TDC marks ???? Fse 400

[Gerko]

Any body know where the tdc marks are for the fse 400 2002/3 model.
As the timing chain snagged and snapped , nothing was marked. Manual doesnt seem to show. I am trying to time the beast

[iancp5]

Originally Posted by Gerko

Any body know where the tdc marks are for the fse 400 2002/3 model.
As the timing chain snagged and snapped , nothing was marked. Manual doesnt seem to show. I am trying to time the beast

I stuck a knitting needle down the plug hole and watched it.
Be very careful with GasGas manuals and the torque settings, some are wrong.

[Gerko]

Cheers , thats the only way i could think of working it out. Surely there should be a mark. Well thats my thoughts and not GasGas's

[Qui-gon]

Assuming the cam chain area was not the issue for the teardown you should always verify the marks at tdc firing stroke. If it is not obvious you can then mark it up yourself using an engraver or centre punch. That way you can always put it back as it was

[Gerko]

The cam chain was the reason for teardown. Looking at the stator side its marked evenly, so am i right in thinking it sparks twice??. If not how do i work out which is the firing stroke, Im sure ive read it fires twice.

[iancp5]

Originally Posted by Gerko

The cam chain was the reason for teardown. Looking at the stator side its marked evenly, so am i right in thinking it sparks twice??. If not how do i work out which is the firing stroke, Im sure ive read it fires twice.

That confused me too and I came to the same conclusion, it must fire twice.

[Qui-gon]

As that is the only trigger and occurs every revolution I believe its the ecu which works out which spark to miss or not. I also think that the ecu works out when to open the injector once as with the spark otherwise there would be 2 injector pulses (not good) as well as 2 sparks which is not unusual

[iancp5]

Originally Posted by Qui-gon

As that is the only trigger and occurs every revolution I believe its the ecu which works out which spark to miss or not. I also think that the ecu works out when to open the injector once as with the spark otherwise there would be 2 injector pulses (not good) as well as 2 sparks which is not unusual

There is nothing as far as I can tell for the ECU to determine which is the firing stroke so how can it work it out? There's no camshaft sensor, it seems a very simple system.

It is possible both injector and spark are "wasted". I don't think the bikes attempt to comply with emission regs like a road bike and the injector is farther back than many road bikes so maybe the buffer effect of the inlet tract smoothes it out so it works good enough. Of course if they did it properly we could probably get much better mileage!

[Qui-gon]

Both scenarios are possible I guess. It would be possible to set the injector pulse and spark whilst cranking....could explain why these bikes never burst into life on the first compession stroke whilst cranking? As there is little or no information about these ECUs around, except on one of the Fiat forums, it will be difficult to find out. But I am going to find out. Just waiting for a piece of kit to arrive!

[Gerko]

well i have a 50 / 50 chance of getting it right if they dont fire twice, i will update accordingly. If it fires though i wont be taking it apart to see if i just guessed right