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View Full Version : Not a problem, A question re fuel maps



useless
02-18-2007, 10:01 PM
Just had a directlink look at my fuel maps. It seems to me the rear cylinder is set up leaner than the front.
Anyone know the whyfors and wherefors regarding fr and rear maps?
All opinions, experience, knowledge, appreciated
thanks

BuellPartsGuy
02-18-2007, 10:25 PM
It has some to do with the fact that the rear cylinder experiences more heat than the front cylinder.

useless
02-19-2007, 12:01 AM
Normally if you want to knock a few degrees of a cylinder you would fatten up the top end a bit.
The whole map is generally richer.
My initial thoughts were the directlink got the fr and rear mixed up.
I originally did this because I thought the bike was running a touch rich in the midrange when operating closed loop.
Considering the closed loop operation uses the rear cylinder as a reference, maybe its the fr cylinder that is rich rather than the rear being lean.
The only other thing is some oddball effect re cam timing?
I will use the rear map on the front and see what happens!
cheers

SylvanSlayer
06-18-2008, 02:43 AM
In any twin, one cylinder always runs hotter, this thier way of compensating

LeFox
06-18-2008, 07:48 AM
yea, the rear is always set leaner...have no clue why, though.

typeone
06-18-2008, 11:59 AM
its because of air temps and header design.. . "the front cyl is cooler. a colder air charge is denser, needs more fuel"

you can tune the rear cyl map (its got the 02), copy it to the front then add 2 points over the whole map. this is with ECMSpy, not sure if the value of '2' would be the same in the directlink world. but the front map needs to be richer.

if you can get another bung welded to the front pipe, you could tune both individually. this is optimal.