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Discussion Starter #1
Hello fellow Viking owners. Since the clutching market is beginning to draw in some vendors, I think it's a good to time to discuss what's brewing here in my shop. I am working on two clutch systems... one will be for general trail use, the other will be for large tires and/or those that need a very low crawl ratio... possibly lower than anyone has yet to go on the Yamaha Ultramatic CVT clutching system. Some of the parts for prototyping are already here... I'll update as things progress, feel free to ask questions.
 

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Discussion Starter #4
IME, many folks can run a size larger w/o issue... some even larger. For best performance, one really needs to start tweaking the clutch settings as soon as diameter and/or weight of the wheel/tire combo go up.
 

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Discussion Starter #5
For those interested, I have been working with and modifying snowmobile, atv, and utv CVT clutches since 2005. My involvement in modifying vehicles of various sorts dates back to the 1980's, and well before that with other things. My largest clutch project to date was a full development run on the new at the time 2005 Suzuki King Quad 700. The King uses a CVT system that is essentially identical in operation and build to the Ultramatic used by Yamaha. I learned the hard way about ramps angles, lengths, belt tension, and cooling - by doing it myself... through failure and eventually on to the success of an awesomely wide ratio spread. I'm an out of the box guy, and I think you will see this in what I will have to offer you. Now back to shop to continue developing the best clutch parts and systems for the Viking.
 

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Discussion Starter #6
I'm working on a sheave that will provide a low end gear ratio of roughly 3.45:1. This is about 10% lower than any previous primary sheave available. We will have to deal with belt clearance issues, and given that we can surmount that obstacle, things look good. Top end will not be ignored here, but that will be dealt with after we get the low end worked out.

A lower ratio works great for many things. Towing and climbing power, larger tires, being able to drive slowly and pick one's way through obstacles... and if tuned correctly, better acceleration. :cool:
 

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This is something im very interested in once you get all figured out. I really like crawling and working my way through obstacles and climbing hills.
 

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Just curious, what would it probably cost to install something like this?


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The install is pretty straight forward. the clutches come apart rather easy really. and we can get to them very easy on the Viking to. Its something even people that don't have much experience could do.
 

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Discussion Starter #11
Some belts arrived, so I was able to experiment a bit more with ratios. We can likely go lower than the calculated 3.45 ratio. For those of you that like to crawl and pick your way through obstacles, this will be very, very nice. Of course, we are after a wide ratio here, and can tune it. It will also save wear and tear on the wet clutch.

Speaking of the wet clutch, this fairly expensive part can develop excessive wear under certain conditions. Aggressive, hot, low speed riding, large tires, etc. Clutching helps reduce the load on this part. Ideally, and IMO, a oil jet to cool the shoes and drum would be a nice addition, but difficult for most to install. I'll write about that another time.
 
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