Triumphrat

thebiglad

As I understand it, the control in question merely increases the idle, no switches, no butterfly valves.

As for how it increases idle I can't tell you, but it just does and that's enough for me.

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Bonny - '10 Bonneville T100 with saucy Dominator pipes, de-snorkel'd, de-AI'd, UNI air filter; De-O² sensors.

2004 Jaguar S-type V8 4.2

Forchetto

It opens a small air passage that bypasses the throttle butterfly, thereby raising the idle speed.

sprouty115

OK, so unless there is some feedback loop I see no way that it could cause the starting issue we're discussing. This has to be related to the battery as stated above.

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- Stephen

Captain Bert

Problem: motor fails to start - pressing starter PB causes partial cranking then stops even with start
button still fully depressed.

Action: to monitor and carry out Cranking Volts Survey.

Test equipment: Fluke 89 IV multimeter with Australian NATA test certification (readings are within specifications) using Auto DC volt scale, meter set to Fast min/max recording

Test Study : Bonneville T100 2012 1042km, Battery condition - as new Battery voltage no load - 12.595v
Battery voltage: Ignition ON - 12.163v

Motor start min Volt recorded Motor start status
Crank test 1 - 7.14v FAILED to start
Crank test 2 - 7.10v STARTED
Crank test 3 - 7.17v STARTED
Crank test 4 - 7.24v FAILED to start
Crank test 5 - 7.14v STARTED

Battery Volts after 5 crank starts - 12.43v

Results: somewhat surprised the battery volts fall so low at initial cranking start. As a Electrical Technician I do understand the principal of what is happening here. The starter motor at point of start is in a stalled position, meaning there is no magnetic field
built up in the armature, therefore the battery sees the motor as a purely resistive load until the armature magnetic field reaches saturation point and impedance of the circuit restricts current. so not having measured the motor resistance assume a resistance of say
0.05 ohms the maths tell me Volts divide by Ohms = 240amps. Since the power source is a small battery of limited cranking current and a british motor (very close motor tolerances) at a cold start the motor
would be somewhat tight to turn over initially. Long stroke and at different points of the stroke cycle at start would vary initial cranking torque required.
The results are inconclusive, but satisfy me in my mind that the bike still starts, the load on the
battery is enormous to pull it down to 7v(this occurs for a very brief time eg.milliseconds) as the motor starts the current falls and the voltage will rise (voltage is inversely proportional to amps when the circuit resistance/impedance is constant)

LIMITATIONS OF TEST: short but tells me a story of what the battery is doing, it would be nice to log the DC amps and have a digital trace oscilloscope with memory to trace the voltage, but this was just a quick look. Also to log the voltage after each interlock and ECU output to see who stops the start.

Conclusion: the testing proves my battery is ok, the cause of the problem is unresolved. The probability of it being the choke is false as it only affects motor idle rpm and A/F ratio.
The clutch/neutral/stand switches are only start interlocks.(new bike their fine). The ECU being microprocessor based would have a 3 or 5v supply rail from a DC to DC convertor with filtering, as the min volts stayed above 7v a 3 or 5v rail would not be compromised. As no one but TRIUMPH has the source code to the ECU we have no way to decifer the program logic behind the controls.
The only conclusion may be is that the duration of sustained low voltage below a preset voltage will trigger a ECU start abort. As pre-empted by others on this forum.

HOW DO I FIX THIS: Triumph wont, but in the back ground may change this threshold on future models.
A bigger battery will uphold the voltage better with high cranking current.
Fit a kick starter? but they put a electric starter on it because 865cc is just hard work to kick over
- could be why a small starter motor with a small limited battery sometimes just struggles to do its job.
Me, I think I'll put up with it for now until it becomes a real bitch!

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it ain't over till the fat lady sings, but sometimes she just wont sing!

Captain Bert

For you other guys out there with serious start issues, start with this concept - get a good battery and check the following

"Also to log the voltage after each interlock and ECU output to see who stops the start."

interlock = neutral switch, clutch lever switch and kick stand switch

mike1161

I've still been watching this thread, and THANKS Captain Bert for running this test! I guess that pretty much sums it up! It really is a voltage threshold issue, just like most of us suspected. This still happens to me, but oddly, maybe just 5% of the time now. So, I guess I'll just live with it...

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Current bikes: 1970 Suzuki T350, 2008 Triumph Daytona 675 SE
Old bikes: 1971 Honda CL350, 1982 Yamaha 550 Seca, 1986 Yamaha RD350, 1988 Suzuki RG500 Gamma, 1986 Suzuki VS700, 1975 Kawasaki Mach II (S3), 2012 Triumph Bonneville T100

jeiser

So that kind of sucks knowing the problem and not having a good solution. Perhaps a bigger battery is in my future should it come to that an even then it's not a great fix


Sent from my iPhone using Motorcycle.com Free App

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Jay

That's all the motorcycle is, a system of concepts worked out in steel. - Pirsig

Forchetto

Triumph have been looking for a quick and easy fix already. When the EFI bikes came out they fitted an even smaller battery to accomodate the ECU and a plastic wedge separator next to the battery. This became part YT12B-BS which is around 18mm narrower than the previous carbed battery, the YTX12-BS.

Following people lining up to complain about battery troubles they hastily modified something in the airbox-ECU layout and replaced the previous larger carbed model battery on the EFI bikes.

On the SE at least this took place form VIN number 463262.

What battery do you have on yours?.

jesseoff

Ideally you'd be attaching your probes to the power and ground leads on the ECU pins directly. With such high current moving through the power wires and ground wires and frame, the voltages as measured across the battery terminals can be different than the voltage measured across the starter terminals which will be different from the voltage measured inside the ECU.

Also, if the voltage does fall all the way to 7V, a lot of those 12V relays probably are loosing enough strength in their magnetic fields to cause them to release against their internal return springs and switch off.

moth

I've got the fix!!! Go back 50 years Mr Triumph, drill and tap a hole in one side of the head, fit a decomp fitting and cable/lever. (only joking)
Moth
It would take the load off though!