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TECHNICAL MOTOBRICK WRENCHING In Remembrance of Inge K. => The Motobrick Workshop => Topic started by: BENSPEN on August 07, 2017, 04:24:56 PM

Title: k100 runs for a while then dies and won't re start. fuel pressure? Please help
Post by: BENSPEN on August 07, 2017, 04:24:56 PM
Hey guys, as some of you may know i finished a k100 build a couple months ago and rode it to school, I left it at school for a week and documented it on here. After, when I was riding it home I did a little speed pull because I was trying to set the rings kinda just wring it out because we all know it will run better with some breaking in, it was the first time I had really given it any gas. It then died and left me stranded. It would fire for a second every time I hit the starter but then fall off, I pushed it almost a mile back to my shop. I let it sit there for 2 months because I was burnt out on the project. I then took it down to the block, cleaned the throttle bodies and injectors, but most importantly I checked all my spark plug wires and all plugs had spark and that makes sense because the bike does/did fire even for a second. I put it all back together and it ran rough but I rode it around my shop for a couple minutes and it seemed alright so I took it down the road with a lil speed pull (bit of boost lag but it felt great). And I get to the end of the street and it dies, same thing as last time and it won't idle just dies, throttle doesn't help. I have undone the fpr vacuum hoses tried to blow them out without prevail. I have no idea what the issue is, I unplugged the tps and it didn't help, I do not have any idea what the issue is.


Any suggestions are greatly appreciated.
Thank you all very much.
-Ben
Title: Re: k100 runs for a while then dies and won't re start. fuel pressure? Please help
Post by: BENSPEN on August 07, 2017, 04:28:54 PM
Photo of the finished aesthetic product minus the mirror. It's actually broken down with the issue when


* IMG_2342.jpg (76.72 kB . 743x576 - viewed 704 times)

I took this photo :falldown:
Title: Re: k100 runs for a while then dies and won't re start. fuel pressure? Please help
Post by: rbm on August 07, 2017, 07:19:14 PM
The turbo equipment does add a complication to your diagnosis that most others here on the forum do not have to contend with.  That may or may not be contributing to your problem.  How difficult is it to bypass the turbo so that you have a normally aspirated machine.  That way we can most probably help.
Title: Re: k100 runs for a while then dies and won't re start. fuel pressure? Please help
Post by: Laitch on August 07, 2017, 09:30:23 PM
Quote from: BENSPEN on August 07, 2017, 04:24:56 PM
Any suggestions are greatly appreciated.
Title: Re: k100 runs for a while then dies and won't re start. fuel pressure? Please help
Post by: The Mighty Gryphon on August 07, 2017, 10:20:38 PM
Quote from: Laitch on August 07, 2017, 09:30:23 PM
  • Is the battery ground connection on the transmission clean and tight on bare metal? Are the frame grounds clean and tight also?
  • Is the fuel pump under-tank connection clean and tight?
  • Are both the ignition control plug and the fuel injection control plug fitting tightly?
  • Have you verified that the coils are paired with the correct cylinders and verified the integrity of the coil connections to the ignition control module?
  • Do the spark plugs use terminal nuts for their lead connections or are they well-connected using only the top screw connection?
  • When the engine has stalled, have you pulled the spark plugs to determine if they are dry or wet?

First thing to check!
Title: Re: k100 runs for a while then dies and won't re start. fuel pressure? Please help
Post by: BENSPEN on August 07, 2017, 10:30:28 PM
Laitch, thank you very much for your contribution and I will look into it as soon as possible and get back to you.


I am pretty sure it is getting fuel after it stalls but I am not sure, after the first time I pulled the injectors in a haste and they were squirting but I didn't take the time to observe pressure or anything, but, I will check again.


Rbm, the only way to bypass the turbo system is to pull the intercooler which is really easy, but the turbo system adds a secondary fuel pressure regulator with a fuel pressure adjustment screw which adds a lot of complexity...


Thanks again guys I'll look into it and get back asap
Title: Re: k100 runs for a while then dies and won't re start. fuel pressure? Please help
Post by: Laitch on August 07, 2017, 10:36:17 PM
Quote from: The Mighty Gryphon on August 07, 2017, 10:20:38 PM
First thing to check!
Piffle! :giggles
Title: Re: k100 runs for a while then dies and won't re start. fuel pressure? Please help
Post by: Martin on August 07, 2017, 10:50:39 PM
Sounds like it is staving for fuel, could be pump or pump connection, fuel filter, fuel lines. After it stalls disconnect the fuel line at the rail and try pumping into a vessel. Pump should pump around 2.2 litres per min as tested on my OEM pump.
Regards Martin.