91 K75 no turn over/ "putting"
I have a 91' k75 with ~19k miles. I am the third owner to this bike; previous owner had no concept or care for maintenance. Rode for about 2 years without any noteworthy issues. Bike been out of commission since summer '08. Before posting, I went through all the posts in the forum in hopes of finding a solution. Alas, no dice. There was a former post about a issue that is no longer occurring but the bike is still not running right.
First issue: started bike, "cannon-blast" single backfire, then constant thick blue/white smoke from exhaust; bike would idle and did not lose power; good compression on all cylinders upon testing
Resolution: new plugs, cleaned injectors, cleaned fuel rail, replaced O-ring seals on injectors, replaced outer valve cover gasket (slight leak); smoke went away, but idle remained rough; believed fuel had leaked due to deposits in injectors which pooled then ignited causing the huge backfire
Current Issue: Bike will not remain running or idle properly under normal conditions; only way to get bike to idle is to manipulate vane/flap in airflow meter to middle of range and only then with choke or throttle open to some degree; more throttle = die, less throttle = die
What it does: starter whirs, sputtering trying to turn over, occasional larger sputter, no turn over, just revving
With assistance at meter: starter whirs, hard start to idle once vane is in an agreeable position, rough idle which ends when vane is released or pushed to max or too little/much throttle
Fuel filter replaced (was bad)
Fuel treated with LucasOil fuel treatment
Fuel injectors cleaned (some deposits but none have reappeared)
Fuel rail cleaned
Fuel tank inspected (sparkling)
Compression Test (all cylinders good)
New injector O-rings
Battery ground sanded/cleaned
TPS disconnected (no change)
Airflow meter disconnected (will idle very rough, but does idle)
Airflow meter opened and wheel adjusted for testing (worse or no change)
Two earwigs removed from inside FICU
Bunch of listening, figuring, unhooking, etc
Bad airflow meter
Bad soul (ICU/ECU/*CU)
Critical Note: Manipulating the airflow meter has the same effect whether installed in the airbox or free wheeling outside the box.
I'm thinking either airflow meter ($800 new - $50>$200 used) or injectors ($130 new each - $75>$100 refurb Ford injectors). At the price of the parts, I would prefer not to be tossing them at the bike for diagnostics. Raked my brain and good auto mechanic's brain for any light towards the root cause. I can't blame any of the suspects as too many variables are at play.
Assistance would be most appreciated. I'd post a YouTube video for diagnosing sounds if it will help.
Last edited by Vey; Jul 6th, 2009 at 10:43 pm.
Reason: critical info