Trident expires, no spark

[Gibsart]

What a pain.... just got my Trident back on the road for the weekend after fixing up the suspension and changing the alternator amongst other things. The bike was running beautifully for about 25 miles when it started misfiring and loosing power. After leaving the bike standing for a couple of hours it refused to start, checked fuel and all seemed fine, plenty of power in the battery and engine spinning over but no spark at the plugs or power to the coils apparently. I'm suspecting the CDI unit is the problem but am stumped to be honest. Any suggestions would be appreciated. Cheers, Gib

[Gibsart]

Ordered a new ignition sensor today, seems like the best place to start and least expensive if it works, fingers crossed.

[N5XL]

Gib,

Was your old alternator bad that you had to replace it? A couple of things to check while you're waiting:

Make sure the battery is fully charged as a weak battery wont start these beasts. Battery voltage should be around 12.5v to have enough voltage to start things off. If you've tried to start the engine several times with no success, you'll surely need to charge the battery by now even if it wasnt the cause of the original problem.

If you have access to a hand held meter, check for battery voltage at each coil with the key switch on. The red wire from your meter to either of the two coil connections (preferably the red one), the black wire from your meter directly to the earth terminal on the battery and key on. If you have no voltage at the coils with the key on, the ignition sensor isn't the problem.

You do have plenty of fresh fuel in the tank correct?

Are you taking the bike out of winter storage for the first time?

[Triplets]

And a new gasket for the timing cover?

Mine turned over, but refused to start - turned out to be the sidestand switch. Cut it's wires and reconnected the wires (so the loom thinks the stand is always up) and it fired straight up.

[DaleE]

I'm with Dave on this one: the replaced alternator might be where you want to start if the bike was running well prior to that repair. And of course his question about fuel is always worth asking, if obvious. Frankly, this does sound like it could be a fuel issue to me. You say "no spark at the plugs...apparently." Does this mean that you're guessing that there's no spark, or that there's definitely no spark? If it's the first, you probably want to find out for sure, because everything depends on that bit of info.

Sorry, Triplets, but I kind of doubt that your solution will help here, in that it ignores one of the key diagnostic details: the bike was running when it started misfiring and losing power. I don't think that a faulty sidestand switch would lead to that situation.

Good luck with this. Let us know how it turns out.

[Gibsart]

Thanks for the suggestions fellas, just to clarify, there is definitely no spark at the plugs and by sticking my finger in the plug lead I surmised there's no power to the coils. There is plenty of fresh fuel coming through, I've recently fitted new in line filters and a new K&N air filter. The alternator I replaced with a seemingly fine used item only because the original one had got intolerably noisey, although it was working OK. The battery is good and spinning the engine over no problem but I will put on charge before I do any more trouble shooting. Got a new crank position sensor today so will be giving that a try later on today. I'm fairly sure the side stand switch is OK and am aware of it's potential problems. Anyway I'll be having another crack at it this afternoon so I'll let yo know what happens. Cheers, Gib

[N5XL]

Gib,

Did you check each cylinder for spark or just one? Also, testing the coils for power the way you tested wont tell you if the coils are getting voltage nor will it tell you if the coils are getting the proper signal to fire from the igniter. Its a bit tricky to determine if you have spark from casual observation without taking some precautions first.

Your initial problem sounds like it spark related to me, but its no guarantee that its the problem or the only problem and its way too early to tell just yet...which is why its important to absolutely determine you have spark on all three cylinders as a first step. I personally would not change out the ignition sensor until we can properly assess the situation.

You would benefit greatly by borrowing or purchasing a hand held meter that can read resistance to less than one ohm and has the ability to check for battery voltage. Both of these functions will be required to test and troubleshoot your motorcycle properly and will greatly assist you in the future with troubleshooting problems.

[Gibsart]

O Joy ! Fitted the new pick up today and ROAR ! my pride and joy is back to life. Thanks to everyone for the offered advice it's really appreciated. Thanks Dave for the advice, I know you're right about testing methodically, I'm pretty old school I 'spose, grew up with Lucas electrics and red Hermetite, difficult for an old dog to learn new tricks !

[Gibsart]

Just given the Trident a 15 mile blast up to the mountains and back, seems to be running fine, I am very pleased and relieved.

[gnatwest]

I had this problem last summer.

Same fix.