OK  many of you have read on the possessed bike I'm working on... basically the left cylinder wont fire!  Here's a link to it cause it would take all day to list what I've done to try to fix the problem again!  http://gstwins.com/gsboard/index.php?topic=25925.0 

I have few additional ideas i'd like your collective thoughts on. 

1.  Could tight intake valves cause my problem?  I know my intake valves are too tight (couldn't fit my .04 feeler in).  My exhuast valves are loose but only by a very little bit.

2.  I checked the compression for the bike.  My understanding (as my buddy has my clymer at the moment) is that after warming the bike up (which is harder to do when your left cylinder wont fire at all) the "normal range" of compression is 144-199psi.  The minimum allowed compression is like 114psi. 

When I checked the compression "cold" on my bike  the left (bad) cylinder was like 126 and the right (good cylinder) was like 135.  I warmed the bike for like 5-7 minutes as best as possible on only the right cylinder and got a  reading of 119  on the left cylinder (the bad one) and 130 on the right (the good one). 

My thinking would say that for a cylinder to just plain not fire it would have to be REALLY REALLY low compression like 60-80psi.  I could understand a loss of power with 119 but for it not to fire doesn't seem right.

I say all this because I recently rebuilt my head.  Thinking I might have sealed up compression up top it could have shown deteriorating compression on the bottom that became exposed once new oil seals and tighter (newer) valves were installed.

3.  I'm a retarrd... I didn't "lap" my valves when I installed them.  It didn't show wiggle room and I was in a hurry ( i know... I'm stupid).  Could this cause oil to leak and thsu not allow my left cylinder to fire?  My plugs are super black (or they were when i COULD get it to fire some) and a hard sheet of it when its plugs would foul. 

I was hoping the compression would say super low so i could put new rings on and relap the valves and move on... does anyone thing one of these three options could be the culperate (rings, valves, valve shims too tight???)  Does anyone else have more ideas?

4.  DOES ANYONE HAVE A GOOD WIRING HARNESS... MY ONLY IDEA IS THAT I NEED A NEW ONE...

The valves could be an issue.  If they're too tight, you should probably fix that.  But you had this problem before you did anything with the head, so I doubt that is the problem.

Your compression sounds fine... you are correct, if there was something wrong it would be much lower.

I still say it's your wiring harness.  Have you checked it over?  A damaged wire harness is super easy to fix, I don't see any reason why you would need to replace it unless your bike was in a horrible fire or something.  Seriously man, if you haven't already, you need to sit down and take your time and check every wire and every connection with a multimeter.  Hell, you can send me your wire harness and I will check it for you.   

I'm looking at the harness today... its all ripped apart so i can now...

The problem, however... never existed untill i bent the valves (replaced head gasket and then set the timing wrong) and then rebuilt the head.  It ran fine prior to the rebuild.  While awaiting the rebuild, however, it did sit outside all winter!  But as soon as I fired it up post rebuild it ran as it runs now... just writing this is pointing me closer to the head/valves/clearance/ something there... hmmmmmm...... what do you guys think

oooo... OOOOOO... I didn't know that... in that case definately take a closer look at you head

but because it does sound like you have decent compression, still check out your wiring harness and consider it suspect

when looking at the head... woudl you find the shims to be more suspect or the valve seats because i didn't laP

Super black plug on the left side you say?
Perhaps you have a pinhole in the diaphragm in the fuel petcock.
This allows petrol to be sucked down the vacum line and into the left cylinder making it super rich.

To test for this I recommend fitting a transparent vacum hose, or at least taking the current
one off and seeing if there has been fuel in it.

I would suspect both... but I would suspect them in order of ease to repair... after you check out your wiring harness and are sure it is ok, fix the valve clearence issue.  Last I woud lap the valves.  I don't know about the GS's engine, but I've heard of people not lapping their new valves on other engines without a problem. 

Phil brings up a good point, and it is worth looking into.  Another option would be to plug the vacuum line from the carb and setting the petcock to prime and see if that makes a difference. 

I know this sounds dumb... but the previous owner removed the petcock.  This has never caused a problem in the past... it was like that since I've owned the bike.  The petcock was replaced by a plastic "Y" pipe that connects both outlets from the tank into one hose!  Could the valve clearance cause this?

Please??? More input???

Quote from: KYGS500E on May 02, 2006, 05:01:11 AM
Please??? More input???

What about some output? Look, you get tons of helpful hints what to check. Never a word from you what you checked and what those checks turned out. We ain't no telepaths. Some feedback is in order before you ask for more. The trouble shooting cycle is a loop.

bad day??? Geez!!!

I'll post up some more on the findings of my tests tonight

have you checked for spark?  also reseat the ignition module and see if there is any change.  it worked for me. the battery juices caused surface corrosion on the connections.
also happens when the bike gets wet.

Good luck.