G2 driven clutch factory spring setting vs stiff spring.

[Trent3]

Primary is Sabre from CPP. Secondary is a much stiffer spring than factory that I ran a cross. After 30 min of normal use, the sheaves are coated with rubber deposits from the new belt. HP is 22, Secondary sheaves have almost no wear.

Here is what I believe, with the stiff driven spring, my belt is tighter than it needs to be, causing unnecessary belt wear and excess belt tension.

I think I have more torque than I need and would like to see the clutches reach highest ratio at a lower engine RPM.

The factory setup allows for a number of ways the spring can be used with all the holes.

I think winding the spring a bit places more or less pressure on the ramp shoes (depending on which holes are used) If this is true, can it not achieve the same results as using a stiffer spring?

Anyway, last night, the stiff spring came out, the factory spring lays on the work bench with question marks all over it, and I woke up early thinking about it all.

Trent

[sho305]

You are correct. You can get the Umax spring it is stiffer but still factory yamaha and uses the preload. I think Smallblock450 posted the part number here.

The preload (how far you wind the spring to the ramps upon install) controls backshifting. So when you let off the gas it will shift to higher gear and run low rpm....when you have stock or lower preload. The higher preload you use (wind it harder) the less it does that. If you wind it two ramps really tight it will stay at wot rpm all the time no matter your throttle position. It will cool better at more rpm, make more noise and take more gas, and be more responsive. WOT rpm will not change much at all no matter where it is set. I did stretch my stock spring some but it is still in there. I found if you take a gps and have no governor, do a short speed run and record top speed (28gps on my G9 on dirt, more on pavement) then tighten the tension cable under gen pulley until it cuts that down, then let it back out a little. So you have it tight as you can and still get top speed (actually top gearing). That will give you the most power out of the hole and for towing/climbing. The real way to address bogging at low speed is the spring in the primary, the reason they sell these secondary springs that are not really designed to work in there is because stock yamaha primary has no spring in it that would do that job of raising engagement.

Now I have a clone in there, but I also run a HD kevlar belt from CPP that is about 1 1/4 wide it helps it have better low gearing. On top of that I just bought a new secondary sheave that is cut. I put one of those on another G9 it really helped it at low speed and take off. The wider belt also helps more on worn clutches it sort of replaces the lost material in width. Worn sheaves (usually the aluminum ones) will never shift like they should the angle affects shifting. The clone has much more power but this stuff does help it take off better no doubt, my stock belt is not as nice I swapped them back to back. Not put the cut sheave on yet but the other cart has that and new primary sheave it works great. I think half the problems people have are worn belts and sheaves, though tweaks certainly can help the cvt work better for our uses. I have to put the cut sheave on mine yet and plan to get a new primary mine is very worn. The reason the lower gearing works (cut sheave and/or wider belt) is because it gets the engine to shift rpm (rpm at WOT once moving, or peak power it should be) much quicker. The other cart is at shift rpm (~4k) in maybe less than 2 seconds on the level with two people on the cart when you hammer it from a dead stop. It did that with the stock engine before I swapped them, its even better with the clone.

The clone is kind of dead under 2K, so I have a little more preload on it than stock G9 has. But I don't really like it and plan to set it back down once I get the new clutch that will have a spring in it. I hope to be able to pull the front tires off the ground then, I can a few inches now and the primary is not very good. I rather have it idle down at steady 10mph say, so it is quiet and takes less fuel. I also use this cart around other houses/etc. You can get away with a lot with a golf cart, but it starts sounding like an atv they don't like and you wont lol.