76 Cyclone drive sprockets cracked

[sledstorm]

So while I was rebuilding my rear suspension on the 76 cyclone 340 I noticed that the white drive sprockets are cracked. One is clean through on side while the other one is getting started. The through bolts into the round shaft are a little lose but not bad.
Question is what is the recommended path to fix this? Are replacement drive sprockets available? Is there an upgrade to a Liquifire shaft that could be pursued?
Please respond with your recommended direction on this one.
Thank you,
Sledstorm

[jep_800]

I have been told that the white Gates replacement sprockets are no good. You need to find a drive shaft that has the original "black" drive wheels. These are the only one's that are strong enough to last. I needed the same deal, as my 800 has the Gates drive wheels. I found a drive shaft with black ones on ebay about a year ago, so they do show up from time to time. Have to make sure it came off a sled that has the correct shaft, though. I assume the 76' Cyclones are round like the JDX and 800.

Jep

[harleysportster]

Instead of using old drive sprokets from another snowmobile, find a hex shaped driveshaft from a Trailfire and pm Joe Rainville for nos hex drive sprokets, 2.52 pitch.

[sledstorm]

Thanks Jep! The Cyclone does have a round 1 1/8 inch shaft. I would be happy to get new or nos drive wheels, black of course. I was hoping someone might know what to get.

[sledstorm]

Will a trailfire shaft use the same gears? Anything else have to change?
Thx
Sledstorm

[harleysportster]

Finding nos round shaft drivers is harder than finding hex drivers. Use your original gears on the Trailfire shaft.

[sledstorm]

Thanks for all the responses. I am looking for a 79-80 Trailfire hex shaft now. If you have one available please let me know.
Sledstorm

[sledstorm]

I have the parts I need coming. Thanks for all the responses.

[sledstorm]

So I've been through two used shafts and found both had spun the outer bearing. I bought a nos hex shaft and I have new 8 lug drive sprockets. My question is the shaft is 1.25 and the sprocket holes are 1.08 Bothe hex. That seems like a lot of material to press on. Anyone done this?

[sledstorm]

My mistake. The shaft is 1 1/8, not 1 1/4. These will be tight but should press on.

[harleysportster]

The 2.52 hex drivers will press on the Trailfire hex driveshaft. Here is a picture of my '78 cyclone. You do not need the center idler driver that was used on the round shaft.

[sledstorm]

Sweet. Thanks for the pic. Did you bolt them on also?

[jep_800]

That is awesome to know it's an option, but I have a question Pat.... Did the splines on the drive shaft change from 75' to 76' sleds? The correct round shaft drivers I got for my 800 were on a shaft that looked correct, and I thought I would just replace the whole thing with the shaft I bought, but realized that the bottom sprocket wasn't going to fit due to the increased number of splines. So perhaps this isn't an option if you are trying to swap shafts into a 75' 800 or JDX8?

First pic is the original 1 1/8" round shaft and new drivers, and second is the shaft I got them from. Clearly two different spline patterns.

Jason

[JoeRainville]

Jason,

I am quite sure a drive shaft from a 76-84 front motor sled will not fit the 72-77 mid-mount sleds. As you noticed, the spline is different, and I think the length may not be the same either.

Pat,

Thanks for the plug. Unfortunately I am finally running low on 2.52" pitch hex drivers unless I find another stash somewhere. That said, I like to run one in the center position to spread out the drive load on the track even though it's not necessary.

-Joe

[farleyjd400]

For the mid-mounts get the drive sprockets that the Scorpion guys are making. They are the PPD black drivers 2.52 pitch. The center bore is only 1" but and local tool and die shop can make it a 1 1/8" bore very easily and inexpensive. These would also work on the front mount sleds with the round shaft.