Super bad misfire

[Ian Castleton]

Out on my 2005 V11 injected Le Mans yesterday - about 30 degrees C.  Haven't used it much this year due to back brake woes.  Running like a dream until around 10 miles from home, when bad misfire started, losing almost all power.  Managed to limp home with much clutch slipping and throttle, keeping revs above 3000 rpm.  Sounded like it was only firing on 1 cylinder,

 

Started bike again after about 30 mins of cooling down.  Plugs fine, but would only tick over on LH cylinder.  Started fine again, so went out again but after a couple of miles developed misfire again, and just managed to limp home.

 

Any suggestions where to start looking?  Fuel filter, bad fuel, temperature sensor?  Why should it suddenly start after running well?

 

TIA, Ian

[JBBenson]

Check your coil to plug wires, remove and clean, may be corrosion in there. 

 

Could be bad coil, or water got into one of them through a crack.

 

If the bike was sitting, could be clogged injectors due to old gas, some crud broke loose and clogged one injector.

 

I would do this:

 

1.

Drain and add fresh gas

2.

Make sure the battery is good, and is fully charged. Weak batteries can cause symptoms that don't make sense.

3.

Check coils and plug wires, clean and sand the contacts lightly with emery paper to remove any corrosion

4.

Pour in some Redline Si-1 fuel system cleaner.

5.

If you can get it running on both cylinders, do "Italian Tune Up"

 

If none of these work, maybe do complete tune up:

 

https://www.v11lemans.com/forums/index.php?showtopic=19610&page=1

 

It is bad for any motor vehicles to sit around for too long without being used. It is usually bad gas and crud, but in your case might be bad/contaminated coil.

[antmanbee]

If the plugs look fine then it is not losing spark on one or both cylinders unless it is also losing fuel at the same time. Investigate the circuits that go from the battery to the side stand switch and relay and then to the ignition switch and kill switch. As per kiwi-roy, put a bulb wired from Fuse 8 to ground and see if the bulb stays lit when the engine cuts out. If it stays lit then the side stand switch and relay and  ignition switch and kill switch are good.

If it flickers then one of those components are faulty.

The timing sensor near the timing cover on the front left of the engine could be going bad. if it is cutting in and out you will lose both spark and fuel simultaneously. 

[Ian Castleton]

Thanks JB, I'll check these out

[Ian Castleton]

Thanks antmanbee, the timing sensor has caused starting problems in the past.  I'll check that out too

[docc]

If the plugs look fine then it is not losing spark on one or both cylinders unless it is also losing fuel at the same time. Investigate the circuits that go from the battery to the side stand switch and relay and then to the ignition switch and kill switch. As per kiwi-roy, put a bulb wired from Fuse 8 to ground and see if the bulb stays lit when the engine cuts out. If it stays lit then the side stand switch and relay and  ignition switch and kill switch are good.

If it flickers then one of those components are faulty.

The timing sensor near the timing cover on the front left of the engine could be going bad. if it is cutting in and out you will lose both spark and fuel simultaneously. 

Oi! Kiwi_Roy's --> Go_Winkie! 

 

 

Lately, mine's been giving me "indications" . . . 

[fotoguzzi]

also be sure you don't have air leak at one of the intake manifold boots. if it's one side only suspect that coil or it's wiring.

[Ian Castleton]

Thanks fotoguzzi.  Will check out the manifold boots with all the other suggestions ...

[Ian Castleton]

So, after much checking, I drained the tank, filled it with super unleaded (UK high octane) and a good dose of injection cleaner, and it now runs like a dream and sounds magnificent.

 

Fixed the tickover by adjusting the air bypass screws to one turn out (they were nearly right in), and I've given it several rounds of "Italian Tune Up".  Thanks for all your help everyone.

 

One further thing.  Over the years I've had problems with starting, even when warm.  The fuel pumps runs for a few seconds, but pulling in the clutch and pressing the start button does nothing.  Push the bike back into garage, onto its stand, try one more time and the bugger starts.

 

Today I've worked out what's up.  Sitting on the bike with the front wheel straight ahead and it won't start.  On the side stand with the front wheel to the right, and it does. Must be a connection on the clutch switch or starter button cable which only makes when the front wheel is not straight.

[Chuck]

There are a couple of bullet connectors on the left side up by the steering neck. Take em apart, spray with DeOxit, put em together, wiggle them around.. oh.. you know.

Forget about them for several years.

[LowRyter]

check that the TPS didn't get unplugged.

[docc]

There are a couple of bullet connectors on the left side up by the steering neck. Take em apart, spray with DeOxit, put em together, wiggle them around.. oh.. you know.

Forget about them for several years.

This and making sure they have a tight fitting crimp, then seal them over with a generous length of heat shrink tubing for each.

[Ian Castleton]

Thanks guys, will check these out 

[Tomchri]

You did say it had a different behavior when you turned the front Wheel,,, did you check the wires in the ignition Lock ?

Cheers tom.

[leroysch]

Ditto on this.

 

I hadn't left enough slack in the harnessing going into the ignition switch during my foray into switch lubrication.  At full lock, I was able to disengage the removable bottom "cup" of the ignition switch assembly. Exhibited the same symptoms...