Bike won't start

[MattJ]

I crashed my bike about a month ago and had a bit of trouble getting a generator cover and fitting it but after I finally got that done the bike wouldn't start.

All the lights come on as they should do and when I press the starter button the engine turns over but just will not fire no matter how long I hold the button for or how wide the throttle is open. However, the bike will bump start without problem and runs absolutely fine.

I changed the spark plugs today hoping that this would sort the problem but it still won't start from the button. The old plugs weren't in a terrible condition either, 2 of them were a bit fowled but that's it.

I've no idea what the problem could be but hopefully someone on here will have an idea.

Thanks.

[_Iain_]

generator wired up propperly?
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Please be aware that the above post may be full of complete nonsense.
Riding: '07 KTM Duke II, Baotian BT49QT-20 Driving: '88 Volvo 340

[MattJ]

Yes but as far as I'm aware that wouldn't affect the starting of the bike anyway.

[P.addy]

Do you get a decent spark?

The pulse coil (think its called that) is under the left hand engine casing. They are expensive to replace...luckily mine was intact. What's the state of yours?

[ZaphodBeeble]

What bike is it? I would suggest checking the valve clearances and/or carry out a compression test.
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Current bike: VTR1000F Firestorm. Previous: Firestorm (written off) - XJ600 Divvy - NSR125 - DT125 and a load of offroaders.

[MattJ]

There's isn't anything under there, mine is the 4JH model though remember.

Haven't tested spark because it bump starts but I will test it. Brother is dropping his multimeter off soon too so I will be able to check the battery but I will be surprised if that is the problem.

[MattJ]

[ZaphodBeeble]

It WOULD affect it but you wouldn't notice. It would be a loss of power which had developed over years of riding. If all else fails with the electrics then I highly recommend checking it.

Did the bike lose any oil when you stripped it/crashed it?
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Current bike: VTR1000F Firestorm. Previous: Firestorm (written off) - XJ600 Divvy - NSR125 - DT125 and a load of offroaders.

[MattJ]

Not as far as I'm aware.

[bikenut]

:karma: so it starts with a bump start! but not off starter!

bump start whizzes engine over fasster than on starter motor?

is the starter whizzin the engine over fast enough fopr cdi ign system to, produce a good spark??

[Scotsman37]

Just a suggestion closely inspect your starter solonoid by removing the main fuse and check for signs of heat damage, and remove the four prong connector that plugs into it and give them a thorough clean. If there is signs of heat damage to the fuse and/or solonoid replace it, as there is now a wide enough gap where the fuse fits to cause an eletrical arc and therefore you will not get enough/ no electrical current to reach the ignition coils. It will just keep damaging the solonoid unit.

[GrumpyGuts]

+1 for solenoid.

After refitting the solenoid earth lead, the wire was touching the exhaust thus melting it and shorting the connection. I then had the same problem as you, the bike could bump start but not from the starter button. Every time I tried to start the bike the solenoid would just make a clicking noise, the same noise it was making when my alternator was not working.

I repositioned the lead and insulated the damaged area and it fixed the problem. Starts first time
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My Bikes: Lifan Beat 125cc '11 -> Suzuki B120P '76 -> Suzuki EN 125-2A '08 -> Honda CG 125 '04 -> Honda CB600F Hornet '98 -> Kawasaki ZZR 600 '99 -> Kawasaki GPZ 500S '95 (Current)
Theory test passed - 09/02/2012 >>>> Module 1 passed 24/07/2012 >>>> Module 2 passed 24/10/2012

[MattJ]

It's not the solenoid. As I said the engine cranks over but doesn't fire up.

Could it be anything to do with the stator, as it is a little bit damaged but it's only taken a little bit of the plastic coating off it.

[Triumph1300]

Could be battery, could be other things, it's almost certainly electrical.

Check the spark whilst cranking, also put your multimeter on the battery whilst cranking, and see what the voltage drops to.

Some CDI's don't like working much below 9/10 volts.

Report back, and we'll go from there
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BWJ
Back on a BMW R80RT
Punctuation - the difference between knowing your shit, and knowing you're shit

[ZaphodBeeble]

Ahh wait a minute. I had a similar problem with a CBR400 NC29. The timing pickup was very slightly too far away from the metal bit that it picks up from after the bike was dropped. Check the gap on the pickup and adjust the gap as tight as possible. I'd put money on it being this.

A bit more info; I believe this happens because the timing pickup is probably a 2 wire reluctor type sensor which requires a piece of ferrous metal to be passed across it for it to produce a current. If the metal is too far away and moving slowly (ie. when using the starter motor) then only a relatively small current will be produced. However, when you bump start it the metal moves at a higher velocity and induces a higher current in the pickup. By moving the pickup closer to the metal it should produce the higher current that the CDI needs to be able to detect a timing signal.

Later machines have a 3 wire 'hall effect' type pickup which is powered by two of the wires (positive and ground) and outputs either an off or on signal on the third wire. They are generally more accurate and reliable.
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Current bike: VTR1000F Firestorm. Previous: Firestorm (written off) - XJ600 Divvy - NSR125 - DT125 and a load of offroaders.

[MattJ]

[ZaphodBeeble]

No problem. Glad I could help.
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Current bike: VTR1000F Firestorm. Previous: Firestorm (written off) - XJ600 Divvy - NSR125 - DT125 and a load of offroaders.

[kotachi]

Awesome shout sir
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CBT done - 24/03/2012, theory test done - 03/04/2012.. Mod 1 done -26/06/2012, Mod 2 done - 29/06/2012. Current steed: Cage.
Suntan Sid said: "Look at it this way, your employer wants to pay you the minimum amount, it thinks it can get away with, and extract from you the maximum amount of graft. Ergo it's your responsibility to ensure that karma is restored and you do as little work as you think you can get away with, for the maximum amount of money."

[Walloper]

[ZaphodBeeble]

I'm off the booze at the moment so that doesn't leave much of a choice...
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Current bike: VTR1000F Firestorm. Previous: Firestorm (written off) - XJ600 Divvy - NSR125 - DT125 and a load of offroaders.

[MattJ]