Belt change/adjustable jackshaft? Quick question...

[TNThomas]

Hello folks, I am currently wrapping up a Grand Daddy build. Im working on the swingarm, and about to start welding steel in for the engine support/jackshaft support.
I was thinking last night, with everything bolted up, how the heck do you change/put on your belt? I will be using one of the standard 1/4" thick engine mounting plates. How those are built, there is a little bit of room, an inch or so, to slide your engine once you loosen the bolts. This would help to change the belt, but is that amount of sliding enough? Does anybody build/mount their jackshaft on a similar sliding setup to help with this? Ideally, that little bit of sliding will be enough. I would rather not build in an adjustable Jackshaft due to the possibility of getting loose. I have never actually ridden a go-kart or dune buggy, and only changed a snowmobile belt once. I just fake like I know what I am doing.

 

[madprofessor]

I would rather not build in an adjustable Jackshaft due to the possibility of getting loose.

I'm picturing only 2 schools of thought there, adjustable jackshaft, or a massively strong springed tensioner for a jackshaft fixed to the motor mounting plate. Not even sure if you can properly spring tension the variable position belt if you tried. I personally want everything adjusted to my preference, not the amount dictated by a spring and fixed leverage. So for me, adjustable only..............
Not a lot of real schools of thought on that as well. Slide the jackshaft in slots to tension the chain to the axle, then slide the motor in slots to tension the belt. Or build a double-slotted motor mounting plate for the whole plate to slide for chain tension to a jackshaft fixed to the plate, and then slide the motor in slots of its own for the belt tension.

 

[TNThomas]

I'm picturing only 2 schools of thought there, adjustable jackshaft, or a massively strong springed tensioner for a jackshaft fixed to the motor mounting plate. Not even sure if you can properly spring tension the variable position belt if you tried. I personally want everything adjusted to my preference, not the amount dictated by a spring and fixed leverage. So for me, adjustable only..............
Not a lot of real schools of thought on that as well. Slide the jackshaft in slots to tension the chain to the axle, then slide the motor in slots to tension the belt. Or build a double-slotted motor mounting plate for the whole plate to slide for chain tension to a jackshaft fixed to the plate, and then slide the motor in slots of its own for the belt tension.

Good point on erring on the "adjustable" side with the jackshaft. Thanks for the input. Two pros of this that I just thought of are variances in belt lengths and chain lengths, especially if I experiment with different-sized sprockets. I'll probably buy some sort of adjustable plate and mount the jackshaft to that. That way I can slide it back and forth like mentioned, in addition to being able to slide the engine forward and backwards. One Idea I had was to have two different-sized sprockets on both the jackshaft and axle. One with a highish gear ratio, my main combo for off-roading/having fun. But a second sprocket on both jackshaft and axle with a much lower gear ratio for higher speeds. All I would need is a second dedicated chain (for unique chain length), and likely a second dedicated belt (if the jackshaft needs to slide). That way if I need to run from our cabin, into town, I can make the 30-mile drive at much higher speeds by just swapping the belt and chain. Not much weight difference, and a completely different speed/torque range.

The double sliding should make belt changes a breeze too.

 

[Denny]

You will just change the belt like you do on a snowmobile. Over the secondary and off the primary. Way easy! I would fix mount everything but you will need a way to tension the chain.

 

[panchothedog]

I have a 40 series torque converter on one of my karts. Smaller than yours, but similar. To install the belt, slip the belt over both pullies ( clutches ) and slip both onto their shafts at the same time. Seeing how there is slack in the belt when the clutches are in the relaxed position, this is easier to do then it sounds.
it is very close, but if you have the right belt for the distance between the clutches you will be able to pull them far enough apart and slip them on.