Comet clutching alignment????

DirtyDan

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How close does the primary and secondary sheaves have to be aligned to avoid belt issues????
They are parallel to each other because I’m using a backing plate so there is no issue there.
And I’m trying to run an outboard secondary so the pulleys are aligned better,
But there is still quite a bit of offset between them.
Can you shim between the primary and the crankshaft shoulder to get better alignment???
The comet magnum 44 primary instructions say the clutch must be against the crank shoulder……. 😕D2691965-379C-4436-98C6-12FCA4A17064.jpegD2691965-379C-4436-98C6-12FCA4A17064.jpeg
 

Karttekk

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Looks as though you'll need to use a spacer to move the drive pulley over to align it with the driven. If the instructions say the drive needs to be against the crank shoulder you may need to opt for a different drive or use a spacer anyhow and see how it behaves.
 

redflash

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And if you space out the driver ( which is OK)....then you will need a longer bolt into the crank that equals the width of the spacer. You dont want to lose the threads ( should be 1/2 to 3/4 inch . at least into the crank.

Da Flash
 

DirtyDan

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Thanks for the replies guys……
I think I’m gonna machine a spacer tomorrow at work and possibly even weld the spacer to the rear side of the drive pulley just to eliminate any possible torquing problems. 👍🏻
 

RLS_Underground

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Thanks for the replies guys……
I think I’m gonna machine a spacer tomorrow at work and possibly even weld the spacer to the rear side of the drive pulley just to eliminate any possible torquing problems. 👍🏻
Against the shoulder lol meanwhile a Comet 30 generally comes with a 1" long spacer to sit Against the shoulder to align the sheaves and says the same thing.

You do what you gotta do to line them up. I had to add spacer washers to both shafts to align them and keep the 415 chain from rubbing the tail of the back plate on my 30.

The alignment needs to be within 1mm of dead perfect to minimize premature belt wear and prevent damage
 

Karttekk

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Surprisingly the driver doesn't need to sit too far onto the crankshaft. I've had them where there's only 3/8" or more of crankshaft protruding out from the driver and they held fine. I actually called Dave at Dave's Go Kart Sales to verify this since I thought there was no way it would work. He said he called a clutch manufacturer with one he had like that and they verified it. Strange but true!

https://www.davesgokartsales.com/
 

DirtyDan

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Against the shoulder lol meanwhile a Comet 30 generally comes with a 1" long spacer to sit Against the shoulder to align the sheaves and says the same thing.

You do what you gotta do to line them up. I had to add spacer washers to both shafts to align them and keep the 415 chain from rubbing the tail of the back plate on my 30.

The alignment needs to be within 1mm of dead perfect to minimize premature belt wear and prevent damage
My 520 chain looks like it might rub on either the backing plate or the backside outer lip of the driven sheave.
I think I’m gonna try to machine some of that lip off to free up some space in there for chain deflection.
Hopefully I can get all this figured out tomorrow so I can start fabricating the engine mounting riser plate and start stretching the swing arm 6” to be able to shoehorn the Honda into the frame.
 

RLS_Underground

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My 520 chain looks like it might rub on either the backing plate or the backside outer lip of the driven sheave.
I think I’m gonna try to machine some of that lip off to free up some space in there for chain deflection.
Hopefully I can get all this figured out tomorrow so I can start fabricating the engine mounting riser plate and start stretching the swing arm 6” to be able to shoehorn the Honda into the frame.
That's what my issue was, the #41 sprocket was slightly offset... flip one way it snagged the driven, flipped the other it clattered off the backing. I put a washer in to center the clearance and then shimmed the driver till square
 

panchothedog

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You have room to spare between backing plate and chain. Do you have a spacer between them. Some sprockets have a longer flange on one side compared to the other. Sounds like you have access to machine equipment.
You need a little more room on the clutch side, maybe .100" . Chains flex length
wise all over the place but not much side to side. Your clutch instructions mean
don't try to let it float out on the shaft, as long as you have a solid spacer between the engine and the driver and it is tight against it you will be fine.
You still have a ways to go for proper alingment.
 

madprofessor

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Do all of the shimming and shimmying you want, you'll never get it right with that setup. Either the driver or the driven should be inverted (turned around backwards to the other) so when they shift, they don't move the belt even further out of alignment.
As it sits in the picture, the belt will start out driving a little out of alignment, with the driver being closer to the motor than the driven. Then as speed increases, the driver will move the belt even closer to the motor, and the driven will move the belt even further out away from the motor. It's the backplate thing that confuses everybody.
If you could toss out the backplate, make a separate jackshaft for the driven, and turn it around opposite the driver, the two would work together to keep the belt very close to being in line at all times, regardless of speed. Read ALL OF THE TEXT in the attached link at the top and at the bottom of the page, it will show you all you need to know, pay attention to the diagrams...................
Comet Torque Converter Belts | Go Kart Drive Belts (gokartsupply.com)
 

DirtyDan

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Do all of the shimming and shimmying you want, you'll never get it right with that setup. Either the driver or the driven should be inverted (turned around backwards to the other) so when they shift, they don't move the belt even further out of alignment.
As it sits in the picture, the belt will start out driving a little out of alignment, with the driver being closer to the motor than the driven. Then as speed increases, the driver will move the belt even closer to the motor, and the driven will move the belt even further out away from the motor. It's the backplate thing that confuses everybody.
If you could toss out the backplate, make a separate jackshaft for the driven, and turn it around opposite the driver, the two would work together to keep the belt very close to being in line at all times, regardless of speed. Read ALL OF THE TEXT in the attached link at the top and at the bottom of the page, it will show you all you need to know, pay attention to the diagrams...................
Comet Torque Converter Belts | Go Kart Drive Belts (gokartsupply.com)
This is exactly what I’ve found over the past week of screwing around with it.
The backing plate is the problem………
This is simply no way to properly align these particular clutches with the backing plate.
I was trying to avoid alignment issues by using a backing plate, but a jackshaft system is gonna as be needed with these Comet 44 series clutches.
Ugh……
 

madprofessor

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Can't stress enough the importance of what GKS shows on the link I attached above................Just scrolling down the page shows the way 30-series and CAT99 series asymmetric CVT's (first 2 diagrams) have the spring-loaded side of the pulleys on the same side as they are when on a backplate, and how all the rest are symmetric and have the spring-loaded sides facing opposite of each other.
There is absolutely no choice with asymmetric CVT's about which way to face the pulleys, one side of each is basically flat and that has to be on the same side. Symmetric CVT's need to be opposite of that, but many folks try to mount them the same (like on a backplate) and shim one or both so that the misalignment kind of splits between idle and full power. Half out of line when sitting still, and shifting to half out of line to the other side at full power. The only time they're ever in line is halfway through their shifts.
Comet Torque Converter Belts | Go Kart Drive Belts (gokartsupply.com)
 

DirtyDan

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Can't stress enough the importance of what GKS shows on the link I attached above................Just scrolling down the page shows the way 30-series and CAT99 series asymmetric CVT's (first 2 diagrams) have the spring-loaded side of the pulleys on the same side as they are when on a backplate, and how all the rest are symmetric and have the spring-loaded sides facing opposite of each other.
There is absolutely no choice with asymmetric CVT's about which way to face the pulleys, one side of each is basically flat and that has to be on the same side. Symmetric CVT's need to be opposite of that, but many folks try to mount them the same (like on a backplate) and shim one or both so that the misalignment kind of splits between idle and full power. Half out of line when sitting still, and shifting to half out of line to the other side at full power. The only time they're ever in line is halfway through their shifts.
Comet Torque Converter Belts | Go Kart Drive Belts (gokartsupply.com)
Yeah…… the backing plate is going in the garbage and a FNR gearbox is on the way.
I was trying to avoid any unnecessary fabrication by using the backer.
I’ll just have to extend my engine mount out further to accommodate the reverse gearbox I guess.
Anyone need a brand new backing plate????? 😂
 

Snaker

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Dirty Dan. Any chance you could show a couple close up photos of the driven pulley on the shaft?
With bolt, without bolt, where the end of the shaft ends?

Can you try to turn the pulley around with the fixed sheave outboard to see if it fits, or what would keep it from fitting?
I wish I could see exactly what you have there.

Backing plates are actually a good thing.
They hold a precise c-c distance and give a lot of structural support.
But you can't compromise the pulley alignment to use it.
A backplate would be worth it even if you had to get a new driven shaft made in order to position things properly.
 

Denny

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Try turning around the primary clutch on the engine and flipping the sprocket behind the secondary clutch and see if that doesn’t buy you some more room.
 

RLS_Underground

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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
 

RLS_Underground

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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.

The problem is the majority of clones use a stepped shaft (5/8-15mm) and the drivetrain parts only fit on the 15mm end. Then there's the issue that most of the shafts use a circlip on the back to keep it in the bearings.
The step also eliminates the need for a spacer (between the bearings) and accidental over tightening of the bearing preload or pulling the shaft through making the clip pop off.
 
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Karttekk

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I picked up a 30 Series for a Carter Super Wheels kart I just sold, the vendor said I could use it but I would have to drill an additional hole or change the spring direction or both, dunno. I ended up with a 20 Series setup that worked fine. It was an odd setup though. The kart shipped with a live axle but the axle sprocket was mounted on the driver's rear wheel with a keyed hub that turned the whole axle.
 

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