DrunkenDwarf wrote on 07/09/09 at 18:45:33:In the morning (about 60 degrees Fahrenheit) I started with the choke out one notch. It idled pretty smoothly, with only the occasional stutter. After it warmed up and I pushed the choke in, it still idled fine.
This afternoon (about 75 degrees Fahrenheit) I started with the choke out one notch. It idled horribly rough, stumbling all over the place. After it warmed up and I pushed the choke in, it idled fine.
I'm sure that means something, but I have no idea what.
Working fine when 60 degrees, but misbehaving under the same conditions at 75 degrees - as long as the conditions like humidity and air filter and flow, and ambient air pressure and composition etc etc are the same - and believe me its only 15 degrees we are taking about so the rest has to be identical between the first and second trials - means it is rich. Its a shade rich. However I will not do anythign too drastic. You jet the bike to run on the coldest day of the year in your location. Yes painful time to be lying under the bike, or handling gasoline or carb cleaner ... brrrrr ... but jet it to run right on the coldest day of the year, and see if it does not misbehave too much when it is warm. Anyway, you can turn the air screw in ~1/8 tirn. It may cover your situation with room to spare.
DrunkenDwarf wrote on 07/09/09 at 18:45:33:With Dyna muffler...
Original jetting: 55 (1 turn out)/stock spacer/155
mpg: 52-55
New jetting: 55 (1 turn out)/no spacer/152.5
mpg: 40-43
Well, it fixed the lean mid throttle issue. Perhaps too well.
I'm definite putting some spacer back in (1/4-1/2 of stock). I'm not sure if I should go down a size on the pilot jet. Suggestions?
-D. Dwarf
I'd run the jetting that does better on gas mileage as long as you dont lean surge @ part throttle on the coldest day of the year.
So you run it for now, but in winter you need to test run it and check for lean surging between 1/4 and 3/4 throttle. A lack of a tachometer does not affect your ability to jet it right, In fact it helps you jet it via throttle position which is what determines what jet you are using, and not confuse people by saying 3500 rpm ... so is that 3500 rpm revving in your driveway @ neutral, or in 6th gear doing 40 ...
Cool.
Srinath.