Murray GoCart 440cc sled-cart build

[npetry07]

started off with just a plain old Murray Go cart that i bought and am in the process of modifying and putting a 1977 Astro Sno-jet kawasaki 440cc snowmobile engine in it. I plan to post pictures on here of the build.
So far we have:
-cut off and fabricated the frame to fit the engine. Used a wire feed welder to do this and added 9" onto the back of the cart.
-ordered a longer belt to fit the engine
-connected the clutch straight to the axle
And then of course ran into many design problems the whole way.
Just have to beef up and fix the steering, add a killswitch, modify the roll cage, hook up breaks and throttle, and add a belt tensioner to the belt because the cart has independent suspension that moves up and down.

 

[Doc Sprocket]

Are you using the CVT from the snowmobile, or a centrifugal clutch?

Welcome to the forum!

 

[npetry07]

some sledcart pictures

 

[npetry07]

some more recent pictures

 

[npetry07]

if anyone has any ideas of what belt idler/belt tensioner to use that would be great.

 

[npetry07]

Are you using the CVT from the snowmobile, or a centrifugal clutch?

Welcome to the forum!

clutch system from the sled

 

[Doc Sprocket]

If you are using the sled's CVT, the distance between the driver and driven are critical. If they are allowed to move around independent of each other, I seriously doubt it will work. No matter how hard you try.

 

[npetry07]

If you are using the sled's CVT, the distance between the driver and driven are critical. If they are allowed to move around independent of each other, it won't work. No matter how hard you try.

yeah im sure ill get it figured out. dad is a mechanical engineer, still can use advice though, anything and everything is good

 

[Doc Sprocket]

Hopefully, he can get it worked out, but I just can't picture it happening. If the tensioner is too weak, the belt will slack when the suspension is compressed. Out the window it goes. If the tensioner is too strong, two things will happen- One, it won't idle. It'll take off as soon as you start it. Two, a bump will throw the ratio out.

I suppose it's possible to get it just right- but it may be an engineering nightmare. If it DOES work out for you, do let us know!

One thought- If you can at least get the spring tension in the ballpark, put the anchor end of the spring on an adjuster bolt. Maybe then you can dial it in.

 

[qtband]

I haven't seen the secondary clutch mounted on the axle before. It will be interesting to see if it works out. On my kart, the secondary is mounted to a jackshaft at the exact distance of the original. Then, I have a 9 tooth sprocket on the jackshaft that is connected to a 60 tooth axle sprocket. I'm pretty sure that you're going to have all kinds of gearing issues with your current set-up. Those belts aren't cheap and that horsepower will eat them up if the gearing is wrong.
Do you still have the sled frame? If so, you should utilize the engine mount, including the jackshaft, for your kart. Then run a jackshaft sprocket to an axle sprocket.

 

[Doc Sprocket]

Dang good point, QT. I was so busy examining the tension issue, I totally missed gearing. D'oh!

 

[npetry07]

thanks for all the input ill let you know if anything works/doesnt work!

 

[npetry07]

had some of those ideas in the beginning using a jackshaft but i decided to experiment

 

[npetry07]

Dang good point, QT. I was so busy examining the tension issue, I totally missed gearing. D'oh!

got it to run and work. it doesnt particularly accelerate too fast but once its going its really fast. however i am going to do away with the suspension in the back and set it up so there is little to no belt slack. i took it in a field and hit a bump and the loose belt cut right through the primary clutch. gonna have to spend $100 and buy another. seems to be working fine connected to the axle directly though.