kingquad cvt,shim mod and rollers 450/500/700/750 

COOP’S MOD for King Quads. Shim mod details and clutch explanation ‎By Mike Stuart‎ to Suzuki King Quad 450/500/700/750 Topics · What’s a machined clutch mod (Coop 3+) ? The King Quad CVT as supplied is geared unusually tall at the CVT’s lowest reduction, making the wet clutch do a lot of work to bring the ATV from a full stop to the point the CVT gearing starts to take over. (it's like starting a manual out in second gear) This may have been part of early model run changes to make the quad more difficult to wheelie due to liability concerns, but nobody is talking. (an old rumor has it that the first issue of their new 700 CC utility ATVs provided by Suzuki as test examples, were very easy to wheelie and that a dealer, being an unsophisticated rider, injured himself popping wheelies with the throttle. The story goes that the ATV’s were bundled back onto the truck and whisked away and when the production models were later released they were curiously hard to wheelie and have been ever since) In any case the starting ratio of the King Quads is tall and a great deal of low speed work is accommodated by centrifugal (wet) clutch slip, transfering less torque and less easy control than you’d expect. This tall gearing can be improved upon by shimming the front clutch collar by up to 2 MM using the shims mentioned below, and by the machine mod sometimes called the Coop 3+ mod. Shimming is just like putting a lower geared rear diff in a truck, it lowers the overall output range by a bit under 10%. This also means that top speed is reduced by the same percentage. The machine mod lowers the starting ratio by up to 30% without reducing the top end gearing at all. The shim mod (which should be called the Coop mod after it’s inventor Arnie Cooper), with the mentioned compromise, is the easiest (and cheapest) mod to do at home. The machine mod requires you send your outer front sheave to be modified and return shipped. 1) If you have mounted 26” tires then the Coop mod will pretty much return the overall effective gearing to what it was with 25” tires. If you have bigger tires than that the mod will improve response in like proportion. The gold standard of course is the machine mod.  2) Once a machine modded sheave has been installed and run for 10 minutes or so to buff the surface to the usual grey, it would be difficult for someone to tell that it has been modified at all without his using good measuring instruments and a stock new sheave as a control example. There is no center ridge and the transition point looks like normal wear.  ps. Once bigger tires have been mounted on any King Quad, the King’s speedometer cannot be used as an accurate gauge of speed. It drives off the motor’s final drive so it will not measure true ground speed but rather something less. The King Quad’s speedometer cannot be calibrated to tire size. True comparisons can be made using a GPS to measure speed. A machined mod tapers the clutch face from stock to 2.25 - 2.65 MM further in at the center. This retains stock gearing at top speed while reducing the low end to 25-30 % lower than stock. Belt wear has not been an issue yet to anyone's experience. A Carlisle UA437 lasted over 12,000 kilometers. Used with a 1 MM shim (for use with bigger than 25” tires), the low gearing will be as low as the clutch system allows. You can get the shim from a Yamaha dealer, part number 90201-225A4-00 WASHER, PLATE (Thickness=1.0) - If a clutch kit has been or will be installed it is better if the sometimes included EPI ‘wet springs’ (stronger centrifugal clutch springs) are not installed. Such springs are a ‘poor mans’ way of getting more snap in the low end, at the expedient of making the centrifugal clutch slip until a higher RPM. With the machining mod the wet springs aren’t really necessary and technical fine control may be a bit more finicky as the motor will be operating at a higher RPM at the engagement range. For dedicated mudders though, the wet clutch springs allow a harder launch out of the hole. As long as the compromise is acceptable. A stronger secondary spring is a good idea as the belt contact patch at full reduction is smaller than it was. Mods such as lighter rollers or sliders or stronger secondary springs (the retail 'clutch kit') can delay the upshift of the CVT, allowing stronger drive when the quad is going fast enough that the CVT is within its operating range but they don’t have any effect until the ATV is going fast enough to have started to upshift. They do nothing to change the starting ratio. You are still starting out in second gear. The stronger wet clutch springs offered as part of some clutch kits are an inelegant way of getting more starting out performance, they extend the range of wet clutch slip even more than stock. The only way to get a lower starting ratio would be to put really small diameter tires on the quad (as if), or to do the shim mod, which does help the situation some, but will reduce your top speed too, or... do a Coop 3+ style CVT mod that will reduce the starting ratio 25-30% and will not reduce the stock top speed in either range, at all. The upshift delaying mods (clutch kit) do work well in conjunction with a Coop 3+ machined mod, enhancing available power in the mid range as they are designed to do. They just don’t help where the help is most needed.  The mod is much more than just chucking up the sheave and machining it, the sheave has a grease seal located flush with the front sheave's inner belt running surface, and to do a proper job that will allow lowest reduction to be achieved this seal pocket and seal must be relocated further in to remain flush with the running surface, a step that has its own challenges. 　 The result of a machined mod to the outer front plate is a CVT with an increased operating range that permits much better fine control for technical situations, and improved tractability when one has to slow down in high range to negotiate an obstacle before resuming speed. And easy wheelies. 📷

Good stuff....lets see how she does when its all done.

What about Sheave machining? I here there are many people who can machine your sheave and although more costly then shims, you can keep your top speed? Any experience doing this?

Hey man, is there A link to your video drilling these roller weights?

How much did it help just doing the 1.5 shim on your 500 I have a 20 kq500 also wondering how much it helped in pulling

What brand is this Kingquad? Suzuki?

Any idea what's the torque for the main clutch bolt?

What kind of snorkel do you recommend

What do the shims do? And drilling the rollers? I have a 06 700