Bike struggles to turn over from cold sometimes

[nathaniel2910]

Hey guys I know my bikes not starting threads are everywhere but I can't find any that relate to what's wrong with my bike,
I've had the bike on the road for 2 months now, it's a 03 plate.
Anyway when I got the bike the battery was toast so I replaced it with same battery stock gs one.
Anyway after the first week of riding it started getting cold out and I found the bike would be slow to turn over, I put this down to the battery getting flat so I charged it, it was fine for another week and started again, I put this down to the 0.5amp trickle charger coming to the end of it's life as it did a similar thing with a sealed gel battery on a 125 bike I have.
I purchased a oxford oximiser charger and charged the gs battery over night so it was definatly fully charged.
Bike started fine but coming home it wouldn't start, it was just cranking really slowly, I tried bumping it with a friend pushing me but we couldn't quite get the speed.
I did try the start for a few seconds at a time to warm the battery up but that didn't help, after 5 mins of slow stop start cranking it fired up and ran fine.
The fact that I was able to crank repeatedly for 5 mins shows the battery was fully charged,
I'm just unsure why it's doing this.
Also when it does this if I use full choke after a min or two it will backfire, so I have to start with no choke then turn choke on full, I'm unsure if that's actually a issue as when it cranks at a normal speed it will fire straight up with full choke on.

Valve clearances were checked and adjusted 300 ish miles ago, the only serviceable things that haven't been changed so far are the air filter and the plugs as they appeared to be relatively new( no wear at all).

All the wiring appears to be intact but I will go over everything and check all the connections,
It's just strange that it mimics a low battery with the very slow cranking but if the engine isn't completely stone cold it will start fine, it seems to be more of a intermittent problem.

Have any of you guys come across a similar problem and found the cause, other than the wiring the starter solenoid and connections is there anything else I should check, I'm hoping it's not the starter itself that's the problem.
Thank you in advance for any reply and I apologise for my rambling.

[fetor56]

Probably not related buy a good idea anyway to confirm correct plugs if NGK(DPR8EA-9) and check plug gap,0.9 mm (.036")
As i'v never been a fan of wet batteries i'd look also at that.

[adidasguy]

If the bike turns over, it is not the starter motor.

5 minutes of steady cranking is not good for the battery or the starter.

Do a start - wait - start - wait. 5-10 seconds of start. Wait 10 seconds or so to let the battery warm up. Repeat.

Tight valves can make cold starting hard. When cold, the valves are even tighter because the aluminum shrinks. When I loosened upthevalves on Suzi, she totally changed how fast she starts.

[Kiwingenuity]

I would suggest checking your rectifier - it is possible that it could be the culprit.. otherwise check your connections for moisture / condensation - it is possible something hasn't quite been plugged back in correctly in the past.

Plugs are worth changing when checking the harness - one less piece of the puzzle...

Adidasguy is correct - Definately not good for the battery or starter motor to crank that long - and may cause damage to both parts due to the high currents involved in starting.

There is a link to good testing methods (posted by GSJack) here:
http://gstwins.com/gsboard/index.php?topic=58537.20

Be interested to know if you find the cause - good luck 

[adidasguy]

Kiwi correct to check the charging. Get out your volt meter and give it a look see.

[gsJack]

Check the air cleaner first, I had the same problem with my 02 GS.  Very dirty air filter caused it to flood when it's was cold out and choke was on.  Would start to fire without choke but wouldn't keep running without it.  Dirty filter raises vacuum in carb while cranking and sucks in more gas.  That was a couple years ago and it did it again recently on a cold morning and I put a jumper on it and it fired right up.

[nathaniel2910]

Cheers for the replys,
I didn't crank non stop for 5 mins it was stop start cranking, so exactly as you stated Adidas guy roughly 5 seconds cranking and waiting at least 10 seconds before repeating, wouldn't want to over heat the starter.
Fetor56 The plugs are the correct code dpr8ea9, I think I set the plug gap to 0.8mm, will pull them and regap them.
Kiwingenuity cheers for the link will do that tomorrow.
Gs jack the airfilter is rather filthy but it wouldn't affect the rate the engine turns over, when it spins fast enough it fires straight away it's the starter just isn't spinning the engine fast enough.
I would say it spins maby 10-15 revolutions over 10 seconds it's that slow.
Again cheers for all your imput guys it's greatly appreciated hoping to have some answers tomorrow

[gsJack]

I've been riding year around here in NE Ohio for 30 winters in temps down to 20F on 4 Honda and 2 GS500 bikes and all were somewhat hard to start in the winter and needed jumped a time or three every winter.  Keep in mind there may be several things contributing to your problem, if you find only one problem that fixes it lucky you.   

One of the bikes was a CM400 twin that was the only one that had a kick starter.  I could grind it down until it just growled and then give it one kick and it started.  Same with my GSs, crank them down and then a jump from a car battery fired them up immediately.  Good examples of how much cold heavy oil takes so much of the battery that there is not enough voltage left to fire the spark.

If the air filter is dirty replace it, might not cure the problem but will help.  If you have not put in new plugs in since you've had the bike do so.  Plugs will stop firing at lower and lower compression pressures as they get older, we used to test them before labor became more costly than parts, now it's just R&R them.

No mention of what oil you have in the bike, if it's 10W-40 or 15W-40 it's OK but if it's the 20W-50 some use in older bikes in the summer it will greatly reduce the cranking speed when it gets cold out.  Also check your plug wires, they are screwed into the coils and bonded in place and you can't turn them if they are OK, if you can turn them a bad connection could be part of your problem.  Spark takes path of least resistance.

Ran my 02 GS on 15W-40 oil for it's first 100k miles and then put in 20W-50 late last summer because the jugs were starting to rattle and that made it sound better but was still in there the other day and it cranked about half speed when it was about 40F out and I jumped it.  No big problem since I got a jumper unit, if I was commuting to work where the bike sat out in the cold all day I'd carry it with me, long retired now.

http://www.batterychargers.com/ProductDetail.aspx?ProductName=94026903

By the way, I switched to AGM sealed batteries about 4 years ago and have been starting in the cold much easier now.

[Blueknyt]

this is gonna sound funny, specialy comeing from a south florida boy.  but many years back we had a cold weather snap come all the way down and it was in the low 30's for a week. it was cold enough to stick the windshield wipers to the windshield with frost.  my daily transpo was the GS500 and a yamaha xj650.  both batteries were good, but engines jetted and tuned but they would not crank for nothing and had to pushstart (yeaah thats fun at 5am by yourself) what i discovered by accident , i lubed up the chain on the GS one of those evenings and was using a 60W incandecant in my drop light under the bike and left it on over night. the heat from the bulb kept the oil and engine warm to the touch and enough heat filtered past the battery to make it... well....not cold.  the next morning i put the key in, and it fired right up, needed almost no choke and down the road i went. coming home in afternoon wasnt as bad to start as overnight.  so now every time it gets below 40 (rare thing this far south) i put an old 60w bulb under the engine and toss a cover over the tank draping around the sides of the engine.   works like a charm.   i guess one could call that the poormans improvised block heater

[78530i]

I ride mine in CT when the roads are not too slippery. In the winter, my lithium ion battery wont turn the motor unless I heat it up by trying to start a few times and giving it a minute to react. Nobody ever believes it is going to work because its sounds dead as hell when I first try to start. Like... "How is the battery going to charge itself?"

[sledge]

when it spins fast enough it fires straight away it's the starter just isn't spinning the engine fast enough. I would say it spins maby 10-15 revolutions over 10 seconds it's that slow.

Bad electrical connection or ground somewhere?
Worn or sticking motor brushes?
Worn bush in motor?
Armature winding breaking down to ground under load?
Starter clutch slipping?

.....but before anything else I would get the battery load tested.

[Erika]

I switched to an agm sealed battery and noticed better cold cranking performance. I've also heard good things about gel cell batteries. Like the guys said, check the connections/plug gaps/air filter. Also, this may sound weird, but check your tail pipe. I had a friend who had similar intermittent cold starting issues. He couldn't figure it out until one day a startled chipmunk shot out of tail pipe. The little guy was storing nuts in there. Critter issues tend to happen when the weather gets colder.