Torque Converter Driven Pulley

[Darian1m]

Hello, go kart noob here. I bought a cool go kart and am trying to make it ride able again. It burns through belts like crazy so I am trying to get down to what the issue is. First I am simply trying to take it apart and give it a good cleaning as there are fragments of kevlar from the belts left over in the pulley.

So here it is, how do I remove the driven pulley? It just spins when I put a wrench to it. See pic below, any help would be appreciated! thanks

 

[itsid]

burning through belts is likely a gearing issue.

A rusted sheave will not exactly help, I agree;

Grant made a great video to provide help cleaning your series 40

watch it closely prior starting tearing your's apart. (multiple times to let sink things in )

http://www.youtube.com/watch?v=a3FCcLlR-sg


still, it might not be the TC at all.
weight wheelsize and teethcount on your sprockets could help us to verify your ratio (it might need to be changed)

'sid

 

[itsid]

still, it might not be the TC at all.
weight wheelsize and teethcount on your sprockets could help us to verify your ratio (it might need to be changed)

'sid

Ahaa.. from your other thread

Two seater
12 HP engine
9 sproket gear behind the driven unit
54 sproket gear at wheel axle
22" wheels

there you go, even a 12hp engine will not push that weight on a 6:1 gear ratio with 22" tall wheels

keep in mind that your kart weighs ~300 lbs alone,
and has a max capacity of 550 lbs (that means you and whoever sits next to you must not exceed 250 lbs combined!!)

then (550 lbs total weight) 6.6:1 ratio is what you're going to need to save the belts from frying up.

So either, get a bigger axle sprocket (60 Teeth)
OR get a set of smaller wheels (20" should do already; 18" would be better of course )

'sid

 

[KartFab]

Ok lets just be clear here about gear ratios.

There are gear ratios for centrifugal clutches, which really really do matter a lot
Then there are the same ratios for larger tire karts that 'conflict' with the advice most commonly given out for centrifugal clutch driven karts.

The 6:1 ratio is golden, unless you have large tires, and then its still OK with the right torque converter and engine.

So the 40 series torque converter with a large engine (not the 5-7hp, but a 9-13 hp engine) can be geared with 22" tires to 40 mph with no problems whatsoever. It will take off the line fast, and accelerate well, climb hills etc...

Just kind of compartmentalize ratios into 3 categories for 'fun karts', w max speed as a guide:

1) centrifugal clutch: shoot for 25 mph max
2) 20/30 series w 5-7 hp engines (driven unit size also plays a huge factor here in addition to the gear ratio) shoot for 35 mph max, ~28 mph is ideal
3)40 series w 9-13 hp engines 40 mph max

That go kart is a bone stock manco dingo. nothing has been changed. The gear ratio is fine and it will actually take off really fast and climb hills (unless the tecumseh is shot).

hope that makes sense, just need to keep it clear that the big engines w/big torque converters make up for the low end by just piling on the torque, and that is why they can handle the big tires too!


Also, im 99% sure that the belt is shredding because your drive and driven sheaves are rusted. Good thing it is an easy fix..... but it could be spaced out differently, if the drive and driven arent lined up, or parallell, it will wear on the edges of the belt and fray them out too.

Also, just to kind of give a visual of what i am talking about:

The small kart has a 6:1 ratio w/18" tires, goes 33 mph and just has too much torque w/13 hp (with the same ratio, with 30 series and a 5-7 hp engine it would go 35 mph)

the larger orange kart is geared exactly like the dingo in question, (orange one has only 11 hp by the way), and 22" tires so the kart that darian has should perform better than the 2 seat orange one because it has 1 more horsepower, and is less weight.

https://youtu.be/fzNVqrl789o

I wish the video wasnt so muddy to show it, but you get the point. Big engines that go on big karts with big tires are really fun, and will work just fine

 

[landuse]

I still think his gear ratio is not helping the situation at all. It is really borderline IMO

 

[KartFab]

 

[itsid]

Odd to say the least, especially with a 10HP Tec as it's in the manual..

Maybe I should indeed check the manuals again to train more working examples into my calculator... *shrugs*

I still don't see how that's enough torque to accelerate quickly enough to not fray the belt *shrugs*

'sid

 

[Darian1m]

Wow this is very helpful, thanks you guys rock and know your stuff. Indeed my drive and driven sheaves are rusted. Another problem I think may be contributing to the belt burn is that my motor shifts after some rough riding. I have to push the the motor back to tighten some of the slack on the chain. I then torque the mounting bolts up but the motor tends to shift during riding, maybe I am riding it too harsh. I tend to get chain drop after a little bit of off road riding. This engine shift changes the distance slightly between my drive and driven sheaves too which might contribute to the belt sizing being off and getting additional burn. Some more pics below.

So back to the original question, how do I take off my driven sheave?

 

[landuse]

Please post your pics here, instead of linking them

 

[Darian1m]

So I've updated the image links above, hope that helps. Do I need to use some sort of keyed socket to hold the threaded rod in place in order to remove the driven sheave?

 

[Darian1m]

Im still stuck guys, can't get the darn driven sheave off. How do you guys normally do it? I was thinking of building a chain whip tool to lock the sprocket in place but if there is an easier method that would be great.

 

[itsid]

well easiest way I guess would be locking the sprocket (piece of chain tied into a tight loop (with a bolt, not a ziptie) and attaching the other (long) end to something that wont move, either the chassis itself or a piece of wood.

then a quick pass with a wire wheel on the open threads, some pb blaster and patience....(maybe a few repetitions of the last two )
and then a good wrench to loosen the nut.

'sid

 

[KartFab]

What itsid said. There are two nuts. Nuts are removed with wrenches. Since there are two nuts, use one wrench to lock the jackshaft in place, then another to loosen the nut on the opposite end. Can also use locking pliers (vise grips). You are overthinking it.

I just use locking pliers on one nut, rotated it until it hit the frame, then on the nut I wanted removed I just used my socket wrench. I can't remember the size, but I want to say it's 1 1/8". If you don't have a socket that big, you can use a crescent wrench.

 

[Darian1m]

I got it off, KartFab I tried that method but I was afraid of over tightening the opposite nut against the bearing. I ended up throwing the chain back on and locking the 54 tooth sprocket with a rod through body and then the chain kept the driven sprocket in place. That thing was on there tight hope I didn't over stretch the chain. Thanks guys

 

[Darian1m]

KartFab where did you get the parts breakdown above? I just found out the Kart I bought was a green Kart at one point and painted over orange by the last owner. It would be nice to know what exactly I bought and the stock parts/plan.

Looks like this is the kart, just repainted

https://www.powersportsnetwork.com/enthusiasts/new_vehicle_detail.asp?VehicleCode=1932&st=FL&Go=Go

 

[Darian1m]

Never mind I found the manuals, but there are three models. 812, 812-50, and 812E. The parts blow ups all look the same I wonder what the differences are.

 

[Karttekk]

What I did to remove the driven pulley nut was put the kart on jackstands, remove the driver's rear wheel, lay 2 boards down, place a 7/8" open end wrench on the hex axle then rotate the axle until the "box" end of the open end wrench stopped against the boards. Broke out my electric impact gun and spun the nut off. Wouldn't hurt to soak the nut and shaft with some type of penetrating oil before you start. Just have to loosen the engine mounting bolts enough to lift the engine so the driven pulley will clear the kart frame as per another member's suggestion.

 

[Darian1m]

So then it was the chain that kept the driven from spinning? I ended up doing something similar, but in the future I don't want to stretch my chain.