Over fueling problem on Kawasaki ER5

dannymccann

Bit of a long shot but here we go! I've got a '96 Kawasaki ER5 commuter motorbike. Recently developed a terrible hesitation between 1k - 5k RPM in every gear, which makes it impossible to ride. It's really dangerous especially when turning against the traffic as you will get half way across and then it just dies (but doesn't stall). It stutters, burps, farts, misfires, the whole nine yards. So far to fix it I've done:

- Carbs off twice, blown through with an airline (everywhere)
- New plugs, caps, leads and coils
- New air filter, there isn't a fuel filter
- New fuel tap diaphragm
- Different fuels, tried with the tap on ON, PRI, RES
- New fuel pipe on reserve line as previous one had perished, other pipe looks fine but got a couple of jubilee clips on the way to also replace it in due course
- Checked fuel lines for kinks and bends, nothing
- Carbs balanced with a vacuum gauge, they are both spot on
- Carb diaphragms in good condition
- Carb float height set back to 17mm (it's actually 17.2mm on the vernier) as per service manual (which specs +-2mm)
- Plug gap was bang on at 6mm, still ran like !!!! so moved it to 7mm and no difference
- Inspection of the old plugs revealed black deposits on left cylinder and normal colour on right, now looking at new plugs both are black (which would indicate overfuelling???)

Just cannot get it to run right - idles perfectly, starts perfectly even on a freezing morning or after being left for a week as per this morning.

Any ideas?!

BeenThroughItAll

Carb needles worn?

Jets been replaced in the past with larger ones?

Moto2

These sort of problems aren't unheard of on the ER5

Have you checked the fuel lines are clear internally, blown through with an air line?
Check for a vacuum leak
Were the carbs balanced to start with or did you have to adjust one?
Check the air pilot adjustment

I'd strip everything from the fuel tap to the carbs and ensure everything is clean and there are no air/vacuum leaks

=rizla=

Does it do it all the time or after you've been riding for a while? If its all the time then you've done everything I can think of so cant help. However if its happening after a few miles could it be carb icing?, I had this problem a few years ago on an old bike, the only cure I could find was an additive called profst.

facade

Has something happened in the exhaust, like a baffle corroded and come loose so it is partially blocked?

Seems the exhaust is the only major part that you haven't checked.


Not messed with an ER5, but my experience of earlier Kawasakis is terrible corrosion problems on the wiring, they did have a habit of putting the ignition box under the headstock, right where all the salty water sprays at it from the inadequate mudguards.

dannymccann

Carb needles worn?

Jets been replaced in the past with larger ones?

Needles have been out and inspected twice in last 2 weeks when we've stripped carbs down for blow out, they looked fine

No idea about jets, I haven't replaced them and it's been running OK since I bought it 2 or 3 months ago

Have you checked the fuel lines are clear internally, blown through with an air line?
Check for a vacuum leak
Were the carbs balanced to start with or did you have to adjust one?
Check the air pilot adjustment

I'd strip everything from the fuel tap to the carbs and ensure everything is clean and there are no air/vacuum leaks

One of the lines from tank to carb is brand new, other is old but fine. We haven't blown through other pipes on the carb if I'm honest but it appears to be overfueling because of the black plugs.

Mate hooked his vacuum gauge up to carbs to check the balancing - no adjustment has been done

Dont think we've touched the air screw.

I'm not a mechanic (the person doing the work is a car mechanic for Toyota but sorts his own bikes out, and mine) but I've been watching what he's doing and he has stripped everything that you can see that is in the carbs that you can take off or apart. Had a look down into the cylinders and there is no fouling in there (looks clean as a whistle). Tap was stripped out and had it's internals replaced with new diaphragm and gasket.

Does it do it all the time or after you've been riding for a while?

Problem developed one the way home a week ago and has been like it ever since. Unrideable so has done about 5 miles since problem started as too dangerous to ride on the road!

Has something happened in the exhaust, like a baffle corroded and come loose so it is partially blocked?

Could be something to look into I suppose, exhaust doesn't sound any different however.

dannymccann

Also, choke doesn't appear to be sticking and the float bowls bounce around as they should (as in they aren't stuck or anything like that, they can move freely with the flow of fuel)

arcon5

You checked compression?
Not necessarily over-fuelling based on the plugs, more missing

facade

arcon5 wrote: »

You checked compression?
Not necessarily over-fuelling based on the plugs, more missing

Exactly, it could be overfuelling or just not firing, and it has just happened, so either a float has stuck and it is flooding, the exhaust has collapsed, or it is electrical.

facade wrote: »

Not messed with an ER5, but my experience of earlier Kawasakis is terrible corrosion problems on the wiring, they did have a habit of putting the ignition box under the headstock, right where all the salty water sprays at it from the inadequate mudguards.

On my Honda, there is a position sensor on the side of the carb to tell the ignition what the load is, it won't rev properly if it is disconnected (found that out when I took the carbs off to sort the seized choke and forgot to put the connector back)

Also Kawasakis tend to have problems with the sidestand switch, but that usually stops it running all together when it is in gear, and most have been bypassed by now.

Strider590

I would put money on a vacuum leak at the seal between carb and inlet manifold. If in doubt, replace it, I spent years tracking down a similar problem on my kitcar.