Totally Flummoxed New thread

[chasbmw]

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Time to open a new thread. Following on from my thread about refitting an exchange starter motor to my 2004 Rockster based trike:

I’m totally Flummoxed
Henry and I had a good fiddle with it this morning. With a properly charged battery the bike turned over well, starter working properly dropping down to around 10 volts under load.
Pulled a couple of plugs, sparking well.
Pulled both injectors, plenty of fuel
The bike obviously has compression
All fuses good. No burnt coils to be seen

Issue with the bike started after a very hot ride on Thursday, stopped for lunch
Bike did not restart. I probably buggered up the starter motor in trying to restart it.
So why is the bike dead, it has sparks compression and fuel. But no start.
If the hall sensor had failed, surely I wouldn’t have sparks?
Any sensible ideas.

A bit of background: ultra low mileage trike, very few miles in the last 10 years: it seemed to work fine, but as a precaution I replaced the in tank fuel lines and fuel filter, big O ring on the pump assembly done at the same time. New plugs fitted and valve clearances checked ( very little adjustment required, covered approximately 150 since the work was done.

it’s a trike so local independent workshops won’t touch it and doubtless the same for main dealers.

Thanks for your help guys

Charles

 

[Steptoe]

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If the hall sensor had failed, surely I wouldn’t have sparks?

You’d think so wouldn’t you …

But as I’ve posted a few times previously (as recent as last week) I’ve had customers bikes that would start and idle perfectly all day long if need be.
One touch of the throttle and engine stopped instantly.
First one I had I changed lots of parts, with no difference. In desperation I fitted another Hall sensor. Bingo. Problem solved.
Since that first bike with that peculiar problem I’ve a had few in suffering the same.
I now recognise the symptoms.

Of course, that’s not to say it could be the ECU

 

[chasbmw]

Thanks Steptoe, looks like that’s the next round in the parts cannon

 

[Ian J Hartley]

I would go with a Hall sensor first.

However, When you got a jump start from the car. Was the car engine running.?

I ask because the massive current surges from the process, could have damaged your ECU.

You should only ever jump start from a vehicle’s battery with the vehicle engine off.

 

[chasbmw]

I hope not… I seem to remember that we jump started with the engine running, but whatever the fault was it was present before the bike was jumpstarted. Main symptom was 50 mile run in 30c heat, bike left in the sun for 40 mins No Start!

 

[jefformston]

I would go with a Hall sensor first.

However, When you got a jump start from the car. Was the car engine running.?

I ask because the massive current surges from the process, could have damaged your ECU.

You should only ever jump start from a vehicle’s battery with the vehicle engine off.

The instructions I got with my jump leads state the donor vehicle engine should be running before trying to start the vehicle with the flat battery. Attach leads with engine off then start donor vehicle.

It’s they way I’ve always done it.

 

[Ian J Hartley]

You may be lucky, but something to consider if a hall sensor does not fix your initial problem.

 

[Ian J Hartley]

The instructions I got with my jump leads state the donor vehicle engine should be running before trying to start the vehicle with the flat battery. Attach leads with engine off then start donor vehicle.

It’s they way I’ve always done it.

In the olden days with the Kettering ignition systems, it didn’t matter, but modern vehicle all have engine management systems and in many cases multiple ECU’s. These devices all have integrated components that do not survive high voltage and high current spikes. While many will have protection from these surges. You’re taking an unnecessary risk doing it your way.

If you don’t believe me Google it…….

 

[Riceburner]

The instructions I got with my jump leads state the donor vehicle engine should be running before trying to start the vehicle with the flat battery. Attach leads with engine off then start donor vehicle.

It’s they way I’ve always done it.

If jumping a car from a car, then that's fine. (Which is most likely the scenario assumed by the instructions for the jump leads).

If jumping a bike from a car, then the car battery by itself has more than enough oomf to start the bike without the car engine needing to be running, and without any very high voltage surges from the car possibly causing damage to the lighter weight electrics of the bike.