2007 TRIUMPH SPEED TRIPLE
Q:I’m writing on behalf of my partner who rides a 57 plate Triumph Street Triple. She has been suffering with an issue for quite a while that we have not been able to resolve. Despite trying to research this online on various forums I have not found any definitive answers as to how to get it fixed, the issue being the bike will fire up no worries and will ride fine until it gets up to normal running temperature and needs to be restarted after, say, refuelling /stalling, etc. It acts as if the battery is flat and just does not have the power to turn over. We are forced to wait around 20 minutes for it to cool down again and it will once again start with no issues. I can confirm that the regulator/rectifier, stator have both been replaced with Triumph parts (both had previously failed). The bike then sustained some minor damage in an accident, resulting in no more than cosmetic damage (sadly the rider took the impact of bike on her). The starter button assembly has been cleaned, as has the main earth wire; the starter solenoid was checked and the battery has been replaced with a Motobatt. A second-hand starter motor has also been fitted, but all this has not helped and is really adding up the pounds. We are both losing faith in what is in every other way an excellent bike so any ideas will be gratefully received, as all I can think of left to do is a full diagnostic check to see if this will show anything.
A:This is interesting because one would normally expect the reverse situation: the engine starts ok when it is hot, but not when it is cold. Firstly, let me get one point out of the way. Over the years I have come across lots of similar situations and the advice given to the owner is something like checking the ignition system, carburettor settings or fuel-injection system sensors, but the respondents have missed the point. Your issue is not just that the engine won’t start –it won’t even turn over properly, so of course it will not start.
Normally, the situation is that the extra load provided by cold, viscous oil combined with a less efficiently working battery means that the starter motor struggles to cope. It should have an easier job when the engine is hot, so what could be the problem here?
One thing that could make the hot engine hard to turn over is that it has partially seized, but then it is ok when it is running. Another possibility is that there is a fault with the ignition timing, such that it is too far advanced, but only at low engine speeds when hot. I suggest to you that both these possibilities are highly unlikely! Much more feasible is an electrical fault. What it boils down to is making sure that enough electricity is available to be used, and ensuring that it can reach the starter motor and return unimpeded to the battery. So next time you have the hot engine running, check the voltage across the battery terminals. It should be around 14.5 to 15 volts. Then stop the engine and after five minutes or so, check again. It should now be around 13.2 volts. Now, assuming that the starter is not working properly, check the voltage
when you press the start button. It should be no lower than 9.5 volts. If it does drop too low, either the battery is knackered or there is a mechanical problem in the starter or its drive to the engine. Next, as you press the button, check the voltage between the battery +ve terminal and the starter motor terminal, then between the battery casing and the battery -ve terminal. The voltage drop (which is what you are measuring) for either should be minimal: no more than a fraction of a volt. If either reading is higher, there is a problem with an electrical connection or perhaps the starter relay on the +ve side. This could be caused by the heat from the engine, such that it is ok when cold, but not when hot.