ST2-NG Pre-build "Think Tank"

[Master Hack]

I made everything. There is about a 12 inch center section with the brake and sprocket. The hubs and flanges were made outta junk, scrap and whatever l could scrounge.
Its all unconventional crap. It works and is in keeping with my MO, never buy what l can make! This is just a buggy for the grandkids to have fun with, probably not anywhere near the class yer working on. They do manage to thrash it around purdy good. Nothing has broken yet. Pics on request.

 

[Kartorbust]

Dennis Kirk finally had the gasket set back in stock. Order it up last night, got confirmation email it shipped this afternoon. Hope to have it here by Friday. Though should be here sooner since DK is based out of Minnesota.

After that, need to order up spark plug boots and figure out how to install those on the new ignition box. Anyone know how to cut the tires to install spark plug boots?

 

[Denny]

I’m pretty sure you don’t cut the tires to install spark plug boots. Please don’t cut the tires.

 

[Kartorbust]

I’m pretty sure you don’t cut the tires to install spark plug boots. Please don’t cut the tires.

Spellcheck got me and was half asleep. Thought I typed wires not tires.

 

[Master Hack]

Quietly waiting & watching for the tire/spark plug trick

 

[Kartorbust]

But in all seriousness, anyone have any tips on how to install the spark plug boots to the CDI wires?

 

[Whitetrashrocker]

Cut the wire to length.
Slide boot over wire.
Strip wire.
Connect wire to plug clip.
Slide boot back over clip.

 

[Kartorbust]

So basically about like doing normal wiring jobs. Yeah I still feel like I'm going to royally screw this up.

 

[Whitetrashrocker]

And here's how you cut a tire.

 

[Kartorbust]

Gasket set arrived today and...think I got boned. Website said it fits, but the packaging says it's for the 86-88 Panther and not the 77-79 Panther. I'll have to dig into it to see when Arctic Cat stopped using the Suzuki Spirit engines such as this one. If this set does not work, I'm kind of out of options, unless I can either figure out custom gaskets and seals.

If this does not work out, I am really thinking about just getting one of those Chinese Zongshen SOHC 250cc engines and redoing this whole project and take inspiration from another project on a forum that sadly no longer exists.

 

[Kartorbust]

Still no progress. Hours have been lacking at work, so I've been kind of looking for a new job. There's a couple fabrication shops much closer to home that I might apply to. They do ag repair as well as custom fabrication, so I might be able to use that to my advantage on this project.

Also got word from my dad and uncle that there is a place up by them that deals with salvaged snowmobile and ATVs, so I might abandon this snowmobile engine and try to get a newer one for a cheaper price that hopefully runs and has electric start. Still prefer it to be a 2 stroke since that's a lot easier to rebuild vs a lot of the 4 strokes.

 

[Kartorbust]

Almost tempted to modify this to be a knock off clone of the Chenowth Mini Mag. Engine I have is smaller in displacement (500 vs 570)

 

[Kartorbust]

Kind of have an idea going on how to make this all work. Other than getting a custom spool made to adapt VW Type 2 cv axles to it, plan is:

Type 2 CV axles with Type 1 stubs, Type 1 rear disc brake conversion minus parking brake setup. Get 15"x9" with the old 5x205 bolt pattern wheels for the back for Mickey Thompson 31x10.5x15. I have front wheels already from the buggy I got back in 2020, just need new rubber which will be the Mickey Thompson Mini Mag tires which, very old school E78-15 which today would be the equivalent of a 205/75/15.

Front suspension, I'm still working that out. Might have found a lead on A-arm style spindles, so those might work. Will be doing the Type 1 disc brake conversion for the front as well. Might be overkill to have disc on all four corners, however, rather have too much braking than not enough and end up wrapped around a tree at mach speed.

Gearing, I'm trying to figure out. Still deciding between 9:1 and 12:1. Might go to the latter because of the weight of those 31" MTs. With a 102c and 90D, top speed might be 55mph with the engine turning at 6000 RPM.

 

[Kartorbust]

1" and 1 1/4" are common axle diameters for us. How well would a stepped axle hold up? Just for schiz and giggles, looking at Spicer 1310 yokes that have a 1 1/8" bore with a 1/4" keyway. Odd size and unless I found bearings and sprocket hubs, my thought is, get chromoly round bar 1 1/4" diameter, have the width I'd need at 1 1/4" for the sprocket hub and th have the ends machined down to 1 1/8" to fit the yokes, then have it cut for the keyways.

 

[Kartorbust]

Trying to figure out the front brakes. Thinking on settling on using a 4on4 bolt pattern front and rear, using 12x7 golf cart wheels. Front brakes, looking at maybe doing golf cart disk brakes. You can find a complete front kit for like $700, including spindles with the caliper mounts. But I think that would still require having the hubs. Would have to swap out the master cylinder to help it run rear brakes. Still racking my head for the rear, might just do a single rear brake, like how the plans originally call for.

This would be the front kit I might go after.

Jake's Non-Lifted E-Z-GO Disc Brake Kit (Fits ST Express Models)

This golf cart part is a Jake's Non-Lifted E-Z-GO Disc Brake Kit (Fits ST Express Models) and works with E-Z-GO vehicles.

www.cartpros.com

 

[Kartorbust]

Finally found some information, the Spicer 1000 yokes I've been searching for are being discontinued. At 540rpm they are rated for 13hp and at 1000rpm they're rated for 20hp. About 1/3rd what the engine puts out. Now I did finally find Spicer 1310 yokes in the proper size, the kicker? $59 each...and I'll need 8 of the, so just about $500, not including getting a chromoly axle cut to size and keyed. Every chromoly axle shaft made for go karts are all tube, not solid, and also lack threads.

Would have to also source different rear hubs, instead of doing 1" 4on4, would need a 1 1/4" 4on4 hub, which should be doable. Would be easier if I had a lathe and mill, but lack the funds for either, as well as the electrical capacity for what I have currently.

 

[Denny]

A 1310 is a big joint. Like car sized.

 

[Kartorbust]

A 1310 is a big joint. Like car sized.

It is what was recommended by the Mini Buggy guys for years. I haven't checked the smaller size stuff. But 1310 are common enough to find replacements for. Need to find yokes, off the shelf that will fit either 1" shafts with 1/4" keys, or 1 1/4" with 1/4" keys. Most everything is in that 1 1/8" or 1 1/4" but with a 5/16" key.

Trying to avoid super custom parts that have to be machined. One off parts get stupid expensive and I would have to draw everything up in Free CAD, something I haven't practiced using in years, and haven't used CAD since 2010 in high school. Really the only parts that need to be cut out are the rear spool bearing support, the wheel hub bearing ends for the rear A-Arms, and a few other small parts.

So long as it can use mostly off the shelf go kart parts, I'll be happy. I've been trying with the idea of using splined and keyed shafts. Keyed in the center spool to run the sprocket hub and splined between the joints to the wheels, finishing off with keyed to the wheel hubs. Convoluted I know, but, would not have to worry about several key ways getting wallard out over time. Granted, the ST2 plans, and it appears the ST3 and ST4, they call to use full length keys and not just small partial keys between the u-joints. So it would be like 11" and 12" worth of keys, with only a couple keys that are only a couple inches in length.

Obviously would run several keyed split collars to help hold the keys in place and not fully relying on the set screws in the yokes at that point.

 

[Kartorbust]

1210 could work, but yoke options are very limited.

 

[Kartorbust]

I am open to any suggestions on axles though. The initial plans call for the spool section to be 13" with 1" key shaft with 1/4" keys, however 1 1/4" 1/4" key would work as well. The axle shafts are supposed to be like 11 1/2" from end to end, not including the length added by the yokes.