Comet clutching alignment????

[Rat]

with access to a lathe or machine shop you could have the Id's turned out 0.89 and use a straight 5/8 shaft to put the drive gear behind the back plate. That would also require a 5/8 ID spacer between the bearings though

 

[Snaker]

Personally I'd just get a different shaft so that the sprocket is behind the backing plate, and the pulleys become near perfectly aligned by that default, it would most likely require some minor shimming to the driven, easier to shim by a few 16th's than reconfigure the entire assembly

With that orientation the pulleys will not be near perfectly aligned.
During upshift the belt will be moving inboard at the front while its moving outboard at the rear.
During downshift it will be the opposite.

Some people claim that the driven pulley will "float" laterally to follow the drive pulley.
There may be some amount of that but I believe it would be minimal.
The pulley, under tension, will resist being moved with that kind of leverage and will for sure lag in alignment, if it moves at all.
In the snowmobile world, some claimed that allowing more than spec'd slack of the driven pulley mounting would let it float a small amount, keeping better alignment and saving belts.
That was to correct for the engine twisting on the mounts and even the success of that very small amount was debatable.

 

[Snaker]

The illustrated diagrams from Comet show the driven mounted inboard. Maybe the back plate (in this situation) should be eliminated. I thought the driven on 20 and 40 Series torque converters always mounted inboard. Not familiar with either so I could be way off there.

https://www.eccarburetors.com/assets/images/Comet-44-Magnum-Manual.pdf

I have never seen any setup description from Comet referring to a backplate on the symmetrical systems.
If its out there I would love to see it.
Maybe mistaken but, I think these backplate kits are from someone other than the CVT mfgrs, possibly copying off the asymmetrical setups.
And if so, those backplate kits may be poo.

Still, with proper design, a backplate setup would be fantastic, even on the symmetrical CVT's.

 

[Rat]

With that orientation the pulleys will not be near perfectly aligned.
During upshift the belt will be moving inboard at the front while its moving outboard at the rear.
During downshift it will be the opposite.

Some people claim that the driven pulley will "float" laterally to follow the drive pulley.
There may be some amount of that but I believe it would be minimal.
The pulley, under tension, will resist being moved with that kind of leverage and will for sure lag in alignment, if it moves at all.
In the snowmobile world, some claimed that allowing more than spec'd slack of the driven pulley mounting would let it float a small amount, keeping better alignment and saving belts.
That was to correct for the engine twisting on the mounts and even the success of that very small amount was debatable.

That's all horse$hit because the rear sheaves of both the driver and driven are fixed... only the outer move. The driver moves inboard lifting the belt, and the belt forces the driven outboard to compensate...there is no latteral movement of the belt at all

 

[Denny]

That's all horse$hit because the rear sheaves of both the driver and driven are fixed... only the outer move. The driver moves inboard lifting the belt, and the belt forces the driven outboard to compensate...there is no latteral movement of the belt at all

He is right RLS. On a normal 40 setup which was designed for Manco the secondary is supposed to face inboard. Or misalignment occurs.

 

[Snaker]

That's all horse$hit because the rear sheaves of both the driver and driven are fixed... only the outer move. The driver moves inboard lifting the belt, and the belt forces the driven outboard to compensate...there is no latteral movement of the belt at all

Upgrading to a 40 Series Torque Converter on a Manco Dingo Go-kart - YouTube

Go to 17:00
Say your sorry

 

[Karttekk]

According to Comet, the back plate cannot be used since the driven needs to run inboard. This necessitates a jackshaft.

 

[Karttekk]

Read the comments in the comment section below the linked video. It's stated a few times about either the driven needs to run inboard or the driver needs flipped around. Good call Denny.

 

[Snaker]

40 series torque converter installation - YouTube

Here's one of the better explanations that I have seen on Utube for flipping the drive pulley.
Starting at 5:50
He doesn't show a view of belt alignment though.
People have sworn up and down that flipping the driver positions the belt way too far outboard for the driven to match so I don't know.

 

[panchothedog]

Hey Dirty Dan, can't believe I didn't notice you are running a 40 series unit. Take your drive clutch ( the one on the engine ) and flip it around 180 degrees,
so the fat part of the clutch is inboard. It will fix your alignment problem. I am running a 40 series torque converter on one of my karts, I bought the whole setup from O. M. B. Warehouse and that is the way they told me to mount it.
It works great, and it helped my alignment problem also. With the symmetrical
belt it makes no difference which way the driver is facing. You were bad mouthing the backing plate and believe me that is not your problem. Turn it around and get driving.

 

[Trevinator]

just shim out the primary clutch until the belt is parallel to the sheaves. my 40 series kit came with washers to space out the primary. might need a longer bolt, but its no big deal. dont try to reinvent the wheel here, just shim it out with washers!

 

[Denny]

just shim out the primary clutch until the belt is parallel to the sheaves. my 40 series kit came with washers to space out the primary. might need a longer bolt, but its no big deal. dont try to reinvent the wheel here, just shim it out with washers!

No! That is the exact wrong thing to do!

We told him how to fix it correctly already.

 

[Trevinator]

No! That is the exact wrong thing to do!

We told him how to fix it correctly already.

that is a comet 44c clutch and it can not be simply turned around. it has a flat end with the hole just big enough for the bolt to go through. if the belt is parallel to the sheaves, it will be fine. that is how mine is setup and works with zero issue. the chain is between the secondary and the backing plate just as the op's is. might not be the 'ideal' alignment, but the belt is perfectly happy as is.

 

[Denny]

If he puts a regular old 40 driver on there and sends back that useless 44 he will be golden. Just wait until he melts the pucks from heat. Then you just throw it all away. Joe 405 on here did that years ago with his drag mini bike. Melted them on his first or second pass I believe.

 

[Trevinator]

If he puts a regular old 40 driver on there and sends back that useless 44 he will be golden. Just wait until he melts the pucks from heat. Then you just throw it all away. Joe 405 on here did that years ago with his drag mini bike. Melted them on his first or second pass I believe.

no issue with my 44c and 420 predator powered go kart. the 44c works way better and more reliably than the 40 series for me. the 40 series always throws the weights out of the track. i also got more top speed from the 44c vs the 40 series.

 

[Karttekk]

The most important or one of the most important parts of this video start at 6:50. The driven spring needs to be a reverse spring if running the driven outboard. Dirty Dan will or should be okay with the backplate as long as the correct spring is installed in the driven.

 

[Snaker]

that is a comet 44c clutch and it can not be simply turned around. it has a flat end with the hole just big enough for the bolt to go through. if the belt is parallel to the sheaves, it will be fine. that is how mine is setup and works with zero issue. the chain is between the secondary and the backing plate just as the op's is. might not be the 'ideal' alignment, but the belt is perfectly happy as is.

Run time and user experience is pretty much the ultimate proof.
I wouldn't say its happy that way.
I see it as being ok with running a flat tire because the other three still roll.
The driver design you mention is a big key factor.

So to recap:
30 series works with a backplate because its asymmetrical and designed for a backplate.
40 series is claimed to work with a backplate if the driver is flipped
44 series is claimed to not be able to flip the driver, so the driven would have to be flipped, somehow. Or leave it compromised and see what happens.

 

[Snaker]

The most important or one of the most important parts of this video start at 6:50. The driven spring needs to be a reverse spring if running the driven outboard. Dirty Dan will or should be okay with the backplate as long as the correct spring is installed in the driven.

Those springs are available and along with the switching to the other ramps, will allow the driven to spin in either direction.

 

[madprofessor]

Can't swear I didn't miss a post that said it, but I didn't notice a post saying the simple truth about backplates on symmetric CVT"s.................
..............that the amount of shaft length available on the driveshaft of the motor, or of the jackshaft built into the backplate, is never plenty enough for feeling confident when either the driver or the driven is turned opposite as is needed on symmetric units.
It's like being happy that the chosen shaft doesn't even reach the outside of the inverted pulley, much less have any extra length. Folks who are all OCD like myself just can't deal with that, I want every possible shaft/pulley contact space utilized, regardless of the 1/4" piece of keystock or anything else. If the shaft doesn't reach the end, my OCD self won't use it.

 

[Rat]

Can't swear I didn't miss a post that said it, but I didn't notice a post saying the simple truth about backplates on symmetric CVT"s.................
..............that the amount of shaft length available on the driveshaft of the motor, or of the jackshaft built into the backplate, is never plenty enough for feeling confident when either the driver or the driven is turned opposite as is needed on symmetric units.
It's like being happy that the chosen shaft doesn't even reach the outside of the inverted pulley, much less have any extra length. Folks who are all OCD like myself just can't deal with that, I want every possible shaft/pulley contact space utilized, regardless of the 1/4" piece of keystock or anything else. If the shaft doesn't reach the end, my OCD self won't use it.

There's medication and therapy for that... js