Wont start

[ericeek]

I have a '91 GS500 that was brought to me to work on. After draining the puke smelly gas, cleaning carbs.... i tried to set valves, both intake valves are so far out of specs even the shim chart in the manual wont go high enough for proper shim. It only has 5 K on it and was sitting for some time, removing carbs(again) I looked in the intake area and can see large amounts of "pre-mordial" type ooze all over the backsides of the valves. Ive confirmed that the cam is in the correct position and have taken flashlight to spark plug hole and can also confirm that valve is not seating closed and i have a very large gap between the shim and cam. I try to start the bike ( with  carbs and assorted things back on) but all I get is extreme back pressure through carbs. A comp. tester reveals almost no comp. so.... Do i have to take head off and get he ooze off the intake valves?  ive never seen this before. and i was hoping to fire it up and maybe burn off this ooze.   

[Roadstergal]

You're saying the valves are so clogged with gunk that they won't close?  I'm not surprised it won't start.  Are you sure they aren't bent?

[ericeek]

I dont think the valves are bent due to the fact that I have seen this bike running about a year ago and I even drove it around the block once. Perhaps a year and a half, I don't recall the mileage at that time but I'm going to guess it wasn't much less than it is now. I was just hoping that I didn't have to take the head off. This was supposed to be a simple tune-up and just sort of go through things to make sure everything is fresh and serviceable. Once I discovered this gooey muck, I  tried to scrape, pick,dissolve, blow-out and I still come up with an unacceptable valve clearance. SO..... bent valves? Perhaps, but how do they get bent from sitting? Stuck valves from gassy/oil varnish muck.....perhaps, but then how did all that gassy mucky ooze get there?Any suggestions?  

[the mole]

Sounds like the valves are being held off the seats by all that gunk. Definately do NOT try to reset the clearances until they are all cleaned up and its been running. If you can't dissolve/scrape it off in situ then you'll have to pull the head. Never seen anything like that before! If it was running OK and has only been sitting, then the valve clearances can't change and the valves can't get bent. Are you sure noone has messed with it?

[ericeek]

I'm pretty sure nobody has messed around with it, I just can't believe what I,m coming up with. I have never seen or heard of this type of concern, and I have got some really old turds up and running without this kind of hassle. Guess the head has to come off and get the intake valves out so that area can be properly cleaned out.......dang!

[Paulcet]

I am certainly no expert, but I would try some kind of solvent, knowing it will get past the rings and in to the case.  So drain and replace oil before starting.

[ericeek]

Yes, I drained the oil out and left the plug out and every morning and afternoon for a week i would spray a concotion of juices into the intake manifolds in hopes to break down the goo. when i blow compressed air through the spark plug hole i get smallish chunks/crumbs but nothing of substantial size. i even rotated engine till cam has valve all the way down and try to dislodge what i can, blow it out, etc, then rotate it till it should be closed and dang it.......when i put a flashlight in the sparkplug hole i can see light from the intake side. i even put it back together temporarily and put jumper cables on it from car and cranked it but no-go. i sprayed a little carb-brake cleaner in the throat of carbs and hit starter button all i got was a few pops a loud bang(backfire knocking loosely attached carbs off) and i knew i was experiencing getting nowhere fast. i did notice thick white smoke sometimes making its way out the end of tail pipe after these backfires. when i do get this running it should be quite the show for smoking out the pipe!