Motorcycle Repair: GSXR 750 k2, fuel pump relay, coil tester

Question
Hi there from the uk.
Not sure if you can help me, i'm having a running problem wiht my fuel injected bike.
It seems to run fine over 2,000 revs but will stall or cut out below this, i have cleaned all the filters, injectors, changed the fuel and checked for any vacume leaks, by spraying easy start around the injection rack, nothing seems to cure the issue, do you think it may be a coil or injector problem?

Answer
It sounds like you have tried some of the usual methods of elimination. Some shops have a coil tester. you would have to remove it and take it in to be load tested. Most coils are a hard fail and do not have a partial break down. This may be an expensive fix. You could have a throttle body not spraying enough fuel at low rpm's. It could also be the throttle position switch on the main shaft through the bodies. Put in fresh plugs and go down 1 number for instance a BR8-ES is normal but a BR7-ES is hotter. Start the bike and rev it up a few times then pull the plugs and see if 1 or more of the plugs are really white or ash color as this may show you which cylinder is running lean and not getting the fuel. This will at least arm you with info on which cylider is having a problem. Here's another for instance. the fuel pump is on a timer wired through the oil sender. The idea is that the pump runs long enough to start up then when enough oil pressure is reached the fuel pump relay will stay on. If the bike is wrecked the pump wont stay on spraying fuel if the engine quits so it wont turn into a fire bomb. The fuel pump may only be able to stay on because the oil pressure is high enough at the higher rpm.