GN250 Won't start off button, crash starts fine.

**Latte** · 24th February 2015, 08:18

Another GN250 electrical problem =D

Had issues with the bike dying randomly (coming up to lights etc). Replaced battery and all good, had a feeling it wasn't the root cause but it was the wife's bike and "I'd get round to it".

About 6 months later it had been fine, we'd been on holiday for ~5 weeks. All the other bikes fired up 1st pop, Ginny needed a jump, no drama, took it for a spin, parked it up , good as gold.

Wife reported similar issues again, for about a week, then it gave up the ghost entirely.

Normal Case:

Bike fires up the instant you hit the starter, no choke needed ever.

Current Case:

Bike will just wind over , starter motor speed sounds good.
Crash/Bump starts fine, every time.
Can occasionally get it to start if I time it right and let off the starter button after 1-2 seconds, seems to catch after I let off the button.
Bike seems to start better if I connect a car battery directly to the starter - but still hard to start.
With the choke on it sounds like it wants to start.
Once I do manage to get it fired up it runs fine (for a GN).

what I've done so far:
Replaced Spark Plug.
Charged battery from trickle charger for a few days.
Measured voltage across battery, initally ~11.5 volts, even when bike running, after charging it and running around on it for a while, now I see it build from 13+ up to 14.9 once running (even at idle). When bike is off sits at 12v. When cranking it is low 11.

Spark seems 'ok' when testing, a little more yellow than blue though. I'm wondering if it's failing when there's load on the electrics and/or the motor.

I think the above tends to show it's not getting a good spark under starting conditions. I'm thinking the coil or cdi unit. I'm not sure if the ignition circuits use the battery or the stator/rr to run, but the charging output seems pretty good. The headlight makes a difference to the idle and charging output, but this is to be expected as one of the windings goes through the headlight?

I've done some checking around the charging circuits for bad earths etc, but not really sure what to do about the ignition circuits. If anyone has a spare CDI/Coil I can test with or some simple ways to test with a multimeter or basic tools then lets have it

**Rhys** · 24th February 2015, 19:44

Have you checked the battery is full,
battery voltage should be around 12.5-12.6 volts if fully charged. At 11.5 volts its less than 20%
When the bike is running the voltage should be around 13.8-15 volts if under or over it maybe a stuff voltage Regulator / voltage Rectifier

**Tazz** · 24th February 2015, 20:20

Battery

Originally Posted by Rhys

voltage Regulator / voltage Rectifier

or stator.

Good luck!

**FJRider** · 24th February 2015, 20:30

Originally Posted by Latte

... Another GN250 electrical problem =D

Crash starts require little or NO drain on the battery to start.

Try a jump start from a car. If it starts easily ... the battery is the issue.

But ... being a GN250 ... it's easier to replace the bike, rather than the sum total of parts (possibly) not working ...

**Latte** · 25th February 2015, 08:55

Originally Posted by Rhys

Have you checked the battery is full,
battery voltage should be around 12.5-12.6 volts if fully charged. At 11.5 volts its less than 20%
When the bike is running the voltage should be around 13.8-15 volts if under or over it maybe a stuff voltage Regulator / voltage Rectifier

Sit's around 12.3 when bike is off. Low 11's while cranking. Once I get it started it sits at around 13.3 but builds up to 14.9v after a few minutes.

Originally Posted by Tazz

Battery

or stator.

Good luck!

Thanks!

Originally Posted by FJRider

Crash starts require little or NO drain on the battery to start.

Try a jump start from a car. If it starts easily ... the battery is the issue.

But ... being a GN250 ... it's easier to replace the bike, rather than the sum total of parts (possibly) not working ...

Have tried a car battery, but not the car itself. I'll give it a whirl. I've also taken the battery out of my R1 and put that in the ginny, still hard to start. Also jumped off another bike (GSF1250a) same issues.

True on the parts. Will $1 reserve if it if not an easy fix. Wife has already bought another bike so now it's just taking up space for a track bike

.

I'll report back tomorrow. Thanks all.

**Latte** · 25th February 2015, 08:56

Is there another test for the battery/charging circuit? Even though I'm seeing good voltage when it;s running, is there a current test or similar?

**buggerit** · 25th February 2015, 09:20

Originally Posted by Latte

Is there another test for the battery/charging circuit? Even though I'm seeing good voltage when it;s running, is there a current test or similar?

How bright is the headlight?
Have you checked battery terminals, earths to chassis(loom and battery)?

**Latte** · 25th February 2015, 09:24

Originally Posted by buggerit

How bright is the headlight?
Have you checked battery terminals, earths to chassis(loom and battery)?

Generally poor, but no different to before the problems. Yeah I've checked earths and connections around the RR and Stator and Battery. Not really sure about the ignition side though.

**buggerit** · 25th February 2015, 09:26

Did it bump start ok when the battery was low?

**kiwi cowboy** · 25th February 2015, 19:27

Originally Posted by Latte

Sit's around 12.3 when bike is off. Low 11's while cranking. Once I get it started it sits at around 13.3 but builds up to 14.9v after a few minutes.

Thanks!

Have tried a car battery, but not the car itself. I'll give it a whirl. I've also taken the battery out of my R1 and put that in the ginny, still hard to start. Also jumped off another bike (GSF1250a) same issues.

True on the parts. Will $1 reserve if it if not an easy fix. Wife has already bought another bike so now it's just taking up space for a track bike

.

I'll report back tomorrow. Thanks all.

i has a solution

take the charging system out and turn the GN into THE track bike

Problem solved right there.

So what da ya think of that idea

**FJRider** · 25th February 2015, 19:52

Originally Posted by Latte

Is there another test for the battery/charging circuit? Even though I'm seeing good voltage when it;s running, is there a current test or similar?

Do a compression test ... if it's low it will be difficult to start. (with less than ideal spark voltage)

Clean both battery terminals to shiny status ... and battery lead connectors too.

How OLD is the battery ... ???

**ducatilover** · 25th February 2015, 22:40

Clean the carb and do the valve clearances

BTW, are you testing spark with it earthed to the engine or with a nice hori spark testing block (easy to make, and testing it earthed to the engine doesn't mean shit)

**Latte** · 26th February 2015, 08:30

Originally Posted by kiwi cowboy

i has a solution

take the charging system out and turn the GN into THE track bike

Problem solved right there.

So what da ya think of that idea

Probably a smart idea , but my large ego and small willy won't allow it.

**Latte** · 26th February 2015, 08:35

So I tried it jumped off a car, same problem. I can get it to fire semi regularly off the starter button now, but it I need to "guess" when to let off the starter button after 1-2 seconds and it will catch. What I do notice is when I have got it started it will bog and die if I blip the throttle, untill it's been running for 20-30 seconds.

Never tried bump starting it with thew low battery.

Originally Posted by FJRider

Do a compression test ... if it's low it will be difficult to start. (with less than ideal spark voltage)

Clean both battery terminals to shiny status ... and battery lead connectors too.

How OLD is the battery ... ???

About 6 months on the battery. Will do a comp test. It does lock the back wheel if I bump it in 2nd, have to use 3rd, I assumed that meant reasonable compression at least.

Originally Posted by ducatilover

Clean the carb and do the valve clearances

BTW, are you testing spark with it earthed to the engine or with a nice hori spark testing block (easy to make, and testing it earthed to the engine doesn't mean shit)

Just against the head, yeah thats what I figured it wasnt a real test. Clean the carb it is , sigh (hate that job).

Sooooooo, anyone have a comp tester I can borrow, and a link to this Hori DIY spark tester.

**Tazz** · 26th February 2015, 10:32

Originally Posted by Latte

What I do notice is when I have got it started it will bog and die if I blip the throttle, untill it's been running for 20-30 seconds.

Has it always done that? Both my bikes are the same if they've slept the night outside.

Your batt is quite new and it is crash starting alright so personally I'd be checking and crossing off all your electrical stuff first. I got a bungly wired stator which was giving the symptoms of a blocked carb a while back. Everything but the stator was checked for a long, frustrating, time.

Just going over the wiring and making sure your earths are fine and nothing is split/damaged can save you a headache and facepalm later on.

They're common bikes. Someone might be able to lend you a reg and stator to check, otherwise you can never have too many spares