Gixer SRAD hot starting/running issues?

[imdying]

Any chance you've overtightened a valve?

[centaurus]

Any chance you've overtightened a valve?

It's not impossible, but then it would not die instantly (it would run unevenly or at least complain before dying) and it wouldn't be a spark problem, would it?

Plus, when starting, it starts incredibly fast, which means the compression is there and is good. With an overtighten valve, I would have compression leak and it would either idle rough or take its time to start. Correct?

[SS90]

I am surprised thatvno one has mentioned this, but I from the symptoms you described, I would suspect that your ignition pick up (reluctor) is the culprit.

It is a small pickup, located on the end of the crankshaft.

If memory serves me correct, it is under the right hand side front engine cover on a 99 GSXR, behind the starter gear.

This little pick up is responsible for signaling the ECU when each cylinder is due to spark, in relation to crankshaft position.

Over the years, most every manufacturer has had trouble with these wee sensors, and the common faults seem to manafest when the engines are hot.

Normally, the windings in the magnetic coil, responsible for the signal develop an internal short when they get hot, making the signal essentially "out of range" for the system, basically having the same effect as if it was not even there.

I seem to remember that the GSXR's (what is the collective term for GSXR's by the way) have a single wire pick up, meaning that measuring the resistance can't easily be achieved.o

With a two wire system you can measure this when the engine is cold (sparking), and Hot (not sparking)

manufactures specify an Ohme range.

For the single wire systems, some times the process is a little different.

There are several manufactures BMW, Piaggio, and so on, that have a plug in ignition pick up sensor testing box, basically you plug the sensor lead into the box with the unit on the bike, and crank it over, if the LED on the box lights up, the sensor is working..... These test boxes are not manufacturer specific generally speaking, and you only need to connect the wire, and turn it over to test.

You may need to take the bike to a workshop, if money is an issue (NZ bike shops do have a high labour rate these days), you can save a few bucks by removing all the bodywork.

My gut feeling is that the pick up is the culprit.

[MSTRS:Me]

It's not impossible, but then it would not die instantly (it would run unevenly or at least complain before dying) and it wouldn't be a spark problem, would it?

Plus, when starting, it starts incredibly fast, which means the compression is there and is good. With an overtighten valve, I would have compression leak and it would either idle rough or take its time to start. Correct?

Nope. Would only show up (unless valve stem is under pressure to start with) when temperature causes metals to expand.
And you are right about not being an effect on the spark.

[MSTRS:Me]

SS90 - you mean the Crank Angle Sensor? Wouldn't this be monitored by the ECU and show as a fault?

[SS90]

SS90 - you mean the Crank Angle Sensor? Wouldn't this be monitored by the ECU and show as a fault?

In some circles, yes,it is reffered to a Crank angle sensor (one of those parts that known by many names)

I too would have thought that it would be monitored by the ECU, but I have seen more than one self diognosis feature not register faults such as these.

Many modern mechanics have come to rely on fault codes and such like, and some of the old fault finding skills have long been forgotten.

For me, the clue is in the not sparking.

With a fuel injected bike, you generally need a crank angle sensor, as well as a camshaft position sensor, quite often the camshaft position sensor is only needed to start the bike (after the ECU has established the camshaft position in relation to the crankshaft, it becomes redundant), so in this scenario, I would not suspect the camshaft position sensor as faulty (if it where, it would only create a fault after shutting down, not cause a fault where by the bike actually shuts down, as the crankshaft sensor would)

The fact that the fault is 100% repeatable, and, totally dependent on temperature, as well as manifests itself by causing the coils not to fire eliminates things like fuel pump, injectors an so on.

The fault is something related to signalling the coils to fire, the ECU is unlikely to be at fault...... The symptom is too dependent on mechanical temperature, I suggest that something physically bolted to the engine, that is assosiated to the ignition system is at fault.

[MSTRS:Me]

Something to be aware of...
Often it is the simplest things that are overlooked.
A while back, I was having a problem too. Not one that stopped the engine, but had no other symptom apart from triggering the F1 light. At least until the speedo/tacho needles would drop to zero, and then the F1 light would come on. Fault code/s showed the problem to be 'loss of power to the injectors'. All four of them. Yet the engine never missed a beat. Hmmmm...
Remembering an intermittent problem I had with my Commodore, I cleaned the battery terminals on the GSXR. Problem fixed.
ECUs are very sensitive to changes in voltage, and heat increases resistance in wiring, right?

[MSTRS:Me]

The fact that the fault is 100% repeatable, and, totally dependent on temperature, as well as manifests itself by causing the coils not to fire eliminates things like fuel pump, injectors an so on.

The fault is something related to signalling the coils to fire, the ECU is unlikely to be at fault...... The symptom is too dependent on mechanical temperature, I suggest that something physically bolted to the engine, that is assosiated to the ignition system is at fault.

You could be onto something here.
Or one of us is...

[centaurus]

In the end I have acknoledged my limits and taken it to the shop. Now I'm waiting to see what they find.

[centaurus]

I took it to the shop and it turned out to be the camshaft position sensor. After they replaced that it worked fine...

So I took it for a test ride on the south island this weekend. It ran ok for close to a thousand k's then it decided it can't calculate properly how much fuel it needs anymore so it will use twice the amount it needs. I barely made it back from chc.

First I thought it was running on only 3 cylinders but a spark plug inspection showed all four were sparking but all of them were covered in that dry black dust/powder that indicates an overly rich mixture. Plus, the smell of unburnt fuel that I left behind me all Sunday was speaking for itself

I suspect this last issue is not related to the initial one but rather a failure in one of the sensors that dictate the fuel mix (oxygen sensor or vacuum sensors). So the bike it back in the garage and I'll have to check all wires and vacuum hoses before I make any decision as to what needs to be done and whether I need to take it to the shop and fork out big bucks again

Thanks guys for your suggestions. Looks like some of you were quite on the money, and the ones who weren't made very valid and valuable suggestions. It's good to know the art of motorcycle maintenance hasn't died yet in NZ (I posted on some US forums and got no reply at all).