BMW F650 intermittently firing?

[Icemaestro]

Hi, have a bmw f650 1997 that i filled up on Friday 5min from home, right at the end I noticed the bike stuttering a bit, like when a bike runs out of fuel. Rode today the 15min to work and it's been getting worse the whole time, and am worried about getting home.

There is fuel coming out, I've drained the floats and they re filled...what else could it be? Loose electrical contact somewhere? It only just had a service by George..


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[unstuck]

Any water in the fuel you drained out?

[Icemaestro]

Nope no water - I have had water in them before hence why I tried that first...


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[unstuck]

I would be looking over the electrics then, especially the earthing points.

[Icemaestro]

Thanks, just for the ignition? as lights etc all stay on. my other thought was maybe there is something blocking some flow of fuel and its not filling the carbs quick enough? might drain the tank and clean it to see if that helps.

[unstuck]

Does it have an inline filter? Or a filter on the petcock? Pull the fuel line off the carb, and see what the flow is like, then do the same with the fule line back on and the carb drain screw undone and the fuel turned on.

[Taxythingy]

Side stand switch? When they fail, they'll sometimes give a sputtering effect but leave the motor running and just get worse over time.

Check the battery terminals, if you haven't already.

[Icemaestro]

Thanks for that one..hadn't thought of the side stand switch...might check ignition and kill switch wiring too. Battery - new and in tight :-)


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[F5 Dave]

I'd still think water in the tank. Bit of meths might help.

[willytheekid]

Do these have built in resistors on the spark plug caps?...I have heard that when they go it makes the engine stutter just like you stated.

edit...I also found this

http://www.f650.co.uk/forums/archive...hp/t-6273.html

[Quasievil]

take the one way valve out of the fuel cap, or if you need to ride home with the cap open a bit.
I had a funduro and this fixed mine (taking the valve out) just dont drop the bike or the fuel will run out albiet slowly

[Icemaestro]

Thanks, my fuel cap doesn't seal anyway, hence the previous water in the bottom of the tank problems (though I've heard this can come through the air filter also in wet weather). this problem has started almost straight after filling it up at mobil the other day though so I'm going for crap in the fuel (since I checked the floats and there was no water in the bottom of them when I drained). should get to it tonight hopefully, or tomorrow evening. It's a good excuse to use the VFR :-P (and I managed to get home yesterday, just took a little longer, choke full on surging etc with a stop every couple of minutes!)

[F5 Dave]

Tank off, drain into bucket & look for 'heavy bubbles' rolling around the bottom.

Probably should avoid Mobil & use BP instead

[caspernz]

Last time I had symptoms like you described I'd filled my dirtbike with diesel...albeit 25 or so years ago. The joys of trucking and biking combined with filling at the same place

Sounds like fuel problem though, drain the tank and check/replace your filter

[Icemaestro]

Fixed...drained the fuel and cleaned the in tank filter...was clear coming out of the main part, but crappy coming out of the reserve, and a whole lot of water...that fixes the short reserve I've had since buying the bike (retarded cyclespot didn't want to hear a word of it and the other 50 million problems I've had in the last 6 months!).

On going to start it up then it would only start on every 2nd or 3rd go, just nothing when hitting the starter half the time, and still having the same problem - feeling like it is running out of fuel. I started at the sidestand switch - no change when shorting those wires, checked the kill switch and cleaned the contacts, no change on shorting the wires here. looked up the wiring diagram, ignition would kill the lights if there was a problem with that, both kill and sidestand switch come back to the 7.5A fuse...pull that out to find 1) there was a 5A fuse in there, and 2) one of the leg bits was snapped - so the vibrations were probably causing it to rattle. Replaced the fuse (with a 7.5A one), now running fine :-)

Thanks all! Mental note. Check fuses first!