Anything Goes - Rusty Redneck's Polamaha Go-kart

[RustyRedneck]

Hey guys, here's my entry for the build-off this year. Not a mini-bike by any means but I think it fits in the anything goes class. I'm realizing a dream a friend of mine used to have and eventually sold to me. He and his brother were going to build a go-kart using the front end, rear end from a Polaris 4 wheeler, and a 400 cc Yamaha motorcycle engine and transmission. They got started on it but lost interest and ended up cutting the frame apart and throwing it in the junk pile. I just happened to be walking around his place one day and saw the tires and asked what the deal was with them. He told me about the go-kart and after finding out they'd put the engine inside the shed, I struck a deal with him and if I remember right I got the whole works for $80. Including the wiring harness and lights from the bike as well as the speedo and tach assembly, front wheel and gas tank. I don't think I'll be sing the front wheel but I think I can use everything else from the bike to make the go-kart run and drive. I hope. Anyway, should be a fun unit when done and hopefully entering the build-off will give me the motivation I need to get it done. Already bought a new seat from Jegs and a pickup load of 14 guage pipe scrap from the local steel store. I think I'm at about $150 so far and I think I have all the big stuff. Just gotta put it all together.

 

[chipper]

Sweet , otta be bad ass !

 

[mrpat]

Very sweet idea indeed! Good luck with your build.

 

[cheezy1]

Thanks for participating... :thumbsup:

 

[danford1]

I almost bought a 4 wheeler chassis to do something like that. I never did buy it though...Good luck with your build. I look forward to watching your build.
Danford1

 

[OND]

Man that baby ought to romppppppp !!! :thumbsup: I'm subscribed and Good Luck .

 

[t555trailblazer]

Cool project!

 

[RustyRedneck]

Ok. I brought the engine today and started trying to figure out how to mount it close to the rear axle to save space.
I think this whole thing is going to be tight at 8 feet long nose to tail. But if I can make it shorter and still drive it, I will. Anyway, I'm running into problems with the rear strut tower and swing arm. I want to keep the suspension but I don't know what I can get away with as far as modifying the geometry. The strut tower is too far ahead at this point to make the engine sit as close to the wheels as I want. If I was to cut the strut tower and stand the strut straight up, will it make my suspension stiffer or not work correctly? I also considered spinning the axle around and putting the shock tower and swing arm in backwards. That'd move my suspension back but I'm not sure if it would work right. The guy I got this whole thing from said that he and his brother were going to mount the engine above the rear axle but I have no idea how that would've worked. Anyway, here's pictures of the the mock-up with the rear axle forward

and backward.

Thoughts on the suspension?
I figure I'll need a jack shaft from the transmission to the rear end to at least adapt the sprockets. It'd also give me the ability to adjust my rear gear ratio easier.

 

[RustyRedneck]

I moved the shock mount on the rear end, rearward today at break. This should free up a little more room for the engine. I'm still hoping I can make this work with the pivot, forward of the swing arm. I don't think it'd work very well towards the rear. The more I look at it, the more modification I think it'll need to make it work. The way this swing arm was designed, the chain ran around it from before the pivot. If I run 2 jack shafts and 3 chains I might be able to suck the engine right up in front of the shock tower but I'm not sure if I want to have that many chains on this unit. Lot's to loose sleep over. I'm hoping to build the frame from the rear suspension to the motor mounts and then from the front suspension to the motor mounts coming together about at the seat. Anyway, it'll be interesting. Suggestions welcome on the suspension, I've never done anything like this before so it's all pretty new at this point.

 

[RustyRedneck]

Did some more work on the frame today. I finished welding in the upper shock mount and added pieces of pipe to front of the old 4 wheeler frame. I think I'm going to weld in taller lower shock mount ears to give it more clearance. I also think I'm going to mount a jack shaft on the swing arm to adapt the engine (sprocket on the left side) to the rear end (sprocket on the right hand side). This will also act as my gearing adjustment. I figure a 1 inch keyed shaft should be able to handle the torque from the engine. Then I just need to grab some chain, weld-on hubs, and sprockets to adapt from one size of chain to the other. I think that should work. Right? Anyway, I'll keep you posted.

 

[RustyRedneck]

I've been working on the motor mounts for the last couple days on break and I think I've got the rear ones about squared away but I think I can move the engine back a couple more inches. So to make sure, I'll build my front motor mounts and not weld them in just yet. Hopefully I can get a little more room out of it if this thing is going to fit in a long bed pickup box or a 4 by 8 foot trailer. Stay tuned

 

[RustyRedneck]

Got the front motor mounts done and I got the engine moved back about an inch and half. Welded in the motor mounts and now it's solid.
I haven't updated in a while s here come a few more pictures in sequence of my progress thus far.

 

[RustyRedneck]

Here, I have the seat setting on the frame just loosely to give me an idea of how much room I'll have when driving this machine.

 

[RustyRedneck]

Here it's mocked up with the front suspension in place. Not a lot of room between the seat and the front shock tower. I think this is when I decided to cut out the bars connecting the shock tower to the lower part of the frame. The reason for that is to stick my feet between the shocks under the chock tower and have the controls are far forward as possible. That way I might actually be able to drive the thing comfortably.

 

[Fantic Freddy]

Rusty, you should get points just for imagination. That thing will be scary with that Yamaha behind the seat. Make sure your life insurance policy is up to date. :thumbsup:

 

[RustyRedneck]

I stayed late last night and got the lower frame mostly done. I made it a bit shorter than I had planned. Trying to get it done quickly I cut the front frame rails that I had already welded to the front suspension too short. I did sit in it and I can fit. It's a little tight but once I add 7 more inches to the frame, it should be fine. I also cut and widened the front suspension 2 inches to make more room for my feet/lower legs to fit between the shocks. I think my next step is to mount the front shock tower so I can move it around without having to wrestle the front end around so much. It has to mobile from this point on because I'm working on it at work during break and after hours and with the lower frame structure present, I have to store it outside. Takes up too much space otherwise. The shop is cramped as it is. Hopefully I can get the front suspension figure out today. Stay tuned.

 

[RustyRedneck]

Rusty, you should get points just for imagination. That thing will be scary with that Yamaha behind the seat. Make sure your life insurance policy is up to date. :thumbsup:

Thanks Freddy! I plan on scaring myself with it. But, I also plan on being relatively safe. As far ahead of the rear axle everything is going to be, it should be really tail happy.

 

[RustyRedneck]

Sorry I haven't make an updates lately on the cart. I need to get back to work on it. My boss asked me to get out of the shop and it's better at home anyway. I can set it on blocks and leave it where I can work on it without moving it constantly. At the moment, it's sitting in the trailer with a couple inches of snow on it. Hopefully I don't loose interest in it.

 

[jeep2003]

Maybe you can get rid of the shock tower brace completely and just make some hoops on the sides up to the front bumper to hold them?

 

[RustyRedneck]

Maybe you can get rid of the shock tower brace completely and just make some hoops on the sides up to the front bumper to hold them?

That's kind of what the plan is at this point. I removed the old shock tower and will be mounting the shocks directly to the frame side bars. Lots of pipe notching to do to get this thing closer. It'll have to rows or horizontal bars on each side. Kind of like a dune buggy or production off-road go-kart but better. Hopefully as it warms up in this area I will be working on it more. Trying to make room in the shop for it today. Hopefully I can get that accomplished.