hard start after servicing & back fires

[Bigtater]

Hi All,

1990 BMW k75s

Over the past week, I have been going through my somewhat new to me K-bike. I changed all fluids, spark plugs, air filter, cracked pcv hose, greased the final drive splines, changed the front fork oil, repaired my odometer gears, and replaced the steer bearings.

Once I put the the tank back on I attempted to start the bike since the first time I put it on the work stand. It would crank well, but not fire unless throttle was applied. At first, I thought this was because the fuel pump was still priming. Anyways, after a bit of cranking, I started to smell fuel. I gave it some throttle and I got a few pops from the exhaust. At this point, I pulled the plugs and they were wet from fuel. I then checked spark on two cylinders and got a strong blue spark. I proceeded to pull all three plugs and use a lighter to burn the excess fuel from the electrode.

I then reinstalled the plugs and verified the firing order was correct. After that, I started the bike with 1/4 throttle. It would run decently well, smelled a bit rich, and would occasionally backfire or pop from the exhuast. It will not idle. After repeating this process a bit I attempted to go back over everything checking for loose electrical connectors etc. The repairs made, don't seem to have any direct influence on the issue.

The only things I think that might be impacting the issue is that I replaced the cracked PCV hose, and replaced a K&N filter the previous owner installed with a factory paper element from beemer boneyard.

Anyone have any ideas? All help is appreciated.

[The Mighty Gryphon]

Are you sure the plug wires aren't crossed for cylinders 2 and 3?  The wire for #3 is longer than the one for #2.  I know the first time I changed my plugs I got them backwards and the engine did exactly what yours is doing.

The factory wires will have the cylinder number printed on them.