780 series driven issue

[Gusrat]

I have a 780 series drive and driven on a duromax 713cc on a buggy. When I go uphill I lose a ton of power and bog and if the hill is steep enough don’t even make it up. I’m thinking the spring is not stiff enough. Anyone know where to buy a stronger spring? Also my pulley is outbound.

 

[Whitetrashrocker]

Is your belt worn?
Post some pics so we can see what your dealing with.

 

[Kartorbust]

Tire size and sprocket teeth count for each one? Picture of the setup would be great to help.

 

[Master Hack]

Then tire pressure, vehicle weight, actual HP, your address, SS number, employer and credit score, that should get us started.

 

[Gusrat]

Here’s a few pics. Let me know what exactly you’re wanting to see. But my tire size is 25inch 11 to 44 sprockets. And the belt is brand new.

 

[Gusrat]

Sorry I didn’t clarify, the driven spring on my tc is what is think i need to fix. I think it’s switching into lower gear too soon.

 

[Kartorbust]

You need to deepen that gear ratio. Need to be closer to 8:1 to work with that. Your at 4:1, though looks like you might have a gearbox that has a 2:1 internal ratio which would give you about 8:1, if its the gearbox I am thinking of.

 

[Gusrat]

That’s the gear ratio I have

 

[Whitetrashrocker]

Is this a new problem? Has it always been like this?
Maybe the spring broke?
Have you raised the rear tires and watched the CVT go through its motions?
Do both parts move smoothly when rpm rises?

 

[Denny]

There’s no gearbox there. So that means his gear ratio is fubar. Switch to a 60 tooth axle sprocket and a 10 tooth drive sprocket and I’ll bet you love it. A 72 tooth axle sprocket would be even better.

 

[Hellion]

What buggy is that? I'd want to see the other side, the right side of the engine area to see the final drive to the axle....I bet that V-twin sounds nice.

 

[Kartorbust]

There’s no gearbox there. So that means his gear ratio is fubar. Switch to a 60 tooth axle sprocket and a 10 tooth drive sprocket and I’ll bet you love it. A 72 tooth axle sprocket would be even better.

That looks like a reverse gearbox to me hooked up to the driven there.

 

[Gusrat]

There’s a better picture

 

[Gusrat]

What buggy is that? I'd want to see the other side, the right side of the engine area to see the final drive to the axle....I bet that V-twin sounds nice.

It’s a old yamabuggie that I’ve been piecing together.

 

[Whitetrashrocker]

There’s a better picture

Your driven is backwards.
The red should be the leading wedge.
The yellow should have to fight to get down the ramp as it rotates.



You need a reverse wound spring or flip the whole unit around.

 

[Gusrat]

Do you know where I can get one

 

[Gusrat]

Your driven is backwards.
The red should be the leading wedge.
The yellow should have to fight to get down the ramp as it rotates.

View attachment 159068

You need a reverse wound spring or flip the whole unit around.

How can you tell it needs a reverse wound spring? I know very little about these tc’s. When I bought it it said that it came with a outboard spring.

 

[Kartorbust]

Normally the part that has the spring, is on the outside of the jackshaft. Yours is on the inside. A reverse wound spring will allow it to operate properly when its mounted the way that it is now.

 

[Gusrat]

Hm I’ll have to take a look at it when I get home. Gopowersports said that’s how to install it. But I’ve also heard that they also aren’t the best.

 

[Whitetrashrocker]

780 Series | Comet Clutches

You said a 780 series CVT.
Thats the driver part.
Which driven unit do you have?
Looks like a simple diameter measurement will determine it.