Almost unpredictable stalling/cut out

[Lenn0x84]

Hi all, I've got problems... 

So I've been chasing this gremlin for 2months now and really need motobrick help. I'll setup the scene and as you guys suggest tests I'll do them if I haven't and post everything in timeline to make it easier to trace for others. So... Bike was working fine, been riding it for a few months and 1 day noticed at about 3/4 of the way to work (45mins) while at the lights@idle, revs sorta dropped in spikes below 1000rpm in flutters, almost feeling like it might konk out. Rode of and kept revs sorta high and everything was fine. This happened randomly and became more frequent until 1 day it left me on the side of the road. I have had the injectors cleaned, hall replaced, new coils leads, re-crimped coil connecters, new fuel filter, new fuel hoses, balanced tbs. With this having been done, my baby will idle no problem, revs on the stand OK, ride her for anywhere between 5-15mins and she'll leave you on the sidestrip, sometimes start-up straightaway, sometimes not, fuel pump seems fine and is on when you hit the starter, checked the connecter. When I forced her to take me home, sounded like she was starving of fuel before cutting out, I haven't checked fuel pressure, I'm not sure what tool to use. Being in Australia the main stores super cheap, repco and bursons are either useless or too expensive for shit quality stuff and they're just salesmen rather than people with knowledge. If in any of your suggestions you can advise how to build or where to buy the tool I need to perform the test please let me know.

I'll stop it there, anything I've left out I will bring up when needed.
Thank you all for your help in advance and hopefully I'm on the road soon. I've got a cdi unit to swap over which I might do today, will let you know what happens. In my mind I'm leaning to either electrical or fuel.... We'll see what happens

Thanks again

[Scott_]

Something you didn't mention is the condition of your air filter, and/or checking the airflow meter.

[Lenn0x84]

Hi Scott

Air filter is new, was replaced at the start of the year, don't know how to test AFM but I did clean it with CO2 cleaner.

 :2thumbup:

[Fossil]

I think I have had that problem,,,try the propane around the injector tubes(rubber sleeves) trick. If the idle speed picks up you have cracked sleeves. It's not a hard job to replacerings them. Change o-ring at the bottom of each injector stub at this time also.

[Lenn0x84]

Hi Fossil,

Already tried that, no luck. No change in idle at all, sprayed all around intake and even near crankcase breather.

Keep em comin  :2thumbup:

[Jeff Sichoe]

Hey dude!

I had what sounds like this issue, pretty sure it was bad fuel in the end...

you mentioned checking 'the connector' was this the under tank connection to the fuel pump? Make sure that thing is real clean and tight!!

[Lenn0x84]

Cheers Jeff,

yet it was the undertank connector I was talking about, I'll give it another look and see if I can tighten it up.

cheers

[Grim]

What caught my eye is you saying it runs fine cold. 

This injection relies on engine temp to make its fuel decisions. Check your temp sensor. Also clean and reseat the plug for the ECM.

[wmax351]

Check the temp sensor, and the hall sensor. Both can act up when warm. Check the PCV hose on the intake plenum as well. The cold start enrichening can mask issues here.

[Lenn0x84]

Cheers guys,

I already replaced and tested the hall sensor, so thats ok. What I did notice is when I start it, the fuel pump is on while starter pressed but do sent stay on for a few seconds later. Just from the feel of it... I'm going to take a closer look at the fuel relay, and also I've got a spare cdi which I'll plug in... My train of thought is either cdi "overload" (shitting itself) and not keeping fuel relay on, or the relay itself going. Thats just a feel, but I also should test that water temp sensor. I've checked the air intake hose and don't see or feel any air leaks.

Thanks grim & wmax... We'll see how we go. Fingers crossed.

[Scott_]

the fuel pump is on while starter pressed

That's normal operation for the fuel systems, with the starter button pressed or with the hall sensors detecting engine rotation the engine controller energizes the fuel pump relay.

[Lenn0x84]

:euro :riding: woooooohooooooooo!!!

FIXED!!!  :clap: :clap:
So, thanks for your help guys.  :2thumbup: In the end it was the CDI and the plug, seems like the cdi needed a monstrous push to click in the female plug... But once in, the plug under the tank would also sometimes fail, and needed to fix the hall sensor connecter too... cleaned and tightened the inner joins... Done. Took her for a solid hour ride, hard and well behaved and she didn't give me any issues.

I cut my exhaust in half and my bike vibrates more than most so it was rattling the plug free... I'll post some video of the bike. It sounds huge  :eek: I really like how it sounds.

Thanks again guys