sluggish out of the hairpin.  I qualified 3rd with a lap time of 28.4 and the fastest qualifier posted a 26.0 that's a 2.4 second advantage they had on me.  So that opens up a lot of questions, was I under geared? Did they have more power  than me?  Were they better drivers???  So any suggestions for gearing for Avon?
I doubt anyone was running anything stock .. at a minimum they was prolly running alky ..
and geared better ..not to mention you was running against mc7, mc9., mc90 ..  and then big bills totally modified mc45 (101a)..   lol..  you didn't stand a chance ...
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#20
Hi All I run 9 /62 but im light, 150 lbs, but with the new corners added, maybe 9/64 -6 Richie
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