Finks Spiderbox Build

[Fink343]

Picked up a Spiderbox a few months ago and am doing a 420cc swap on it. My kids have Go Karts and I wanted one that I could ride around in with my youngest daughter so her and I are building this one for us. Sons is a Streaker 8 and my oldest daughter has the Yerf-dog 3002.

 

[Fink343]

Cut up the Swing arm. The 150cc engine that came with it was is bad shape and the 420cc was on sale. Plus its an excuse to play with my grinder and welder. Going to go with a heavier shock in the rear if anyone has suggestions on what a good shock for the rear is that will give me some extra lift would be awesome. I did a quick mockup of the engine yesterday and today i tor the front bulkhead apart to get ready for all the new BDX parts that I ordered. Getting the works. going with a 22X11-8 kenda pathfinder in the rear and a 19x7-8 in the front. Also getting the Steering send out for extra teeth cut into the rack from buggy depot.

 

[Fink343]

While its all apart I'm going to reinforce it with gussets and weld up the bulkhead anywhere I can add more metal to it. Been fun so far, Hope to end up with a final product that looks like this red Spiderbox when I'm finished.

 

[gman3850]

I recommend just rebuilding the whole swing arm. That way you can get a 1” axle and have the correct gearing.

 

[Fink343]

I recommend just rebuilding the whole swing arm. That way you can get a 1” axle and have the correct gearing.

That’s in the long term goal. For now I’m just going to get it running for light trail riding. Later I’ll get a 42” long 1” axle.

 

[Fink343]

I recommend just rebuilding the whole swing arm. That way you can get a 1” axle and have the correct gearing.

Do you have a reference for gearing and tire size?

 

[gman3850]

With 22”s on that size kart with the comet 40/40d I would at least recommend a 6:1 gearing. I would personally shoot for a 6.6. What size jackshaft are you running.

 

[Joe-405]

Sure is a lot of Spiderbox builds coming out of the wood works after I started mine ! I know of at least 3 within a few months now on this site.

I just went long travel style with full Yamaha atv front end on mine so if you need any pointers............

 

[Fink343]

With 22”s on that size kart with the comet 40/40d I would at least recommend a 6:1 gearing. I would personally shoot for a 6.6. What size jackshaft are you running.

3/4 inch jack shaft with a 10 tooth sprocket to the stock 150cc sprocket

---------- Post added at 11:07 PM ---------- Previous post was at 11:06 PM ----------

Sure is a lot of Spiderbox builds coming out of the wood works after I started mine ! I know of at least 3 within a few months now on this site.

I just went long travel style with full Yamaha atv front end on mine so if you need any pointers............

thats an awesome set up. I ended up going with this kit https://www.buggydepot.com/product/...for-yerf-dog-or-custom-builds-was-714-95.html

 

[gman3850]

3/4 inch jack shaft with a 10 tooth sprocket to the stock 150cc sprocket

stock sprocket on the spiderboxes should be i think a 33 or 37. So that means youll be running a 3.3/3.7 to one ratio. That is way to low and will destroy the belt.

 

[Fink343]

I can go larger on the jackshaft sprocket would that fix the ratio?

 

[Fink343]

This is what I would have with the current setup

 

[Joe-405]

Well I wanna see it when you get the stuff in. I had a bad run in with buggy depot so I opted for another route to finish my front end. I also did it due to the fact that BD is the only place you can get those parts if something breaks also. All my stuff is readily available just about anywhere now so it should be easier fixing something when it goes bad.

I’m also curious how that 420 will perform. I’m gonna run a 600cc or bigger sport bike engine in mine. It’s basically gonna be a Mini Sandrail when done. But I’m gonna drag race it on asphalt also.

 

[landuse]

This is what I would have with the current setup

That ratio is just not going to work. Sorry. You are going to have to at least get about 6:1. You will destroy any belts that you use, and the kart won't even move. Think of it as trying to take off from a dead stop in your car using 4th gear

 

[Fink343]

That ratio is just not going to work. Sorry. You are going to have to at least get about 6:1. You will destroy any belts that you use, and the kart won't even move. Think of it as trying to take off from a dead stop in your car using 4th gear

Which sprocket/s would you suggest changing to get better results? I'm open to any thing. This karts not going to be for any kind of competition Just using it to cruise around the yard with my daughter and Logging roads in maine.

 

[mckutzy]

Your going to need at least a 60t more on the rear...
And your tires aren't 7" OD(as per the screen cap shown).. more like 22" OD..

What size is the chain on the jackshaft sprocket?

 

[Fink343]

Your going to need at least a 60t more on the rear...
And your tires aren't 7" OD(as per the screen cap shown).. more like 22" OD..

What size is the chain on the jackshaft sprocket?

#50 chain. the OD on the driven is the torque converter not tire size
"Drive Wheel Circumference In Inches" is tire size and thats 22"

 

[TT540]

I too am in the Queue for a SpiderBox build. They are still around the $500 mark local to me. hoping to find a no-engine one for a little less.

Thanks for starting the thread and sharing.

 

[Fink343]

I picked this one up for $200, Can't Complain. Most of the running and going ones around here in New England go for 800-1200

 

[mckutzy]

As per this diagram you provided... these calculations are for the OD of the tire... not the TC
(it has no place in this calculation)

Equally speaking, the circumference(is the distance around wheel's tread for ex.) of a 7" outside diameter wheel, is 21.991148575128552....Like you have shown.... but...
A 22"OD has a circumference of 69.11503837897544.... big difference...
Measure the OD and get back to us... that part is important to figuring the proper ratio....

Edit: you most likely are going to have to change to a different size of chain, as the diameter of a larger tooth count sprocket in #50 chain will be quite large and greatly limit your ground clearance... much better choice would be a #35 or a #40/41.....

Edit 2: Your desired 6:1 ratio with #50 chain will yield about 12.5"OD for a 60t. A #35 chain will yield a 7.380"OD but most likely need about a 72t which is 8.814"OD still just about half and where youll need it...