Al this bathroom scale deal.... do you need to have stock style or lowest possible rpm lockup clutch on there to try this... I feel if I put a random bully on set to say 4500 and I didn’t need 4500 for that particular motor it would have a direct reflection on the scale reading.. please correct me if I’m wrong. I’ve been wrong before trust me! I’m willing to try this justvnot sure of your testing procedure.
The idea for the scale is that the scale will read its' highest reading when the kart acceleration is the greatest. It allows you to experiment with different clutch settings to determine which provides best acceleration.
If you understand how to do the test, do it. Regardless of what the RPM is at stall, write down the RPM and the reading on the scale. Adjust the clutch to hold the engine (stall) at a different RPM (up or down), take another reading, writing them down. Keep doing this till you find the stall RPM that produces the highest reading on the scale. The highest reading will tell you at what RPM (stall) the engine is producing the most torque at the axle. If you can, monitor the air density. Higher air density will produce higher readings on the scale. It's no different, actually, from testing your engine on a water/hydraulic break dyno. Any kind of dyno, acceleration or break, will tell you at what RPM your engine produces the highest torque reading. I 1st learned how to do this from a guy named Larry Moral. He built a hang glider called the Easy Riser. He did this exact same test to find the maximum thrust of a powered unit he had just developed. This was back in the early 80s.
The scale will read applied pressure.
If you use a clutch set too high you would not necessarily know , unless you made an adjustment and the pressure went up or down .
You should have a dyno readout or some idea where max torque was produced .realistically and 4500 stall on a stock class engine is not the best option for engagment .
Now , have I tried it no . Should I have tried it probably .
This is similar to how a kt100 clutch is set . You pretty much know where peak torque is so hold the brake and mash the gas ; set clutch accordingly .
If you have not changed it yet . Get you a batroom Scale. ( the spring style ) .
Test the 1850 spring then switch it too the new 2550 spring .
If it shows an improved pressue , you made a positive change .