Have you tried jumping the starter motor itself? Put the bike on the center stand, take off the starter motor cover, and pull back the little rubber boot on the wire. That's where the positive lead is. And to make the motor spin easier for testing purposes, remove the sparkplugs from the bike (don't unscrew them and leave them dangling in the plug wires). Leave the ignition switch off and use a jumper cable on the starter. You should hear any noises very easily this way.

Quote from: Big Rich on March 13, 2011, 06:32:47 PM
Have you tried jumping the starter motor itself?

I haven't tried pretty much anything yet. But it sounds like a good idea. As soon as I have some spare time, which will be this Saturday, the earliest, I will try what you mentioned.

I was just working out in my garage and decided to see if bike starts normally. It did. No issues at all. It fired up at second or third turn of the motor.
There were no noises or anything unusual.

The problem seems to be totally inconsistent. Once is starts perfectly, the other time it barely turns over or produces this metallic noise. Weather, temperature, humidity seem to have NOTHING to do with it (at first I thought the problem was with cold temperature starting but apparently is not as it is not cold anymore)

if you have any other ideas I am all ears!

Quote from: kml.krk on March 13, 2011, 04:27:02 PM

Quote from: mister on March 13, 2011, 11:32:15 AM
BTW, being Hard to push the bike while it is in gear is Normal for the GS. No need to start chasing your tail trying to fix that as well.

Quick question... how many wires are you reconnecting on each side of the battery - got a photo of the connection even?

Michael

I am not quite sure if I get your question. How many wires are there? 
I thought there are two, one connects to + and the other to - on the battery...

TWO wires to the negative...



Michael

I will check but unless the wire snapped it should be just the ways it was from the factory.
I didn't touch or modify those wires.

Thanks for clarifying that for me.

BTW: I cleaned the connections to the battery yesterday. Bike started quite OK this morning (no noises but a tiny bit of hesitation from starter, which sounds like it is spinning OK, then backs off and spins again)
I wish I had more time in the mornings so I could record the video with sounds of my bike starting.

Would it be helpful? If you say that it definitely would help then maybe I will wake up 30 mins earlier and do it.

UPDATE: bike hesitated to start after school. Fortunately battery provided enough juice for lots of cranking.
On first try bike did not want to fire up (it turned over fine about 6-8 times)
It's interesting that it didn't start after so many turns 

After about 30 seconds I tried again and on 2nd or 3rd turn it produced this stupid metallic sound then about two more turns and it finally started.

I don't even have time to properly troubleshoot it. All I can do at this point is to read your comments and hope for some enlightening...

hey, it's me again:
I recorded a sound of the starting noise!

put the headphones on to get more accurate sound (the recording is done with cell phone sitting on the tank)
http://www.youtube.com/watch?v=I0VnZ7k99mY

All suggestions are greatly appreciated.

Sounds more like a backfire than a mechanical clunk...not sure...maybe someone else will have a better idea...

Sounded like my GS when the battery was shagged in it. New battery and all was good.

i am not sure about your problem but i had some battery issues in past years and in your case, i would change battery... i think this battery is very weak... my last battery story---i charged it all night with optimate4 charger, fully charged diagnosis, then started the bike and had no power to start the engine more than one time...---

then i put an on/off light switch and a yusa yb4l-b(4ah) from my honda cub into gs... i run the bike in position light with day light and guess--no missfiring... excellent. BUT for SAFETY reasons, we need to have headlight ON ALWAYS-- i do not suggest this... i also know that the 4ah battery will became useless very soon--i have that battery on  bike for about 10 days---it's some kind of experiment... i will let you know how many days this battery was ok before become useless.

I bought new battery on December 4th, GEL type because I wanted more cold cranking amps for cold day.
Worked fine but died (it's going back) today, and I will get replacement in couple of weeks

I put in my old battery which was OK, and still is OK. I load tested it. It holds charge well and cranks fine during repeated tries to fire up the engine.
I am 99.9% sure it's not a battery, and I refuse to spend another 50-70 bucks on a new one.


Yesterday I let my father listen to the sound (recording, not the real thing) and he thinks it MAY be sticking valve.

I hope nothing blows up until Saturday, and then I will do investigation.

Do YOU think it may be sticking valve, and the noise that is produced is by piston hitting a valve? I am not sure how GS engine looks internally but I looked at other engines and technically it is possible.
Let me know please!

As far as I know, the GS engine is a non-interference engine...but I could be wrong...if it was a sticking valve though, you would probably have a very evil running engine...and once it starts all is good, right?  I wonder if it is something as simple as a start button that isn't making good contact?  Check your connections to the switch...for some reason I'm thinking bad connection somewhere...

Later.

I cant see the video from work, but the intermittent nature and not starting both put together can more than likely be caused by an intake or exhaust leak.
Check for those.
Cool.
Buddha.

Quote from: kml.krk on March 12, 2011, 12:11:01 PM
What I am worried about is this noise that is present more and more often, but ONLY during starting.

It sounds like two hammers smacked into each other.
I've had weak battery issues before (due to short commute), but this noise is new to me and it worries me.

I'm almost positive that it's the starter motor. I've had this noise too while my battery was weak. My bike barely turned over, barely turned over, then BANG.

I found out that my problem was that I wasn't riding it for long enough haha

ME?

I would push start it.....

Could be:
Missing, broken, worn teeth on starter or flywheel.
Low battery (easiest to change out).
Bad starting relay.
Bad starter.
Broken, loose, frayed, corroded, damaged, dirty, unkempt, yucky, painted wire connection...
Bent, broken rod.
Bent, broken, damaged anything else internal engine pieces.
Compression check?
Dirty spark plug(s).
Bad gas.
Bad plug wire.
Bad ignition.
Freaking cold out.
It's a mechanical contraption, therefore it was designed to break.

(check the voltage across battery while starting it, if it falls below 12 volts i would change the battery after checking all wire connections)

But.... ME, i would push start it, and go from there.

Oh my. I am not sure what to do next to diagnose this properly. I will receive new battery in couple of weeks.

Bike runs perfectly after it starts and starting is not a regular issue. Sometimes it occurs sometimes it starts normally. Today it started fine 5 times. 4 out of those were with warm motor

hey guys I am working on the bike now.

It appears that the gasoline is ignited too early. Like the timing was messed up, but how could that be?
What else may cause premature ignition??
Could 2 different gas stations be selling gasoline that is advertised as 87 octanes but in reality is lower? This could cause premature ignition.

I need your help fast, bike is still in pieces at this point.


PS. Valves have good clearance, starter motor is fine, solenoid works fine. Bike has only 5000 miles on it.

How do you know it's pre-ignition? Just curious.

Since the timing is ultimately set by the crank sensor on the right side, I would check that first. Maybe a loose wire or something? Doubt it though. Could be your cam chain tensioner is loose and the cam chain slipped a tooth, but that's also unlikely.

Quote from: Big Rich on March 19, 2011, 05:02:03 PM
How do you know it's pre-ignition? Just curious.

Well, there is this loud noise, and after hearing it many times, analyzing, researching, my dad and I came to this conclusion.
It sounds like explosion followed by a metallic sound, and it happens only when starting. Engine almost turns over, then pretty much stops and... BANG, and you can see carburetors moving!!! I can properly describe it but there definitely is internal explosion and gases are released through carbs.

That's why I think it's pre ignition, because if it ignited in the right moment, it wouldn't spin backwards and exhaust through carbs.


I noticed very unusual thing which actually remedies the problem: do not use choke during start up.
I tried starting on very low battery today, and if I used choke it would not turn over and would bang a lot, but then I tried with no choke and it turned over just fine, even with very low battery, and didn't bang/backfire or anything like that

I also noticed that when starting using booster (jump starter) it didn't bang either with coke or with no choke.

So why does it turn over easily and start when I don't use choke and doesn't even turn over when I use choke? (remember that today's test were done without recharging my battery which was quite low towards the end of the day [11.8V])
I can make a video if you don't believe me. My father said that he's been working with cars for past 35 years and have never seen such phenomenon.... (he's auto body man, but he know a lot about mechanics and engines too!)

I think the noise you're describing is just back firing out of the carb. Generally caused by a lean condition but the choke part doesn't make sense.....I see you rejetted, but what about the mixture screws? And maybe your choke cable needs adjusted a little- it may literary be starving the engine for air.

Fwiw, I'm not doubting you or your dad.

Mine made that metalic clang sound today when I was trying to start it for the first time this year...battery was almost flat, and the starter partially disengaged while trying to start the bike...that is the sound you are hearing...try boosting it from a stronger 12V battery and I bet you don't get the clang...I forgot to put the battery on charge last night before trying to start it today, so I thought I would just give it a shot...result...battery is now charging for another attempt tomorrow....

Later.