Big Block driven clutch question

popper

So I installed my big block with new drive clutch. What is available to upgrade driven clutch as far as complete clutches and or upgrade parts.? What changes will affect what? Are there any good articles to read about clutch adjustments?

96 Ezgo with 25 hp Kohler Command

popper
John Lynch

BGW

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BlackBerryHill

There are very few options for the driven clutch. With a 25 hp motor you won't notice the benefits of modifying the driven clutch anyway. These big blocks have so much power that mods for stock motors go unnoticed. You can choose between two factory clutches, the 28 and 36 degree. However, the 28 will not create enough difference to notice with so much power coming from your motor. I'm waiting on a new driven clutch for my cart now because the original came apart inside and could not be repaired. I'm getting another 36 degree factory clutch with no mods. The factory clutches have three positions for the internal spring to be adjusted, but here again you probably won't feel the difference. You could send your factory clutch to CPP and have them machine it for you.

http://www.cartpartsplus.com/perform...utch-machining

The above link should take you directly to their page about machining the driven clutch. I think it is mainly intended for factory powered carts that need a little assistance, but you could call them and ask before sending your clutch. They will also inspect it before machining it to ensure it is worth the money. You can also try searching this site for clutch mods, but you will find little about the driven clutch since there are few performance mods available.

I will keep an eye on this thread to see what you decide and how it works for you. I may learn something new, and I'm always looking for better ways to set-up my cart. Good luck and keep us posted on which way you go.

1989Marathon

What are you looking to get out of the clutch? Why do you feel the need to change it?

popper

1989,
thats a good question. I really didnt know if I needed to or not. Was looking for some info on whether changes would make a difference or not. Maybe the better question would have been that I have installed my big block and if any one had to do any driven clutch work or changes to help performance. It actually seems fairly decent. When I mash the gas from a standing start it will lift the front tires slightly and they will dance for a couple of feet and then set down and rotate, maybe I'm expecting too much.

popper
John Lynch

1989Marathon

Like this?



I've found that the stock Ezgo secondary works great with the big block motor. Is your secondary spring adjustable?

popper

Pretty close to that , but I weigh about 240 so that could be a handicap, lol. How do I know if it's adjustable?
popper

1989Marathon

Yeah, but you got me by 9hp...
Look at the back face of the helix(ramp) and see if it has a small hole in it(3/16"). The spring tang sets in that hole and there are 3 holes on the inner sheave for adjustability. My last Ezgo cart did not have the hole in the helix, just in the sheave. I bought the right spring, and drilled a hole in the helix.

popper

1989,
I'll check it out tomorrow. Thanks for the help
John Lynch

sho305

In a yamaha you can get a cut sheave, they cut the center in some so the sheave will get closer to the other one at rest/low gear. This lower gear is ideal for very slow going steep hills or towing something. Above maybe 5mph it has no effect. I rebuild the primary in a cart with a new sheave and other side is iron with no wear, then did the same with the secondary but put a new cut sheave on it. It works. Then I put a clone in that cart later. It helped the clone a fair amount I thought, because it would get it up to shift rpm much faster, at a slower speed. The clone with two people on it would get to shift rpm (maybe 3800) in like 2 seconds from a dead stop.

What also does this to a point is the HD kevlar belt CPP sells for yamaha because I think it is 1/16" wider than stock. So of course it rides the secondary higher than stock and does not seem to affect top speed.

Anyway not sure if that helps you with a ezgo. I just bought a new cut sheave for my cart as my sheave is worn more than I thought it was, nearly worn through (.014 left). I will report how it changes it.

I also ground the ramps on this sheave long ago with the stock engine, but only about the first third. The lower angle made it rev quicker for better towing. I'd rather have that for a trail cart because I like them to shift out at part throttle, but shift back when you nail the gas...it was much more responsive with the cut ramps/helix. Not sure I want to experiment with the new one though, lol.

The preload on the secondary spring keeps it from shifting out at part throttle. The more preload you wind on it the higher the part throttle rpm, so better cooling, better response, more noise, more gas. WOT is not changed much if at all. If you wind it really hard it just stays at shift rpm all the time you are above 5mph or so. The holes let you put the spring at different rotations to get different settings. It is more how you want the cart to run, as it does not change full throttle operation much at all. I ride around some houses so I like the rpm to drop at part throttle and be quiet.

1989Marathon

Sho, Are you comparing your clone to a big block? It's night/day when setting the secondary. The principles are the same, but a big block is much more forgiving if you are off a little bit. With the added torque, you have alot more room for error.