Re: Handlebar choke kit /cooling/tuning aid/engine sa
Posted: Sat Jan 26, 2013 1:14 am
below is part of a pm i sent also that may be of use to you wack and others
as rpm increases you get a greater draw on the atomiser so
a 100 mjet at 7000
behaves like a 102 at 8k
and 104 at 9k
so adding additional circuits like power jets allows finer tuning that 100 main can be an 80 main with a 20 power jet giving a cleaner transition but still delivering 100
each time you increase one circuit it overlaps the next so a bigger main may need 1 clip leaner needle or vice versa
u can have full throttle delivery at 3k so delivering off the main jet occurs with the pilot and needle together so u can see how these overlaps interact ,i see it on the lambda readings everytime i dyno so is quite a familiar site
power does come from improved cooling effect its not more ,its a case of returning the power you just lost thru heat
the choke jet runs in conjunction with an air gallery so is in effect a minature carburettor,i ran dyno tests with a 60 choke removed and replaced with in the end a 25 jet and with a carb size restriction in our racing class of 19mm the 3mm bore choke gallery with the 25 jet effectively made it a 22mm carb but legal in class rules it outperformed the larger 21mm carb that some other teams cheated with so your carb with choke on at full chat might have a good gas speed thru the choke gallery and might not enrichen as much as people would think
as rpm increases you get a greater draw on the atomiser so
a 100 mjet at 7000
behaves like a 102 at 8k
and 104 at 9k
so adding additional circuits like power jets allows finer tuning that 100 main can be an 80 main with a 20 power jet giving a cleaner transition but still delivering 100
each time you increase one circuit it overlaps the next so a bigger main may need 1 clip leaner needle or vice versa
u can have full throttle delivery at 3k so delivering off the main jet occurs with the pilot and needle together so u can see how these overlaps interact ,i see it on the lambda readings everytime i dyno so is quite a familiar site
power does come from improved cooling effect its not more ,its a case of returning the power you just lost thru heat
the choke jet runs in conjunction with an air gallery so is in effect a minature carburettor,i ran dyno tests with a 60 choke removed and replaced with in the end a 25 jet and with a carb size restriction in our racing class of 19mm the 3mm bore choke gallery with the 25 jet effectively made it a 22mm carb but legal in class rules it outperformed the larger 21mm carb that some other teams cheated with so your carb with choke on at full chat might have a good gas speed thru the choke gallery and might not enrichen as much as people would think