Kawasaki ER5 Jerking When riding (Not in Neutral)

[twinterx]

Hi,
I recently bought an Er5 off the riding school which I did my A2 test with.

I have fit a restrictor to it to restrict it to 46.6bhp.

I rode it out a couple of times, when on some blasts round my local area, it ran beautifully, no issues what so ever.

I havent rode it in a few days. It was very cold today, took some going to get it idling when I started it.

I rode for about 2/3 minutes out of my village perfectly, no issues. Then as I geared down the bike started jerking. Like it was running out of fuel intermittently.
I pulled over, sat it in neutral, it idled fine, I revved it through the rev range, no jerks.
Put it in first, rode off, and it jerked again... and all the way home.
Could it be just that it is cold?

Any ideas?
Thanks, Tom

[jaffa90]

What have you fitted and where?
Is there unwanted air going in where it shouldn't ?

[stinkwheel]

Does sound like fuel starvation, misfiring under load but running normaly at a standstill (you use loads more fuel when under load).

I normally harp on about electrics usually being the main problem when bikes misfire but this COULD be a fuelling problem. It could also be water in the fuel or a blocked tank breather (many other things it could also be).

So you can check for water in the tank by looking in the tank with a torch, it would form a layer or "bubbles" on the bottom. Eliminate a blocked breather by riding it with the fuel cap open and see if the problem goes away.

My KLE500 (practically the same engine as yours) did develop a fault recently where a load of corrosion had formed on the needle valves in the carbs, jamming them in place. Mine were WELL stuck and needed physically removing and cleaning. Slightly stuck ones might be shifted by tapping the sides of the float bowl with a lump of wood. I'm still blaming ethanol in the fuel for my problems.

Another thing those bikes were prone to was carb icing. The circumstances don't seem to fit (normally it causes the engine to die or misfire when you back off after a period of sustained high-speed riding in icy, damp conditions). They are fitted with a carb anti-icing system to prevent this. Coolant is routed round the back of the carb float bowls. There is an inline filter in the hose delivering this coolant that can become blocked.

You may land up pulling and cleaning the carbs but also check condition of the fuel filter, fuel tap and fuel hoses first. Early models (pre '96) could have significant degradation of the fuel lines and gauze filter in the tank due to the afore-mentioned ethanol in the petrol.
____________________
“Rule one: Always stick around for one more drink. That's when things happen. That's when you find out everything you want to know.”
I did the 2010 Round Britain Rally on my 350 Bullet. 89 landmarks, 3 months, 9,500 miles.

[Teflon-Mike]

Before getting too deep in spanners... they change the petrol over in the petrol stations around september/october and march/april from 'summer; to 'winter' grades; and its actually a statutory requirement I'm told.

Kawasaki's in the early 90's suffered a widely published recall due to 'carb icing' issues in the colder months... and I have encountered a few folk who have had this niggle reccur on bikes that were grey or parallel imported and not subject to recall... and most often this time of year when the petrol grades swap over and they still have summer fuel in the tank when it gets nippy....

It MAY be worth giving the thing a good blast and running it onto reserve and as far on that as you dare to drain the tank of as much 'summer' grade fuel as you can, and then fill up at a popular filling station that aught by now be on winter grade... go for another ride and see if problem 'clears' on its own.
____________________
My Webby'Tef's-tQ, loads of stuff about my bikes, my Land-Rovers, and the stuff I do with them!
Current Bikes:'Honda VF1000F' ;'CB750F2N' ;'CB125TD ( 6 3 of em!)'; 'Montesa Cota 248'. Learner FAQ's:= 'U want to Ride a Motorbike! Where Do U start?'

[Rogerborg]

[twinterx]

Update.

Took it out again tonight after letting it warm up for 10 minutes.

Jerked again, alot... Noticed today that after longer periods of the engine shutting off, it backfires. Sounds like fuel, any ideas where the fuel filter is ?

[MahatmaAndhi]

From memory (it's too dark to check,) it's right on the front, under the horn.
____________________
2008 Aprilia Sportcity 250

[stinkwheel]

[TheManWithThe...]

the fuel filters are threaded into the tank itself. they can be accessed by removing the tank and simply undoing the bolts. That could also be an opportunity to swap out any potentially contaminated fuel for fresh stuff.

My er had a short episode of sporadic surging that came from an a carb balance problem resulting in one cylinder being starved of fuel.

Once the tank is off, checking the for any fuel line blockages should be simple (although the fuel tank can often be the cause of trapped pipes).
____________________
MBK Nitro 50, Sold. Kawasaki ER-5, Honda ST1100
"Anyone can jump a motorcycle! The trouble begins when you try to land it..."

[doggone]

[stinkwheel]

[mentalboy]

[twinterx]

I havent found the time to fix it yet.

I was going to ask though, is there fuel additives which clean the system these days?
If they dont work, then no problem Ill have to open it up.

Another note which I completely forgot to mention!
When fitting the restrictor. I accidently left the fuel tank in such a way that the fuel leaked overnight. This ran it pretty much dry.

My thinking is that it disrupted some dirt/rust from the tank and it clogged the filters after I took it for a ride and let it settle for a few days.

[twinterx]

Okay, so this evening i took the bike to my mates house to work on it in his garage.

On the way there, rode like garbage as expected..

Started by taking the tank off and draining it. Only to check the fuel filters, they are fine....

Looking around, saw that the filter for the Coolant was vile.
The little pink pellet thing had the bottom third black. The filter was clogged, it was vile...
Cleaned this out, threw it back together... Put about a litre and a half of fuel in, but accident pierced the reserve tank line. Fuel went everywhere.
Immidietely took the pipes off, stopped the spillage.

But the fuel line down past the pierce(about 1cm) and re attached the pipe.

Had the bike running fine on reserve. In my haste to see if the coolant fix had fixed my issue, i took the bike out, forgetting to fill the tank up!

It seemed to ride much better! holding speed well, not jerking around nearly as much!
I then ran out of fuel.....

After putting more in, switching it to prime, and trying to start the bike... nothing...

The bike would not start....
tried periodically throughout the hour. Nothing.

Hoping its flooded... my mate will try to start it in the morning.

A few questions:

If it was carb icing, would it still be mis firing a little to begin with? Would this iron out after a few minutes riding?
OR is the jerking likely to be due to lack of fuel and it could be that my issue is now fixed..
Why wont my bike start? My issue with believing its flooded is that, it went from empty, to flooded, without starting?? how is that possible..

[Azoth]

[pompousporcup...]

i was under the impression carb icing was only really prominent in very cold conditions and under engine load, where there is lots and lots of cold air passing through the carbs that cause them to freeze/ice and wouldn't expect it after a bit of idling and when trying to get up to speed..

[twinterx]

[RhynoCZ]