I recently built my new CL S14 kart, and have installed my seat from my previous kart, an S12 CL.
I remember fitting the seat asymmetrically (5mm further back in the engine side)
When I started karting I was taught this to compensate for the weight of the engine package.
My question is, does anyone know if the factory already compensate for the extra weight on the right side by making the seat “attachment points” (or stays, whatever you want to call it) asymmetrical?
On the seat positioning chart it states that both sides are meant to be the same measurement (in my case 63,5 cm)
I don’t run any lead ballast on the seat, so the effect of the asymmetrical seat shouldn’t make the kart un-drivable.
Though the thought of my seat sitting incorrectly still nags me.
The problem with just “adjusting the 5mm” is that I can’t drill another hole so close to the other holes, because that would just make the originally drilled hole even bigger.
Another thing I would like to know your opinion on, is that the factory states that the seat should stick 1cm under the bottom of the frame. It seems a little extreme, and I’ve always fitted my seats either flush, or just above the bottom of the frame. (Doesn’t matter that much, because there is no grip here in Denmark)
Any seat-fitting experts that would be willing to help me out?
I’m not an expert on birels, but in general, seat mounts are square and not offset from factory. As for drilling holes close to each other, what I do is fill in the old ones with fiberglass (you can buy one of those repair kits for cheap), let it cure for a day, then you can drill as close as you want
I think sprint style karts the seat mounting points are square or symmetrical. However, the rear seat stays are easily bent to change this offset or width as needed.
A small amount of change such as 5mm in my experience would make little or no difference in the scale weights and is certainly not going to compinsate for the weight of the motor.
As for how low the seat goes, 10mm below the chassis doesn’t sound right. In my version of Birel (compkart and ricciardo) I go 10mm above the bottom of the chassis.
You didn’t mention what engine package you’re running but for my LO206 with an inboard clutch, I had no choice but to mount the seat at a considerable angle as are the other 4 strokes I see at the track. From a driving perspective, you don’t even notice it. As far as the weight balance, I don’t believe it would affect it nearly as much as the position front to back in the chassis having your seat slightly off angle. Are you using a setup guide for your chassis to determine the ideal recommended seat positioning?
As far as height, I used two pieces of square tubing under the frame and set my seat on there so it ended up flush with the bottom of the rails. Going below that just makes the likelihood of scraping the bottom of the seat over curbs which I didn’t want to have happen. A difference in a few millimeters below the frame rails may make a difference for someone at a top national level I would imagine, but in my case there’s so many other handling factors involved that I know I wouldn’t be able to tell the difference. I blow enough entries, apexes and exits as it is to worry about a 5mm height difference below the chassis, lol.