CBF600 2006 turning over but not starting - help requested

[dfligs]

Hi all, I have been having trouble starting my Honda CBF600 2006 for the last couple of months and have tried a whole host of fixes to resolve this issue to no avail. Therefore, I have come to you to see if anyone can provide any suggestions for a fix.

Problem – Bike turns over but does not start (Note: I have had it starting once or twice using starter spray however as of today even that does not work and it dies after a few seconds)

Symptom – Bike doesn’t start and I also noticed I can’t hear any noise that would indicate fuel priming (i.e. a click or a whirring noise)

What I’ve Tried:
1. Ensured the battery is fully charged
2. Changed fuel
3. Cleaned spark plugs and checked they spark when rested against the body
4. Removed air filter and sprayed starter fluid directly into the throttle body/carbs (with and without the fuel tank on)
5. There is a pink cable going into the ECM that I think is from the ignition switch, I was not reading the expected 9V on this and so I cut the cable and fed 9V directly into the ECU to bypass the Zener diode – hopefully someone can tell me if I had the right cable for this
6. Checked all fuses for burn out and continuity

Things I would like to check:
1. Angle tilt sensor – Couldn’t locate this behind the dials – also couldn’t get the ignition switch off because a screw was threaded
2. Clogged carbs – big job taking the carb off and cleaning so haven’t got round to it yet
3. Fuel pump activates when manually applying 12V – Think I found it but couldn’t see any wires going into it to apply 12V to
4. Starter relay switch – assumed this was working as engine is turning over
5. Engine stop switch – same as above
6. Clutch switch – same as above
7. Side stand switch – same as above
8. Bad ground/earth going into the yellow connector – unable to find
9. Fuel cut relay – not got round to this

Notes:
• Headlight is working

Thanks in advanced.

[Robby]

I'm not seeing a fuel pump in the parts diagrams, it looks a normal vacuum fuel tap with a gravity feed to carbs on a 2006 model.

Seeing as it does sound fuel is the problem, open up a drain screw on the bottom of a carb and see if fuel comes out. If you get a couple of teaspoons per carb and it looks nice and clear, then you have good fuel at the carbs. If it's dark or full of water, then you had bad fuel in the carbs.

After draining out what is probably quite nasty stuff, close up the screws and try to start it. It will take 10-20 seconds to refill the carbs from the tank.

That should do it. You have spark, we can assume you have enough compression to start. The carbs might be full of shit, but usually enough gets through for it to run a bit.

I'm also assuming you checked for spark after your wiring job.

[dfligs]

[Robby]

https://www.cmsnl.com/honda-cbf600sa-2006-6-england_model7971/partslist/#.Xt6uOkVKg2w

Drain the carbs into a cup and have a look at what comes out. Old petrol is dark and smelly. Water will show up as little dirty droplets rolling around at the bottom of the cup.

Then check spark again, because you've been cocking with the wiring which probably wasn't necessary.

Then crank it like you're trying to start it. Vacuum petrol taps only let the fuel flow when they see vacuum, so you need to crank it long enough for it to open the fuel tap and let the fuel run down the lines to the carbs.

I would also not use the choke, you'll end up flooding it. The aim is not to start it up and ride off into the sunset, but to get enough of a cough out of it to sound encouraging. Feel free to mess around with the throttle while you're trying to make it start, the small holes that meter fuel and air for idling are probably also clogged with shit, at least partially.

[colink98]

my 2004 CBF600 is very picky about starting from cold.
Any throttle at all and it will not start.

choke has to be fully out
no throttle at all
turn over it it will fire up.
keep the choke held out until the revs pick up.

even then too early on the throttle will cause it to stall.

it really is sensitive when starting up.
but once you get the hang of it she starts up every time.
____________________
PCX125 (stolen) - CBF600 (current)
Ride it like you stole it.
ride sensible and not like an idiot and you wont get 6 points in one week.

[dfligs]

OK update time and fortunately it is good news!!!

We checked the spark plugs and gave them a clean and at the same time we noticed that spark plug 3 and 4 were the wrong way round (strange that it ever run like this). So of course we corrected this.

We then drained the carbs and the fuel looked good except for being more yellow than new petrol we had recently bought and to me it seemed slightly oily to touch. Therefore we are suspecting that maybe diesel was put in incorrectly at some point.

After a hefty amount of cranking with breaks to not destroy the starter motor it burst into life and is now running perfectly. Took a lot of full throttle to keep the engine going while it was clearing all the crap out.

Thanks for everyones help in solving this issue,

Oh and we checked the compression and that seemed to be OK as well.

I'm assuming the order of the spark plugs is extremely important. Do you expect the engine to be able to start at all if for example 3 and 4 were mixed around? (out of interest)

[Svenington]

I've found a can of carb cleaner does wonders when doing up my Yamaha that's been sat neglected for years by the previous owner.

The order of the spark plugs/leads is definitely important - your bike's designed firing sequence is 1, 2, 4, 3 so if you swap 3 and 4 around you're going to be essentially running on 2 cylinders as the other two will be firing at the wrong time. You might get lucky, I've had some 2 stroke outboards running on 1 out of 2 cylinders, but it will run pretty rough and will definitely struggling with crappy fuel too.