Good day to jet

I think we are around 700 feet in altitude. I never really understood humidity/dew point/pressure, but i would gather there would be less air w/ more humidity. With this crazy weather, it does help going from one extreme to the next. Much like removing the air filter and then putting it back on or using the choke to find a problem.

I've become decent at jetting by the seat of the pants and spark plug chops. Never jet for the perfect jet w/ an aircooled. A bit fat is always good especially to help cool a hotter aircooled motor.

It just takes me longer, but part of the satisfaction is figuring a good baseline on your own.

Since i've richened up the midrange, i decided to go to the 280 main, since the plug chop looked pretty decent. 280 is definitely ballpark (im my experience w/ stock motor, jetting goes up 1-1/2 to 2 main jet sizes when you go from oil injection to premix only in this case from 260 to 280), so i should get a more accurate indication this time of which carb circuit has a problem or not and where it is in the throttle range (if carb related). I want to wait for a better day and then try again ...mainly focusing on the midrange and seeing if that is better and if i got rid of the 1/2 throttle flatness, then a WFO and see what's up there. The racers ran even a richer P5 needle jet, which i have, but i would think that won't be the case, since i have about 23 less HP!!!

 

I think i will wait for better weather...the changes are a pain in the ass. The good news? Went from a #45 pilot to a #50 pilot and from an unbiased outside opinion (GF said it sounded better...ok will roll w/ that) and watching the throttle, i had better results. Same airscrew settings!! W/ the 50 pilot i had to use less throttle on takeoff. Watching it a 50~60 I only had to turn the throttle just past zero to maintain speed. W/ the 45 it was more closer to between 1/8th~1/4. Also cold from a stop taking off, just 3k rpm to move. The 45 required about 4k rpm to go froma stop. Left the 300 main jet in.

And my wheelie check...a firm tug in 2nd will bring the front up, not high, but that's always a good sign, this after a full hot engine (up to temp).

When i get more consistent weather, I will continue. Or at least a less cloudy day. Weird changes in temperature lately...chasing tail and all. Had a leaky right side exhaust, so new gaskets there and hi-temp copper RTV. Hopefully that fixed it.

 

When i looked it up it said 700 ft. years ago. Some map, maybe...i don't know.

No matter, jet seat of the pants anyway.