So I got all my parts for the race kart. I just need to put them on. I have a couple of spare parts so I am not going to install everything just yet, but these are the parts that I did install.
The first part that I wanted to change out was the rear sprocket. For the PRD spec class that I want to run I need to put a 77 tooth rear gear on the kart. The guy I purchased the kart from said it was legal in the configuration that it was in but I don’t want any issues. To change out this gear, you need to do a couple of things.
First you need to take off the tire on the side of the kart that the gear is on. This will allow you to slide the gear off after you unbolt it. There are 3 10mm bolts that are holding on my rear tires. Yours may be different but the wheel needs to be removed.
You will then need to loosen the motor mount bolts so that you can slide the motor back and take the chain off the sprocket. These bolts are located underneath the motor. The motor sits on a plastic mount and is held in place with two blocks that grip the frame rails. There is also a rubber stop that keeps the motor the proper distance from the rear sprocket to keep the chain tensioned properly. The bolts were giant Allen bolts. I believe that I used a 10 Allen key to loosen the bolts. They do not need to come out, you just need to loosen them enough so you can slide the motor back and take the chain off the sprocket.
This is the rubber stopper
Allen Bolts For PRD Motor Mount
Once the chain has been removed, you can unbolt the rear sprocket. My sprocket was held in place with 3 10mm bolts that I removed. Once removed, I was able to slide the gear over the rear hub of the wheel that I removed.
This is the Rear Sprocket that was on the kart.
The bolts holding the sprocket on were 10mm.
The new one just slid on the way the old one came off, just bolt the new one on and you’re good to go.
New Rear Kart Gear 77T
I also wanted to change out the drive gear that was on the motor. The one that was on there was an 11 tooth sprocket, the class that I want to run requires a 10 tooth sprocket. This was a little harder to change out; you need a 1 ½” socket to make this job even feasible. I did not have one and ended up at the auto parts store looking for a giant socket. You’ll see below why I needed it.
You will need to remove the plastic cover that is covering the 11 tooth drive sprocket. On my PRD Engine, there were 3 Allen bolts holding the cover in.
Then you can remove the bolt that holds everything in place. I stuck a flathead screwdriver in the starter gear to keep the shaft from turning and removed the bolt.
The next thing that you’ll need to do is remove the C-clip that holds the entire assembly in place. Again I used a screwdriver to pry it out.
This is the clip i mentioned.
Once that clip is removed, you can take the entire housing with the drive gear attached off the drive shaft. It will leave a dual bearing setup exposed.
This housing will slide right off.
The giant nut is on the other side of the drive sprocket assembly that you just removed. It is a 1 ½” nut, and I used a giant socket and channel locks to remove the drive gear. There is a little knob that keeps it in place that you will want to take care not to lose.
There is a tool for this, but i don’t have it!
Once it is removed, assembly is the exact opposite. Make sure that you use the little knob to keep the drive gear in place. Before re-assembly, I also used some grease to lubricate the bearings on the drive shaft. Not sure if it was necessary but it seemed like a good idea.
Once everything is bolted up, I needed to move the motor forward quite significantly to get the chain adjusted correctly. I also needed to re-route some of the water hoses as well as one of the seat supports that were now interfering with the motor.
The Chrome Bar connected to the seat needed to be re-routed
I needed to re-adjust the exhaust, i loosened the two bolts underneath it to move it around.
If you found any of this helpful, please let me know in the comments section below.