Electrical problems K8 GS500F

[Lifeforce99]

Hello!

I'd like to pick the selectrive brains of everyone on the forums, if i may be so bold

My bike is 2 years old and has recently developed electrical problems with the headlight; occasionally the headlight ceases to work but the pass light still works (although this i've narrowed down to being a bad earth), and the other day I noticed that my headlight pulses/flickers whilst riding, my indicators occasionally blink a little too fast and the tachometer stops working.

All my bulbs are fine, I check them daily before or during my journeys adn the battery is sound.


1 more question, quite often when I try to start the bike nothing happens except a 'click' noise from the starter relay, it can take a few attempts to start it before anything happens. Would this mean the starter relay is shagged or another problem?

Its sad really, this is the 3rd Suzuki I've owned and for a new bike its rather unreliable I had a 1980 GS450 that was better than this (although it rattled itself to bits whenever I went up the motorway).

[BaltimoreGS]

Start simple, are the battery terminals clean and tight?

-Jessie

[Lifeforce99]

Yep, over winter it got really cold so I had to charge it up a couple of times and I always clean the connections and apply a blob of vaseline or something similar to stop water/rust etc.

I think I'll have to drag a wiring schematic out and dragging the wiring about.

[JAY W]

HI have you checked your battery voltage,if its below 12.5dc it won`t crank,if you have charging issues your light will flicker bike will miss until no start.
To bypass solinoid short the two poles on top with a pair of pliers or two screwdrivers with insulated grips if cranks,new solinoid or clean connections.

[Paulcet]

Yep, over winter it got really cold so I had to charge it up a couple of times and I always clean the connections and apply a blob of vaseline or something similar to stop water/rust etc.

I think I'll have to drag a wiring schematic out and dragging the wiring about.

I would also have suggested the battery connections.  But there is more to do, starting with the connections at the fuse.  Keep going, I would bet you will find a weak connection.  And I'll beat Buddha to the punch and suggest the auxiliary ground as well.

[Lifeforce99]

I'll have to check on the battery to see if its charging, that I didn't think of!

I had it apart and it looks like some of the problems come from bad connetions in the plastic connector blocks under the front of the tank, looks like water/steam gets up there and rusts the pins in the blocks. A live wire actually fell out of a block when i moved it, makes me wonder how anything actually works at all.

With the starting issue I think I've narrowed it down to the clutch switch, if i pull it in and hammer the start button it'll click a fair few times but if i pump the clutch it starts up quicker than the latter method so i'm thinking sticky/dirty/rusted microswitch?

[Lifeforce99]

Update:

Checked the battery with a multi-meter

ignition off: 12.68v ish

engine running @ 12/1300rmp: 12.5v

engine running @ 4000rpm: 12.4v

I was always under the assumption that the battery should read 13v or something when the engine was running because it is getting charged?

admittedly the electrolyte in one cell was below the minimum mark, topped it up and have yet to test it again...

[Paulcet]

I believe that is out of spec for the voltage regulator.  in any case, you should expect slightly greater voltage at 4000 than you would get at 1300.

[Lifeforce99]

I think im gonna have to start chasing ghosts...

I replaced the battery just so I know theres no problems there, behold my bike is now in a parking lot in town with a flat battery. I've got that on charge so i can go pick it up tommorow morning. I'm gonna check the alternator and the regulator to see what they're putting out.

I've ruled out the switches, the clutch was just coincidence. Paulcet whereabouts is the auxillary ground? I have yet to get hold of a Haynes manual and a proper wiring diagram 

[Paulcet]

Paulcet whereabouts is the auxillary ground? I have yet to get hold of a Haynes manual and a proper wiring diagram 

It's the small black wire connected to the negative terminal on the battery.  Follow it and make sure it is connected securely.  Maybe even disconnect and clean it.

[werase643]

12.4v ..... you are not charging should be 13.5-14 ish V at 3500-5000rpm

[Lifeforce99]

Right.. I've put a multimeter to the alternator plugs and they all come back at around 60V ac+ @ 5000~ rpm. I have a service manual for the 1980-1999 models and they say it shoud be 75V ac so I figured thats either changed for the newer models or its on its way out?

Followed the alternator wires to the regulator/rectifier and back out to another connector block where it was putting out 12.5Vdc @5000 rpm

Just generally checked all the connectors around the battery for continuity and it all came back good.

My brain hurts 

[Lifeforce99]

Hmmm..

I haven't had a chance to strip the bike down properly, but Ive been thinking.


If there was a bad earth on the headlight/clocks/front indicators would that cause the battery to drain when it was running by semi-grounding the battery? It makes me wonder because even if the alternator is down 15VAC surely the battery would be getting a little charge put back in rather than dropping down to 12v flat?

How would I verify the alternator is dead? I took the cover off of it to look at it (got scared cos I saw oil coming out too... never opened the left crankcase on any bike till now!) and the stator  looked shiny and new, no burnt out windings, magnets were all in one piece, gearing looked sexy and nicely machined... or is it one of those things that can''t really be seen to die?

[Affschnozel]

60V isn't that bad ,to make sure check for continuity between the 3 alternator wires and for no continuity between
earth (-) and those wires, most likely your rectifier is at fault

[Lifeforce99]

I'll try that too ^^

60VAC is lower than spec according to the suzuki service manual, should be 75VAC

still, its another test to perform