dcook3333
Dean
Okay, so I started with my other winter project at: http://www.diygokarts.com/vb/showthread.php?t=6609
See that for my other buggy.
Basically, it happened this way... I bought that other buggy and I tell the story over there. Then the kids are too afraid to drive out of my sight. Even though they are permitted.
So, I decide to get a cheap offroad double and then give it a little power because they are all weak. So... I buy this for 500 stock. I'd rather have a different one to start, but someone like tractor supply must have sold a ton of them in the area at some time in the past - so they were all around.
The engine was the 6.5hp Subaru. I take it and put it on the smaller buggy. Then I get a 420cc gx390 clone for this one. I mate it up with a comet 40. What a shoe-horn job. I had to mount the gas tank to the frame - I like this set up. Originally, I just used a straight jackshaft with a 10 tooth to 60 tooth sprockets. And I used the recoil starter. So, we took our buggies to the ATV trails and put them through their paces. I was impressed that they held up tough, but there was a few things I knew that I needed to change about this one...
First, the brakes were too weak for going straight downhill with 2 people (there are big hills in PA). Second, the gear was too low for a fast speed but too high for tight uphills over the rocks. It still did it, but was hard on the belt - we could smell it. Third, ground clearance - got held up on the rocks in a couple places. 4th - no reverse - but everyone has got that problem, right. 5th - steering made me tired.
Later in the summer, I put a rack-n-pinion from BMI (yerf dog) on it. You can see the set-up in the pictures. excuse my lack of engineering, but it works very well. I also put some good shocks (not just springs) on all corners. These changes made a ton of difference. It drove like a car. Then came winter....
And I started projects on both. I did the other buggy first -see that article. Then I turned my sights on this one. I originally was going to do 2 brakes on the axle, but this got dropped later on for good reason (see below). At least I got the one existing brake straightened and working much better with a cable instead of a rod. I mounted a battery for the electric start on the frame. While I was at it, I put some headlights up top. Was going to call it quits, but then I think again about trying to put an ATV tranny in it. And that's when things get stupid...
So, I decide on a transmission from an old polaris. It has low, neutral, reverse, and high. I get it for $120 shipped. I have the input and output shafts turned down to 3/4 with keys on each for another $100. Add $25 for some oil seals and I've suddenly got $250 sunk in it. Start re-engineering the whole mounting from scratch. Weld here - drill there. The whole engine and tranny slides together for chain adjustment. The bar on the back of the swingarm is moved back 4 inches to make room for all this. I wanted high gear to be a little faster than when I started, and I wanted more ground clearance. So I used a 23 tooth drive to a 40 tooth on the axle. 2 inches more ground clearance instantly. My overall high gear goes from 6:1 to 5.72:1. There were skid bars underneath that had to be moved up as well - another inch and a half of ground clearance, yet it's all protected pretty well. The shifter is re-using the original brake rod that came stock with the kart (I replaced it with a parking brake cable from carquest). That with the ATV's original shift lever and some home-built linkages gets the shifting done. It has a shift-lock on it which is a must have for this. Since the whole linkage can move with the swingarm movement, it can't come out of gear! I get the engine started back up at this point, but then I realize that whenever it is running - the torque converter will start spinning whenever the tranny is in neutral or between gears... Not good for shifting. The atv that the tranny came from handled this by having the rear brake right on the transmission. So... that's what I do. I get the assembly for $30 on e-bay, spend a ton of time getting all the rusted parts freed up, and get it on there. So, now there are 2 brakes - each run by a cable - the one on the axle and the one on the tranny. the one on the tranny is much stronger than the other, but I'm keeping them both.
On the first test ride, the chain skipped when the throttle was smashed in high gear. I could tell there was a lot of flex in the axle since the sprocket is fairly far away from the bearing. So then I came up with a setup for the bar and bearings between the drive and axle sprockets. It has a tightener bolt too which is proving to be the best thing I did on this whole project. The downside is I have 10 nuts to loosen before adjusting the chain. Oh, well.
Since then the test rides have been outstanding. I've really tried to be tough on it - although I'm just tooling around my dead-end street. The snow is still too deep to get it out. C'mon Spring time!!! I think it will hold up - I tend to overbuild everything but we'll see. If you like the way this turned out - DON'T DO IT. If you do, either be a whole heck of a lot better at it, or give yourself an entire winter for just the tranny part. I spent so much time on that, I don't even want to think about it...
BTW, I'm thinking my top speed is up around 50mph, now. I need to have the Local Safety Officer follow me to find out for sure. Low gear is about 10:1, so it crawls so nicely. Reverse is nice - there's no limiter - so I can freak out anyone who climbs in the passenger seat. Nothing like doing 25 or 30 in reverse!
I probably got more sunk into this than most other go karts, but a ton less than an atv costs. And it's got the roll cage and seat belts which the LSO approves of. And you can't believe the looks I get when this thing shows up at the ATV trails. It's one of a kind. People smile at it and then it takes off uphill and the looks turn to more one of disbelief. There's only a couple more things that I want to get around to on this - one is bigger tires. I think that I got the gears set up good for going from 18 to 22 inch tires on the back (2 more inches of ground clearance). Kenda makes one which will fit the same rim. The front is taking some more thought. I have 4x4 hubs now, but being careful about the wheel/tire to mate up to them. I'm thinking that an 8 inch wheel with a 19 inch tire is what it's going to end up being. That plus some splash fenders like I put on the other buggy. But... I've spent so much time on this lately that I'm taking a break right now. Maybe in a few months after we've ridden them a few times..
See that for my other buggy.
Basically, it happened this way... I bought that other buggy and I tell the story over there. Then the kids are too afraid to drive out of my sight. Even though they are permitted.
So, I decide to get a cheap offroad double and then give it a little power because they are all weak. So... I buy this for 500 stock. I'd rather have a different one to start, but someone like tractor supply must have sold a ton of them in the area at some time in the past - so they were all around.
The engine was the 6.5hp Subaru. I take it and put it on the smaller buggy. Then I get a 420cc gx390 clone for this one. I mate it up with a comet 40. What a shoe-horn job. I had to mount the gas tank to the frame - I like this set up. Originally, I just used a straight jackshaft with a 10 tooth to 60 tooth sprockets. And I used the recoil starter. So, we took our buggies to the ATV trails and put them through their paces. I was impressed that they held up tough, but there was a few things I knew that I needed to change about this one...
First, the brakes were too weak for going straight downhill with 2 people (there are big hills in PA). Second, the gear was too low for a fast speed but too high for tight uphills over the rocks. It still did it, but was hard on the belt - we could smell it. Third, ground clearance - got held up on the rocks in a couple places. 4th - no reverse - but everyone has got that problem, right. 5th - steering made me tired.
Later in the summer, I put a rack-n-pinion from BMI (yerf dog) on it. You can see the set-up in the pictures. excuse my lack of engineering, but it works very well. I also put some good shocks (not just springs) on all corners. These changes made a ton of difference. It drove like a car. Then came winter....
And I started projects on both. I did the other buggy first -see that article. Then I turned my sights on this one. I originally was going to do 2 brakes on the axle, but this got dropped later on for good reason (see below). At least I got the one existing brake straightened and working much better with a cable instead of a rod. I mounted a battery for the electric start on the frame. While I was at it, I put some headlights up top. Was going to call it quits, but then I think again about trying to put an ATV tranny in it. And that's when things get stupid...
So, I decide on a transmission from an old polaris. It has low, neutral, reverse, and high. I get it for $120 shipped. I have the input and output shafts turned down to 3/4 with keys on each for another $100. Add $25 for some oil seals and I've suddenly got $250 sunk in it. Start re-engineering the whole mounting from scratch. Weld here - drill there. The whole engine and tranny slides together for chain adjustment. The bar on the back of the swingarm is moved back 4 inches to make room for all this. I wanted high gear to be a little faster than when I started, and I wanted more ground clearance. So I used a 23 tooth drive to a 40 tooth on the axle. 2 inches more ground clearance instantly. My overall high gear goes from 6:1 to 5.72:1. There were skid bars underneath that had to be moved up as well - another inch and a half of ground clearance, yet it's all protected pretty well. The shifter is re-using the original brake rod that came stock with the kart (I replaced it with a parking brake cable from carquest). That with the ATV's original shift lever and some home-built linkages gets the shifting done. It has a shift-lock on it which is a must have for this. Since the whole linkage can move with the swingarm movement, it can't come out of gear! I get the engine started back up at this point, but then I realize that whenever it is running - the torque converter will start spinning whenever the tranny is in neutral or between gears... Not good for shifting. The atv that the tranny came from handled this by having the rear brake right on the transmission. So... that's what I do. I get the assembly for $30 on e-bay, spend a ton of time getting all the rusted parts freed up, and get it on there. So, now there are 2 brakes - each run by a cable - the one on the axle and the one on the tranny. the one on the tranny is much stronger than the other, but I'm keeping them both.
On the first test ride, the chain skipped when the throttle was smashed in high gear. I could tell there was a lot of flex in the axle since the sprocket is fairly far away from the bearing. So then I came up with a setup for the bar and bearings between the drive and axle sprockets. It has a tightener bolt too which is proving to be the best thing I did on this whole project. The downside is I have 10 nuts to loosen before adjusting the chain. Oh, well.
Since then the test rides have been outstanding. I've really tried to be tough on it - although I'm just tooling around my dead-end street. The snow is still too deep to get it out. C'mon Spring time!!! I think it will hold up - I tend to overbuild everything but we'll see. If you like the way this turned out - DON'T DO IT. If you do, either be a whole heck of a lot better at it, or give yourself an entire winter for just the tranny part. I spent so much time on that, I don't even want to think about it...
BTW, I'm thinking my top speed is up around 50mph, now. I need to have the Local Safety Officer follow me to find out for sure. Low gear is about 10:1, so it crawls so nicely. Reverse is nice - there's no limiter - so I can freak out anyone who climbs in the passenger seat. Nothing like doing 25 or 30 in reverse!
I probably got more sunk into this than most other go karts, but a ton less than an atv costs. And it's got the roll cage and seat belts which the LSO approves of. And you can't believe the looks I get when this thing shows up at the ATV trails. It's one of a kind. People smile at it and then it takes off uphill and the looks turn to more one of disbelief. There's only a couple more things that I want to get around to on this - one is bigger tires. I think that I got the gears set up good for going from 18 to 22 inch tires on the back (2 more inches of ground clearance). Kenda makes one which will fit the same rim. The front is taking some more thought. I have 4x4 hubs now, but being careful about the wheel/tire to mate up to them. I'm thinking that an 8 inch wheel with a 19 inch tire is what it's going to end up being. That plus some splash fenders like I put on the other buggy. But... I've spent so much time on this lately that I'm taking a break right now. Maybe in a few months after we've ridden them a few times..
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