Max_Morley
Serious Thumper
Offline
LT650 Luxury Touring & sidecar rig
Posts: 1490
Moses Lake. WA
Gender:
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On topic, I'd vote for an air leak at the head to head pipe or head pipe to muffler as this allows air (with 20.8 % oxygen usually) in the system and burn rapidly (very rapidly) any fuel left there from the closed throttle or shut off ignition. On altitude re-jet ? I've run mine from sea level to over a 9000 ft pass and it is set for 1200 ft which is the altitude where we live. It ran a little lean in Seattle area and I'm sure rich over the pass, but just kept on thumpin' in the snow in July. Years ago when I went to Auto Tech school in Klamath Falls OR, we used the 5000 ft altitude there as the cut point to rejet, we did many cars in the Tune-Up class using a chassis dyno to verify we didn't go too lean, this was before the days of Emission controls except for a PCV valve. Modern stuff, cars truck and now bikes with Fuel injection and O2 sensors check the barometric pressure on start up and at specified RPM, throttle setting, & load, check it again to use a different look up table in the computer to correct the A/F ratio on the fly. The O2 sensor(s) fine tune it from there like the scales of justice, out of balance lean add a little more injector on time, a little rich cut them back by a couple ms (milla-seconds) always varying so little you cannot feel it in the operation of the rig, but observable with a DVOM on the O2 sensor, GMM (graphing Multimeter), or scanner. Max
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