Comet 40 Series setup problem

[MTopp]

Hey all, got this Manco 13hp kart put back together a couple months back and got a new belt, noticed it seemed to be wearing a bit excessively, then noticed what the pictures show. The belt is lined up nice when not moving, but as the clutches engage, they each pull a different way. Any opinions?

I assume this is how they had it stock as it has the yellow spring in the driven and that's how it was mounted when I got it, but seems not ideal.

I'm probably going to be modifying the kart to have front and rear suspension so I hope I can then flip the driven and use a red spring or at the least move it as close towards to the engine as I can.

 

[karl]

With the driven clutch run like that, it needs to float on the jackshaft freely, about an inch, to maintain alignment

With the driven flipped , and normal red spring, it can be fixed to the shaft, as that is the intended orientation of the clutch.


PS- Ahh I see the backplate, thats no fun. The 40 series was never intended to mount on a backplate (despite what GoPowerSports wants you to think) You could try flipping the motor's driver clutch around, never tried it myself , but I have seen it done before.

 

[itsid]

yeah that stupid backplate really is nothing but a huuuge PITA!

unfortunately however,
that appears to be the original setup of the 392/393 Mancos
(judging by the size of the plate)
I'm assuming your driven sits on the original jackshaft plate, correct?

Since Yes, Manco tried the exact same thing and it was a giant pain as well.
but since it only slows the kart down and wears the belt it wasn't their problem
(fun fact they did it right in 1992 and wrong in 1998 so much for learning...)

Ah well.. try -as karl said- to flip the driver unit inside out;
should work (yellow spring should still be correct )

'sid

 

[MTopp]

With the driven clutch run like that, it needs to float on the jackshaft freely, about an inch, to maintain alignment

With the driven flipped , and normal red spring, it can be fixed to the shaft, as that is the intended orientation of the clutch.


PS- Ahh I see the backplate, thats no fun. The 40 series was never intended to mount on a backplate (despite what GoPowerSports wants you to think) You could try flipping the motor's driver clutch around, never tried it myself , but I have seen it done before.

yeah that stupid backplate really is nothing but a huuuge PITA!

unfortunately however,
that appears to be the original setup of the 392/393 Mancos
(judging by the size of the plate)
I'm assuming your driven sits on the original jackshaft plate, correct?

Since Yes, Manco tried the exact same thing and it was a giant pain as well.
but since it only slows the kart down and wears the belt it wasn't their problem
(fun fact they did it right in 1992 and wrong in 1998 so much for learning...)

Ah well.. try -as karl said- to flip the driver unit inside out;
should work (yellow spring should still be correct )

'sid

That's actually not a back plate, its just a plastic splash guard that came on the kart so I figured I'd leave it. I could let the driven have about an inch of play, but then wouldn't that wear out the jackshaft or the clutch or not really? Seems I would need to keep it greased very well.

---------- Post added at 09:34 PM ---------- Previous post was at 09:33 PM ----------

I could also space the driver clutch out more but that seems like it would add more stress on the engine shaft and the driver.

---------- Post added at 09:35 PM ---------- Previous post was at 09:34 PM ----------

Or could space the driver a small amount and the driven a small amount in, better for it to be aligned at speed than idling, no?

 

[itsid]

I think the easiest way to go would be to find the jackshaftplate of
a Manco 389 Dingo
that was still mounted correctly (up until 1995 at least)

the part numbers for matching plates are
9334-2 or
6365-2
I think the one of a 611 might also fit that'd be part #
6676-2

you can look up the manuals for each of these
online
at americanlandmaster.com/manuals/fun-kart-manuals/

maybe you find more matching plates,
the sprockets will have to move to the other side in order to make room for the cam,
but that shouldn't be much of a problem really

the driver MUST NOT float! but it can be spaced out if your crankshaft is long enough ..
but frankly very few are

So, the correct way IMHO is to fix the brain fart Manco added in the late nineties and flip the driven back how it belongs.

And the only other maybe viable option is to instead flip the driver.
We haven't had much reports about a flipped driver working well and reliably though.
it's advertised it's been tried.. but I cannot remember any single one
actually calling it a success (or a failure for that matter) *shrugs*

I'd try and judge myself .. not much to loose but time, right?

driven float must be INBOARD by 7/8"
I bet there's no room for it to float that way tbh
since frankly that's maybe 1/16" less than you'd need to flip the driven the right way around anyways
So a floating driven is maybe a viable solution, but just in theory really.

if you're willing to cut and weld,
you can also cut an inch off the jackshaft tube that holds the bearings
then weld it back on the opposite side.
to essentially emulate the style of the 'good' jackshaft plates
(or make your own from scratch since that wouldn't leave you without any if you mess up)

'sid

PS the problem with a misaligned belt at idle is that the belt will catch and the kart will creep forward.
so both is actually bad

 

[MTopp]

I think the easiest way to go would be to find the jackshaftplate of
a Manco 389 Dingo
that was still mounted correctly (up until 1995 at least)

the part numbers for matching plates are
9334-2 or
6365-2
I think the one of a 611 might also fit that'd be part #
6676-2

you can look up the manuals for each of these
online
at americanlandmaster.com/manuals/fun-kart-manuals/

maybe you find more matching plates,
the sprockets will have to move to the other side in order to make room for the cam,
but that shouldn't be much of a problem really

the driver MUST NOT float! but it can be spaced out if your crankshaft is long enough ..
but frankly very few are

So, the correct way IMHO is to fix the brain fart Manco added in the late nineties and flip the driven back how it belongs.

And the only other maybe viable option is to instead flip the driver.
We haven't had much reports about a flipped driver working well and reliably though.
it's advertised it's been tried.. but I cannot remember any single one
actually calling it a success (or a failure for that matter) *shrugs*

I'd try and judge myself .. not much to loose but time, right?

driven float must be INBOARD by 7/8"
I bet there's no room for it to float that way tbh
since frankly that's maybe 1/16" less than you'd need to flip the driven the right way around anyways
So a floating driven is maybe a viable solution, but just in theory really.

if you're willing to cut and weld,
you can also cut an inch off the jackshaft tube that holds the bearings
then weld it back on the opposite side.
to essentially emulate the style of the 'good' jackshaft plates
(or make your own from scratch since that wouldn't leave you without any if you mess up)

'sid

PS the problem with a misaligned belt at idle is that the belt will catch and the kart will creep forward.
so both is actually bad

Ah yea, I'll figure something out. I'm going to be cutting and welding some of it out to add the ATV rear swingarm suspension - so moving the sprocket may not be possible unless I run a dual jackshaft setup which wouldn't be too bad.

 

[itsid]

please don't cut the Dingo to mount an ATV suspension to the rear..

it might sound like a good idea now,
but you will regret that eventually
(at least when you're trying to sell it one day)

Dingos a sought after and beloved heavy duty yard karts..
they get rarer and more expensive every year.
cutting one up is almost blasphemic!

swapping a part that can easily swapped back is perfectly okay.. hence
making a new jackshaft plate over cutting the original,
cutting the plate over cutting the chassis as a whole
since the plate can be replaced, the chassis cannot as easily

Your kart, but I'd strongly suggest to not cut that poor thing

'sid

 

[MTopp]

please don't cut the Dingo to mount an ATV suspension to the rear..

it might sound like a good idea now,
but you will regret that eventually
(at least when you're trying to sell it one day)

Dingos a sought after and beloved heavy duty yard karts..
they get rarer and more expensive every year.
cutting one up is almost blasphemic!

swapping a part that can easily swapped back is perfectly okay.. hence
making a new jackshaft plate over cutting the original,
cutting the plate over cutting the chassis as a whole
since the plate can be replaced, the chassis cannot as easily

Your kart, but I'd strongly suggest to not cut that poor thing

'sid

Well I'd really like to have a kart/mini-buggy with front and rear suspension, I could probably add the rear suspension with out cutting up the rear frame too much. Up in the northeast here there's at least 10 dingo frames listed on facebook at the moment, not a ton with "full cage" though, and none that are 13hp karts.

I see where you're coming from, but at the same time no one in my area really cares for these karts and there's no real demand for them. They're really not worth much except to the few people who like them.

I could make a full suspension buggy from scratch (but would be a lot of trial and error and I dont have the tools at home), keep this gx390/40 series and sell the frame, but would save me time fabricating to mod this kart frame.

I don't know though, I'm still trying to decide what to do - whatever I do, I hope to do it very clean so it'll look stock. The hard frame no suspension is kind of useless with this much power.

 

[itsid]

Well...
your kart your choice..
and if you cut it up, I'll just silently whimper a bit for another one being lost forever though

Frankly the last ATV rear fused Dingo I've seen was just terrible,
that huuuge overhanging axles are just not exactly made to support a kart IYAM.

I always wonder why one wants that tbh (it's screaming "bent axle in 5..4..3")
when there are plenty of karts with full suspension
with the axles properly supported for the karts weight..
like the Yerf dog 42101 or a Manco 906, Murray Kilowatt and so on and so forth.

'sid

 

[MTopp]

Well...
your kart your choice..
and if you cut it up, I'll just silently whimper a bit for another one being lost forever though

Frankly the last ATV rear fused Dingo I've seen was just terrible,
that huuuge overhanging axles are just not exactly made to support a kart IYAM.

I always wonder why one wants that tbh (it's screaming "bent axle in 5..4..3")
when there are plenty of karts with full suspension
with the axles properly supported for the karts weight..
like the Yerf dog 42101 or a Manco 906, Murray Kilowatt and so on and so forth.

'sid

Well I already have the atv parts laying around I would either use them or I would just build a tube swingarm like some karts come with. Probably is better tho like ya said to build one, stronger and parts are much cheaper and easier to get.

 

[Joe-405]

If I remember correctly I just spaced my driver out on the one I had. It needs to be straight at full rpm to not cause premature belt wear.