Spark plug load test

[oldyam80sg]

I wanted to do testing on my bike to see what the plugs looked like after running it for a while.I didn't have a stretch of road by me where i could do the test without drawing attention to myself from the local Police.So i did a slight modification to the load test described in another thread.I have a stretch of hill by my apartment that is approximately 1.5 miles long.I looked at the new plugs( less than 70 miles) and they had a very,very slight brown color to them.I started on this hill and was going around 35 mph.I had a car in front of me so i distanced myself so that i wouldn't be tailgating and the car was going around 40mph.I marked a spot on the throttle using masking tape and would shift into another gear and applied throttle only when the car picked up speed.The driver maintained his slow speed up the hill.In doing the testing that way i must have put the bike under load and when i got to my Moms house the plugs changed from very,very slight colored brown to a noticeable brown even color on every plug.

[TopCatGr58]

Hey Yam,

Depending on what RPM you were "loading" the bike going up that slight hill, you might have only been testing your pilot circuits, remember they are responsible for a considerable amount of throttle response up to 3.5K rpm before you start getting into the mains.

The idea with the throttle chop is to be USING The mains for some time and then SHUTTING it down instead of slowing down with throttle closed or low so that the color you find would NOT be altered by the Pilot circuit.

SO...you should go back to that hill, put it in a gear that will allow you to maintain a legal speed, but have the rpms above 3.5 k, and THEN KILL the engine at the top of the hill and pull the plugs and look at them.