Murray Kilowatt style swing arm vs standard swing arm

[70Cobra]

Hi Guys,

Looking for some advice from those who have driven the Murray Killowatt (or similar style swing arm) and also a standard yard kart with the engine mounted on the swing arm.

Did it make a lot of difference in how they both rode?

I have a yerf 3203 (I think!) which has a quad front suspension on it, single seat, fully welded and modified cage, and a stage 2 Predator. I'm looking to do a stage 3/4 build to the predator.

It is ridden on my property and the woods, which are both hilly and bumpy. Just wondering if it is worth the hassle to convert it to the Killowatt style swing arm, where the engine is on the main buggy/kart frame.

My trails end up having some decent ruts from where we power slide around corners etc. If it would make a difference to how it handled those sections I would consider modifying my yerf. It wouldn't be overly difficult, besides working out a chain tensioner but I don't want to go through all the work if it is not going to wow me.

 

[Denny]

It probably won’t wow you. As long as you are sticking with a lighter engine it will be fine. The truth is as long as the suspensions are set up properly there should be no difference.

 

[Dingocat]

It probably won’t wow you. As long as you are sticking with a lighter engine it will be fine. The truth is as long as the suspensions are set up properly there should be no difference.

And carb.

 

[madprofessor]

besides working out a chain tensioner

Very little chance that you can work out a successful chain tensioner that will prevent skipping for a chain that constantly loosens and tightens because of the swingarm going up and down. If you tried, the tensioner MUST BE ON THE BOTTOM side of the chain, the side that goes slack under load while the top side tightens up. Look at construction pic below to see the best way to do it, where no tensioner is required at all, even where theoretical max travel is 2' at the rear bumper. (The rigid one you see is only for the original adjustment, since nothing about the secondary chain slides on its mounts like the engine does.)
My setup started with a single 44.625" x .75" shaft, that remained in one piece until all of the pillow blocks were solidly mounted. That's how you do it, keeping the swingarm and jackshaft in perfect alignment with each other. I cut the shaft into 3 pieces only afterward so that only the jackshaft portion would spin with the engine. The swingarm pivots only move like the hinges on your front door.
NOTE: Just ignore my "cantilevered diminishing resistance swingarm suspension" setup. You only need to mount shocks in the standard direct setup like on any kart.

 

[70Cobra]

It probably won’t wow you. As long as you are sticking with a lighter engine it will be fine. The truth is as long as the suspensions are set up properly there should be no difference.

Thats what I figured, thanks.

 

[70Cobra]

Very little chance that you can work out a successful chain tensioner that will prevent skipping for a chain that constantly loosens and tightens because of the swingarm going up and down. If you tried, the tensioner MUST BE ON THE BOTTOM side of the chain, the side that goes slack under load while the top side tightens up. Look at construction pic below to see the best way to do it, where no tensioner is required at all, even where theoretical max travel is 2' at the rear bumper. (The rigid one you see is only for the original adjustment, since nothing about the secondary chain slides on its mounts like the engine does.)
My setup started with a single 44.625" x .75" shaft, that remained in one piece until all of the pillow blocks were solidly mounted. That's how you do it, keeping the swingarm and jackshaft in perfect alignment with each other. I cut the shaft into 3 pieces only afterward so that only the jackshaft portion would spin with the engine. The swingarm pivots only move like the hinges on your front door.
NOTE: Just ignore my "cantilevered diminishing resistance swingarm suspension" setup. You only need to mount shocks in the standard direct setup like on any kart.

Your cart is basically the same set up as the Murray Killowatt, which uses a jackshaft pivot point.