r97
Measure twice cut once
Hey everyone,
It has been a long time since I've been over to the DIYGK forum, but I finally have a project worth sharing with everyone over here. As the title says, I'm still at it. Now down to business; ever since I rolled my reverse trike go kart I built a few years ago I have been tossing around the idea of adding a fourth wheel. A mere four years later I'm finally doing it!
As I said I have been thinking of doing this for a while, but I have been putting it off to avoid spending the money. Fortunately I was able to buy a new toy back in October with all the money I had saved, a 1997 Gasgas JTX270 trials motorcycle. You can see pictures of me having a blast on it below! Since I got my bike, I have wanted to go out riding with friends, but most of them don't have a toy to ride. It also does not help that every time I let a friend on my bike they lose control and crash into something
. Here is where the go kart comes in. I wanted a second vehicle that would be easy for any of my friends to use, as well as a little safer.
To get my go kart up and running again I had to make a few changes. First was adding a longer axle in the rear, and then four off road tires. I got a great deal on the 16X8-7 Trial Wolf tires from BMI karts, but they were so deformed from shipping that mounting them without a bead blaster proved to be too difficult. After spending a day and a half trying to mount them, resulting in not even one mounted tire I broke down and ordered some tubes. They arrived today and I got one tire mounted in ten minutes or so; I will do the rest tomorrow. In addition, I also changed the final drive ratio to accommodate for the larger tires.
Next on the list of changes to be made was to fix the horrendous steering. I chopped off the spindle brackets, and mitered the frame for 20° of KPI. This resulted in a roughly 1/4" scrub radius for each wheel. I then welded the spindle brackets back on, this time they were set back at a 10° angle to create positive caster. Once those were welded I cut apart my spindles. First I reattached the axles, but this time at about 118° to adjust for the KPI and to gain 2° of negative camber. Lastly I fabricated some new pitman arms from 1/4" flat bar, this time at 105° angles to incorporate Ackermann steering geometry.
Yesterday I assembled the rear of the go kart. Tomorrow, once the paint on the frame is dry, I will be able to assemble the rest of the kart and then maybe even going for a ride! I also considered making changes to the swing arm of the go kart to shorten the wheelbase and to move the axle bearings out further. Unfortunately, I realized it is more work than it is worth right now. Of course if I do somehow bend an axle I'll go through with that plan, but for now I'm leaving it as is.
If all goes well I should have pictures of the finished go kart for you all by tomorrow night. I'm also looking for pictures of the kart as it was in its original three wheel form to better show the full transformation. Fingers crossed I can report a successful test ride tomorrow!
As a side note for those interested, I have also included pictures of the drift trike that I built, and the (finally) rebuilt motorcycle engine for my mini buggy project. The buggy project isn't dead yet, but it has evolved into such a complex and expensive project that it will probably be at least a few years before it will even get close to being completed. Regardless, I'll keep everyone here updated on that project whenever I make any significant progress.
Thanks,
Rory
It has been a long time since I've been over to the DIYGK forum, but I finally have a project worth sharing with everyone over here. As the title says, I'm still at it. Now down to business; ever since I rolled my reverse trike go kart I built a few years ago I have been tossing around the idea of adding a fourth wheel. A mere four years later I'm finally doing it!
As I said I have been thinking of doing this for a while, but I have been putting it off to avoid spending the money. Fortunately I was able to buy a new toy back in October with all the money I had saved, a 1997 Gasgas JTX270 trials motorcycle. You can see pictures of me having a blast on it below! Since I got my bike, I have wanted to go out riding with friends, but most of them don't have a toy to ride. It also does not help that every time I let a friend on my bike they lose control and crash into something
. Here is where the go kart comes in. I wanted a second vehicle that would be easy for any of my friends to use, as well as a little safer. To get my go kart up and running again I had to make a few changes. First was adding a longer axle in the rear, and then four off road tires. I got a great deal on the 16X8-7 Trial Wolf tires from BMI karts, but they were so deformed from shipping that mounting them without a bead blaster proved to be too difficult. After spending a day and a half trying to mount them, resulting in not even one mounted tire I broke down and ordered some tubes. They arrived today and I got one tire mounted in ten minutes or so; I will do the rest tomorrow. In addition, I also changed the final drive ratio to accommodate for the larger tires.
Next on the list of changes to be made was to fix the horrendous steering. I chopped off the spindle brackets, and mitered the frame for 20° of KPI. This resulted in a roughly 1/4" scrub radius for each wheel. I then welded the spindle brackets back on, this time they were set back at a 10° angle to create positive caster. Once those were welded I cut apart my spindles. First I reattached the axles, but this time at about 118° to adjust for the KPI and to gain 2° of negative camber. Lastly I fabricated some new pitman arms from 1/4" flat bar, this time at 105° angles to incorporate Ackermann steering geometry.
Yesterday I assembled the rear of the go kart. Tomorrow, once the paint on the frame is dry, I will be able to assemble the rest of the kart and then maybe even going for a ride! I also considered making changes to the swing arm of the go kart to shorten the wheelbase and to move the axle bearings out further. Unfortunately, I realized it is more work than it is worth right now. Of course if I do somehow bend an axle I'll go through with that plan, but for now I'm leaving it as is.
If all goes well I should have pictures of the finished go kart for you all by tomorrow night. I'm also looking for pictures of the kart as it was in its original three wheel form to better show the full transformation. Fingers crossed I can report a successful test ride tomorrow!
As a side note for those interested, I have also included pictures of the drift trike that I built, and the (finally) rebuilt motorcycle engine for my mini buggy project. The buggy project isn't dead yet, but it has evolved into such a complex and expensive project that it will probably be at least a few years before it will even get close to being completed. Regardless, I'll keep everyone here updated on that project whenever I make any significant progress.
Thanks,
Rory
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. Needless to say I now slow down and turn in a little later when there is a tree on the inside of a corner.