Help me fix this mess.

[Mccartercar]

I bought this Murray Hard Drive on a whim at a gas station. I cant find any cracks in the frame and the motor runs but she needs some love. Im thinking of going with a 30 series setup and get rid of all this welded garbage. Im not sure if a mounting plate will fit on the engine or if the bolt holes will mount a 30 series. Any ideas on how I should redo the TC on this monstrosity?

 

[USAMAC]

I'm looking forward to the experienced folk here chiming in soon.. I'm too much of a noob to add much value, but I will tell you if it were mine I'd be inspecting this weld pretty good to ensure it's not in need of more.

 

[Functional Artist]

It looks like it needs cleaned up & lubed
...but, that looks like pretty standard "jack shaft" (gear reducer) set up (so the rear sprocket is not the size of a "dinner plate")
...&/or what's the problem?

You say the "engine" (motors are electric) runs
...but, does it "go"?

 

[Mccartercar]

It looks like it needs cleaned up & lubed
...but, that looks like pretty standard "jack shaft" (gear reducer) set up (so the rear sprocket is not the size of a "dinner plate")
...&/or what's the problem?

You say the "engine" (motors are electric) runs
...but, does it "go"?

The way it is now the small sprocket on the jackshaft is near stripped because they left no way to tension the chain when they solid welded the jackshaft housing. So I could take a link out but id still need to replace that sprocket, thats crudely welded to that jackshaft . Also Ive never seen a small centrifugal clutch on a motor that size and it is near rubbish from what I can tell or near the end of its life. I was just thinking of going simpler and using a mounting plate and totally cutting out the jackshaft altogether.

 

[Mccartercar]

I'm looking forward to the experienced folk here chiming in soon.. I'm too much of a noob to add much value, but I will tell you if it were mine I'd be inspecting this weld pretty good to ensure it's not in need of more.

View attachment 129477

I spotted that and I poked at it a bit. I will clean it when I do a tear down and see whats what. Gussets maybe if need be?

 

[Functional Artist]

The way it is now the small sprocket on the jackshaft is near stripped because they left no way to tension the chain when they solid welded the jackshaft housing. So I could take a link out but id still need to replace that sprocket, thats crudely welded to that jackshaft . Also Ive never seen a small centrifugal clutch on a motor that size and it is near rubbish from what I can tell or near the end of its life. I was just thinking of going simpler and using a mounting plate and totally cutting out the jackshaft altogether.

Um...OK
I didn't see the "bad" sprocket (that's why I asked what the problem was)

I guess they shoulda just used them holes & bolted 'er down
...so, it woulda been adjustable

Also,
IIRC, most "engines" over ~8HP require a 40 series TAV

 

[Mccartercar]

Um...OK
I didn't see the "bad" sprocket (that's why I asked what the problem was)

I guess they shoulda just used them holes & bolted 'er down
...so, it woulda been adjustable

Also,
IIRC, most "engines" over ~8HP require a 40 series TAV

Alright, i guess ill look at 40 series stuff onstead if you really think it needs it. I was thinking 40 series really werent "needed" until 13hp where the torque goes up more than the hp. Thanks.

 

[Denny]

No, at 9 hp you should seriously think 40 series. With a big block you also have the additional torque to deal with.

 

[Mccartercar]

No, at 9 hp you should seriously think 40 series. With a big block you also have the additional torque to deal with.

Thanks for the response. Ok with that settled, should I just get a mounting plate and delete the jackshaft or move the jackshaft and use it for the driven? Also I have no idea what size sprocket the axle is using or what size chain? Is it typically a different tooth count from centrifugal to TC? Tips?

 

[Denny]

You will need to retain the jackshaft. You will also need to move it. It will also need a different and longer shaft. You will also need a 40 series kit, however do not use the belt the kit comes with its junk. Genuine Comet only on the belt. You will also need a 60 tooth axle sprocket, and a 10 tooth jack shaft sprocket. You can weld right? If not learn, or make friends with a welder.
Go to the Gokart Supply website and read up on the 40 series cvt, what parts they use and how to set it up properly. Then come back and ask more questions if needed. Take lots of pictures and comeback with a plan. We got your back!

 

[Mccartercar]

You will need to retain the jackshaft. You will also need to move it. It will also need a different and longer shaft. You will also need a 40 series kit, however do not use the belt the kit comes with its junk. Genuine Comet only on the belt. You will also need a 60 tooth axle sprocket, and a 10 tooth jack shaft sprocket. You can weld right? If not learn, or make friends with a welder.
Go to the Gokart Supply website and read up on the 40 series cvt, what parts they use and how to set it up properly. Then come back and ask more questions if needed. Take lots of pictures and comeback with a plan. We got your back!

Ok. Ill be back.

 

[ONE-EYE]

Those 2 holes on the back of your engine mount plate are actually for the jackshaft. The jackshaft mount actually used all 6 slots but the other 4 are mounted under the engine itself. It can be a pain when time to change the oil pending on where your plug is. The sprocket shouldn't be welded to the jackshaft. Normally there's a key that slides into the shaft. The clutch on there now seems a bit far away from the motor. Might be what's making it sound funny. I'm currently taking out my jackshaft too but if you did want that setup, BMI karts has the jackshaft mount fully assembled for $50. You could still run a TAV with it either way.

 

[madprofessor]

You could always make your own chain tensioner for your secondary chain. Attaching a pic of adjuster for steering chain, you can see the black roller and the adjuster bolt to its left. A second pic of adjuster for a really long secondary chain, made it bigger than needed, but the idea here is to show you can make your own.

 

[Mccartercar]

You could always make your own chain tensioner for your secondary chain. Attaching a pic of adjuster for steering chain, you can see the black roller and the adjuster bolt to its left. A second pic of adjuster for a really long secondary chain, made it bigger than needed, but the idea here is to show you can make your own.

Ive been thinking about the chain tensioning too. I like your setups and may lean towards that if my other plan of attaching the motor

 

[madprofessor]

Sorry, should have mentioned spring tensioners..............They're not the best thing you can use. All they're good for is keeping the side of the chain that goes slack when you pour on the throttle from jumping off the sprockets. They can't replace good firm chain tension.
The pic of the steering chain's black roller, well it's actually from a spare spring tensioner, robbed it off there for what you see, a roller held tight in place by an adjuster bolt.

 

[Mccartercar]

Sorry, should have mentioned spring tensioners..............They're not the best thing you can use. All they're good for is keeping the side of the chain that goes slack when you pour on the throttle from jumping off the sprockets. They can't replace good firm chain tension.
The pic of the steering chain's black roller, well it's actually from a spare spring tensioner, robbed it off there for what you see, a roller held tight in place by an adjuster bolt.

Thanks for that insight.

 

[Mccartercar]

Its taken me a while to get back to her. Ive now got it disassembled and seeing what I find. Atm I have a crack in the frame, two stuck bearings, a stuck axle sprocket, a stuck centrifigual clutch, a gummed up gas tank and carb, broken seat frame, loose steering, hit or miss brakes, and multiple other things on the to do list including cabling.
Everything thats stuck will simply not budge. Im currently letting it get penetrating oil everywhere and generally cleaning and prepping here and there.
On the pictures of the bearings, the sleeve that the bearing rides on is seized to the axle with no set screws in place. The sprocket thats mounted on the brake drum sleeve is also seized on the axle. Note how it looks beat to death, not my work. The steering gear pics I put a spacer behind the plate representing how small the hole should be versus how big and out out round it is and how the bow gear is warped in both directions with slack in the bushing. I plan on getting it all sand blasted once i get the axle off.
Ive got my work cut out for me. Ive decided to use an engine mount for the 40 series driven pulley and mount the engine on a hinge on the front and an adjustable base in rear for chain slack issues. I should be able to get high enough and far enough forward with the engine to allow the driven to attach to the axle without interfering with the rear frame brace above the axle. Thoughts?

 

[madprofessor]

The sprocket thats mounted on the brake drum sleeve is also seized on the axle. Note how it looks beat to death, not my work.

Wow. For a second there, I was thinking "He's trying to drive a sprocket off of an axle that's welded to the axle." Beat to death is a very kind way for you to describe the malefactor's work.

to allow the driven to attach to the axle

What do you mean by "attach to the axle"? I know you can't mean you'd attach the driven pulley to the axle and run the thing as a pure belt drive.

 

[Functional Artist]

Well, I guess you "nailed it" when you named this thread

I'd first evaluate the rear axle ta see if it's even worth trying to save (bent, beat up, keyway damaged etc.)
...if it's too "far gone" ya can usually get a brand new one for under $50.00

If your gonna try-n-save it, you'll probably have to "split" them bearing races (& anything else that's stuck & no longer usable) ta get 'em off)
...just use a cut off tool (or hack saw if possible) to cut thru one side (without damaging the axle underneath) & then, gently pry it off

 

[Mccartercar]

Wow. For a second there, I was thinking "He's trying to drive a sprocket off of an axle that's welded to the axle." Beat to death is a very kind way for you to describe the malefactor's work.

What do you mean by "attach to the axle"? I know you can't mean you'd attach the driven pulley to the axle and run the thing as a pure belt drive.

I mean with a chain. So the chain clears the frame