Wolfshoes
Member
With windy blistering hot 90 degrees F temperatures in the Chicago area, I have been comparing uphill performance of my single speed 66 china girl with its performance in similar conditions except being in cooler seasonal conditions. Wind seems to be a surprisingly big factor, almost a kiss of death, in uphill riding if the rear sprocket is optimized for flat high speed riding. In my case a 36 tooth rear sprocket with 26" rims. I suspected that in cool weather, the engine was not staying warm enough in the wind and this was affecting performance, especially uphill. My conclusion at this point is that drag from wind alone explained the performance drop and engine temperature is not a factor. I am using a Iridium NGK BPR7HIX plug, and the question was, would I be better off spring and fall to use a "hotter" spark plug. Using the plug recommended by the manufacturer done not really exist with the china girl since the plug sent with the motor is not suitable for the higher revving two cycle engine in my opinion. What I am going to watch for in the future is does riding for extended periods in the wind cause the engine to misfire. If it does the spark plug may be loading up and could perhaps benefit from a hotter spark plug.
Up till now, I really did not know what was meant by a hotter or cooler spark plug. I found a video on You Tube that provided a good explanation. It relates to the rate the plug tip was allowed to radiate heat into the head of the engine to maintain the minimum temperature needed to keep the plug from fouling. Two cycles are likely running cold in the wind more than 4 cycles, perhaps making plug temperature more of a issue. Experienced builders may roll their eyes at some of this video, but it provides a clear explanation needed in selecting and checking the performance of spark plugs. This could be helpful to riders in areas that get really cold in the winters; like below 40 degrees F.
Up till now, I really did not know what was meant by a hotter or cooler spark plug. I found a video on You Tube that provided a good explanation. It relates to the rate the plug tip was allowed to radiate heat into the head of the engine to maintain the minimum temperature needed to keep the plug from fouling. Two cycles are likely running cold in the wind more than 4 cycles, perhaps making plug temperature more of a issue. Experienced builders may roll their eyes at some of this video, but it provides a clear explanation needed in selecting and checking the performance of spark plugs. This could be helpful to riders in areas that get really cold in the winters; like below 40 degrees F.
