Forum

[Nettshubby]

My vote still goes for water in tank/carb.

[Gwilly]

EFI choke problem? Not sure how they work on the modern bull but i have on occasion knocked on the enricher lever (mikcarb) with my riding boot..

Spits and farts on low throttle but picks up on wot.. Check linkage for salt corrosion, any moving part gets the WD40..

Certainly looks way too rich at normal temp.. Also some people let the bike tick over with choke whilst they put on riding gear..

Just my theory that its a good way to kill a plug with this modern petrol..

[zippy]

Yup, - That's black! Probably gets worse as you go up the centre electrode... The tip centre is suprisingly clean and white - suggesting that it is running a little weak - once your cold/ choke start has burnt off and the engine is hot. Check all your carb/ head joints for leaks.Also jets for blockages.I would also check the size of the main jet and needle height while youre in there. Keep an eye out for the presence of water too. Droplets in the floatbowl, excessive corrosion of the floatbowl floor - (It means water is there regularly). Lastly check the tank, filter and fuel lines. Be aware if you are using cheap supermarket fuel with alcohol in it, if you let it stand over the winter any cold damp air in the tank will combine with the fuel. The alcohol will more readily mix with the moisture in the air than the petrol. once it is out of solution, the alcohol/water droplet will sink to the bottom of the tank and be the first thing to travel down the fuel line to the carb....

[Michael]

It's an EFI bike... no carb. Will check the enricher device thingy - it has seized before, and didn't seem to have much effect when I fiddled with the lever whe the bike started coughing. Fuel line is pretty new, but will check that too. Do I check for air leaks the same way as I would on my car i.e. carb cleaner sprayed onto any suspect areas and listen for a change in engine noise?




Also, how does one check for a head gasket leak (is that what you suggested Zippy?) on an aircooled bike? I am leaking a bit of oil from the exhaust rocker cover, and this is collecting at the base of the cylinder. Not much, just mucky.

[Gwilly]

Zippy can speak for himself if i'm wrong but i sure he means the manifold joint carb to head which are a known trouble spot on carb versions..

Was thinking also about the wire connections to the sensors, The one on the exhaust for instance, a poor corroded connection must play havoc with the electronics..

Maybe a quick check and spray cleaner would not be wasted effort... Cant rule out water in fuel but it just looks as if the cold start is not coming off with engine temp increase until its been running for some time.. Just a thought anyway..

[Michael]

I suppose it could be sticky cold start cable, a sticky cold start piston thingy, or a badly seated cold start cable? All worth a check, and helped by the fact that Thack worked out how the cold start mechanism works on these bikes a while back

[Thack]

Michael writes: "It's an EFI bike... no carb. Will check the enricher device thingy - it has seized before..."



There is no enricher device on the EFI bike. It opens an air bypass around the throttle plate; in other words, it's a simple, manual fast idle control. It does exactly the same thing as unscrewing the idle speed screw a turn or so, except of course it's a load more convenient.

[Gwilly]

Dahh! enlightenment, cheers thack, So this will not enrich mixture if stuck in on position..

Sooo, does the efi enrich mixture dependant on the signals received from the sensors? ie temperature and throttle position..

[Michael]

Presumably, if the enricher device thingy (air bypass thingy - whatever) is stuck in the 'on' position then it is chucking a whole load of extra air past the throttle air meter sensors (are there any?!), which is compensated by a whole extra bunch of fuel by the o2 sensor in the exhaust, thus resulting in a rich mixture... much in the same way that an air leak in the intake of a car EFI engine can result in a rich (not lean) mixture...




Or is that all guff?

[Michael]

And to figure out how to fix the issue... should I take the throttle body off and clean it to bits, refitting and reseating cables etc... or should I hit it with a hammer? Essentially, once the problem has been identified - what is the fix?




BTW I am open to any hammer suggestions!!!