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hello
i have a mc91 with a dyna drive and cant find a clutch for it. i'm thinking about doing away with the dyna drive and doing a direct drive (no clutch). does anyone know where to get a crank shaft sprocket for a mc91? any help would be great
thanx

Paul, I've seen the yamaha ones on ebay and have heard that the Taper is very close. you could possibly lap them in.

Hi, Paul,

Try Hanson or Randy Duncan at Randy's Engine Service. They've got a pretty decent stock of MAC items.

Listed in the parts and resource section.

Warmest...

I have a direct drive sprockets, 1/8 tooth used . one 9 tooth , six 10 tooth , four 11 tooth and four 12 tooth. if interested call me at (440) 967-7929. Herb Dickel

Paul,
I think the dyna drives originally were for direct drive, can you set it up that way?

Jeff

A McCulloch bolts direct to the side of a Dyna Drive to run to direct drive. Crank goes inside the box and drives the gear.

paul, we had a dyna drive gearbox on a dart grand prix 1965. i actually was able to finish some races. we ran a mac, direct drive. robb is very correct, the 4 mac 'side bolt pattern' lines up perfect. an idea only, my dad measured the length of the bolt to get as much thread as possible, then he drilled the head of the bolt so that he could 'safety wire' all 4 bolts together. of course, after a race date, he would pull the top cover and inspect. one time when wiring, he dropped the wire inside the gearbox. i had a faster lap time getting out of the garage then at the race track...we soon went to the max torque clutch system and wb820(b-limited class then)..had some clutch probs, some thought lack of good airflow(it was my driving)..if you do go clutch route, try and find the large ring(clamp) that holds the clutch mounts together, much quicker to take apart than the 6 bolts..gear ratio, 8.00 to 1 or 7.48 to 1....7.05 to 1 for longer tracks..gearbox oil, we just ran what pro distributor(kart shop) sent us. today, i don't know...had good luck with gearbox, enjoy butch