Yamaha Starting problems - Help

[Postie]

My YX 600 has reall trouble starting, if I run jumper leads from a car, it will start but after about 15 minutes of me swearing at it, and pressing the go button. I have tried the obvious (a new battery) but that did not solve anything other then the draining of a new battery. The lights don't flicker or get brighter when it revs when its going so I would presume that the rectifier is ok. Once its started and been running for 10 minutes, it will start again first pop, but not the next morning.

When i start it from cold, its winds nicely untill the battery dies then it just clicks like cricket from the solenoid.

I'm not to savy with these bikes yet so any suggestions would be great
thanks

[cowpoos]

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[Postie]

Thanks mate, very helpfull.

[frogfeaturesFZR]

Any further info ? Last service ? Replaced the plugs, coils, CDI unit ? Anything that could have a bearing on the problem.

[Postie]

It needs an oil change but that shouldn't have too much affect, its not misfiring when its going so the sparks should be ok and visually look fine.
Once its running, it runs fine as if it has no problems, its just the cold start that it won't do withoutthe help of another battery.

[cowpoos]

Thanks mate, very helpfull.

any time...... lmfao

[The Stranger:Me]

So I gather from what you say, the battery seems to be charging ok?
Like, in the morning when cold it winds over for say 5 or so minutes before it dies?

If so how are you trying to start it?

[Postie]

So I gather from what you say, the battery seems to be charging ok?
Like, in the morning when cold it winds over for say 5 or so minutes before it dies?

If so how are you trying to start it?

yeah exactly that. I press the start button, all sounds fine but it just won't fire. It gets close after a few goes but then the battery starts to die, gets a couple more turns then the battery gives the ghost all together and the solenoid starts to click. A strange thing i noticed this morning is the rev counter climbing even though its not running the engine.

The charging systems seems to be working as the battery stays charged when its running of course.

[Flyingpony]

Assuming you got fuel in the tank and not switched off.

Do you need to use the choke?

Was thinking kill switch ... but then the starter won't kick over either.

Coils?

[Postie]

Assuming you got fuel in the tank and not switched off.

Do you need to use the choke?

Was thinking kill switch ... but then the starter won't kick over either.

Coils?

fuel tank is full, it does need choke and that was on but not flooding it either. Yep, kill switch was in go mode (about the only part of the bike that was)
I am thinking of making it lightweight with help from Mr 12 gauge

[The Stranger:Me]

So how are you trying to start it?

The VFR had this problem too.

Charge seemed fine, would hot start just fine, but wind over for 5 or 10 minutes (with breaks) from cold and most of the time was very hard to start or just wouldn't from cold.

We found that if you attached a car battery it would leap into life, so we suspected the battery, say a cell had colapsed. Battery voltages seemed fine (to me) though both at rest, under load and during charge.

Not sure we ever got to the bottom of it.

We looked at all the usual suspects but the cold start technique made a huge difference.
Use choke only and no throttle from cold. If you touched the throttle at all it wouldn't start.

We later took it into Henderson Motorcycles and they tested the rectifier. Reconed there was ample charge going in, but insufficient coming out of the rectifier, not by much though. They replaced the rectifier and it was good after that. I say not sure we got to the bottom of, because there was one odd incident after that where the thing just died for several hours then came back to life, but I don't think it was related

I know the VFR have a bad rep for eating rectifiers but this one was after market and as it seemed to have sufficient charge we didn't initially look there.

[Postie]

So how are you trying to start it?

The VFR had this problem too.

Charge seemed fine, would hot start just fine, but wind over for 5 or 10 minutes (with breaks) from cold and most of the time was very hard to start or just wouldn't from cold.

We found that if you attached a car battery it would leap into life, so we suspected the battery, say a cell had colapsed. Battery voltages seemed fine (to me) though both at rest, under load and during charge.

its pretty much exactly that. If I connect it to the car bettery, it seems fine, I have tried 2 different and fully charged bike batterys with the same no go result from cold, but both were fine on the warm start up, maybe i will look around for a rectifier and see if that helps.
Thanks CaN

[Ixion]

Defective coils, or maybe CDI. Prolly the former. Maybe exacerbated by dicky starter motor/solenoid/wiring.

The coils get a bit dodgy, internally bunches of the windings fuse together. They still put out enough voltage to fire the plug, but it's lower than it should be.

When you try to start from cold, the starter load drops the battery voltage way low. And thus drops the coil input voltage, and , in turn the coil output voltage. Sparks not strong enough to ignite mixture in cold engine. Car battery works becos it's BIG. So, less voltage drop. Works OK when hot cos hot motor turns over easy, less voltage drop (and battery is warmed up too, that makes a big difference) . try cleaning all connections .

I'd say also dodgy battery cpet u say u've tried sunsitution with a known good one.

[nadroj]

try cleaning all connections.

Especially battery leads both ends, earth, coil terminals (weak voltage in = very weak voltage to plugs)

[Flyingpony]

Have you removed the spark plugs and pressed the 'go' button while holding them against the engine casing?

How big and beautiful were the sparks generated?