mieczkow
Tom Mieczkowski
I have a 1987 K75S and ten years of mostly trouble free history. Over the years I have done all the routine maintenance myself. I have a well equipped shop as I also restore old Lotus Cars. I have run into a problem which has me stumped and after two days of working on it I am more or less where I started. Hoping someone can suggest some next steps to take.
I drove the K75 to my shop and shut it down. I was doing a little cosmetic clean-up on it. When I went to restart it it would not crank. Having been through this before I removed the tank, tapped the starter relay and it started up. That relay was replaced about five or six years ago. I decided to order one and replace it. I ordered one from Texas Industrial and it arrived. When I installed the new relay I had "runaway starter syndrome". The relay had clamped closed. I disconnected the battery to shut the bike down.
I had a pretty small Westco battery in the bike and it was about six years old. I decided that the battery might be contributing to the relay seize so I bought a full size aftermarket battery which fit the bike like a glove. Tried starting it and had the starter run away again. Shut it down and put in the old relay. Bike would crank but wouldn't start.
Started checking things. Fuel pump runs, tank is super clean, fuel is good. Put a fuel pressure gauge on it and have 38 psi after the fuel rail. Checked the fuel pressure regulator, found a break in the vacuum line and replaced the line with a new one.
Went to start the bike. It was a little balky but it did fire up and ran normally. No smoke, good throttle response, sounded just like normal. Shut it down. Went to restart it a little later, would not start. Continued to crank it but the starter would at times crank robustly and at times weakly. Finally stopped cranking.
Put a charger (trickle) and left it overnight. Next morning started up, but same as before. A little balky and then it caught and ran normally. Shut it down. Went to restart and it would crank but not start. Checked plugs, put in new ones and all the plugs are getting spark. Plugs are also fuel wet when I Inspected them.
If I jump the starter relay it cranks like the devil, much more robust than going through the relay. Sounds like the starter is very healthy (it was replaced about five years ago) and the battery seem to have plenty of power.mLights are bright, etc. charger indicates battery is good.
Went through the same scenario today. Checked everything again, fuel pressure, spark, plugs, etc. cranked it and it started. Shut it down and then back to square one, would not start but will crank. However cranking via the relay still seems weak/slow compared to jumping the relay and going directly to the starter motor. Can the drop-out relay be a problem here? I've tested the relays on the bench and they all activate when 12V is applied.
Boy after two days of this I've run out of ideas and starting to lose my sense of rational thinking about how to diagnose this. Can somebody slap me upside the head and point me in the right direction. I have a sense this is electrical, relay involved but I'm not at all sure what I should do next.
I drove the K75 to my shop and shut it down. I was doing a little cosmetic clean-up on it. When I went to restart it it would not crank. Having been through this before I removed the tank, tapped the starter relay and it started up. That relay was replaced about five or six years ago. I decided to order one and replace it. I ordered one from Texas Industrial and it arrived. When I installed the new relay I had "runaway starter syndrome". The relay had clamped closed. I disconnected the battery to shut the bike down.
I had a pretty small Westco battery in the bike and it was about six years old. I decided that the battery might be contributing to the relay seize so I bought a full size aftermarket battery which fit the bike like a glove. Tried starting it and had the starter run away again. Shut it down and put in the old relay. Bike would crank but wouldn't start.
Started checking things. Fuel pump runs, tank is super clean, fuel is good. Put a fuel pressure gauge on it and have 38 psi after the fuel rail. Checked the fuel pressure regulator, found a break in the vacuum line and replaced the line with a new one.
Went to start the bike. It was a little balky but it did fire up and ran normally. No smoke, good throttle response, sounded just like normal. Shut it down. Went to restart it a little later, would not start. Continued to crank it but the starter would at times crank robustly and at times weakly. Finally stopped cranking.
Put a charger (trickle) and left it overnight. Next morning started up, but same as before. A little balky and then it caught and ran normally. Shut it down. Went to restart and it would crank but not start. Checked plugs, put in new ones and all the plugs are getting spark. Plugs are also fuel wet when I Inspected them.
If I jump the starter relay it cranks like the devil, much more robust than going through the relay. Sounds like the starter is very healthy (it was replaced about five years ago) and the battery seem to have plenty of power.mLights are bright, etc. charger indicates battery is good.
Went through the same scenario today. Checked everything again, fuel pressure, spark, plugs, etc. cranked it and it started. Shut it down and then back to square one, would not start but will crank. However cranking via the relay still seems weak/slow compared to jumping the relay and going directly to the starter motor. Can the drop-out relay be a problem here? I've tested the relays on the bench and they all activate when 12V is applied.
Boy after two days of this I've run out of ideas and starting to lose my sense of rational thinking about how to diagnose this. Can somebody slap me upside the head and point me in the right direction. I have a sense this is electrical, relay involved but I'm not at all sure what I should do next.
