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GS1000 valve seal replacement

Sandy

Sandy

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Here?s the problem. It?s 1979 GS1000 with only 18,000 (eat your heart out) original miles on it, it has sat most of it?s life covered, heated and always driven at least a couple of times a year. Now the problem is that it is now failing to fire on the #1 cylinder when cold and on the choke. After a brief warmup (30 -60 seconds) the #1 starts firing and warms up properly. Except there is bluish smoke out the left muffler for a brief period. If I turn it off before the #1 starts to fire, the plug is wet with what looks like oil (bad). All others look fine. However, once running the bike pulls like gangbusters, plug checks look great and there is no abnormal oil consumption. My theory is the #1 valve seals are hooped. By the way, until I recently replaced the center stand this bike spent all its life on the side stand so the #1 seals were probably sitting in oil for 25 years. After the long winded intro here I was wondering if anyone has tried replacing the valve seals with the motor still in the frame. I?ve seen the automotive guys do it by pulling the cams, putting an air adaptor in the spark plug hole, put the cylinder at TDC (locking the crank somehow), pumping air into the cylinder to keep the valves closed and removing the valve springs and seals. Has anyone tried this or think it will work. If I can do it this way I?ll try it soon, if not I guess the motor comes apart this winter. Any input will greatly appreciated.

PS: Have not yet done a compression check, but the bike does make great power and runs smooth so I?m not suspecting a ring problem at this time. I will have to borrow a comp tester, mine seemed to have grown legs.
 
thats funny i have a 81 gs1000g and it only has 16500 miles on it and it does the same thing when its cold it fouls plugs and smokes for a bit,then when it warms up its ok but the more i ride it the better it gets my problem is valve seals, so ride it for a while and see if they don't loosen up otherwise i would not attempt to replace them myself du to the (not real fun)timeing of the cams its not to expensive to have them replaced if you find a good reliable mechanic
 
You can't remove the valve spring keepers with the head still on the engine.

First thing; change your plugs, try a hotter plug; B7ES.

Start engine with as little choke as possible and close choke as soon as engine starts. Keep engine running with throttle only, no choke, until it warms up and then do a plug read.

A well tuned engine should stay running after only a couple of minutes of this type of warm up with a moderate ambient temperature.

I had a similar problem with my '78 GS1000E and found that while running with the choke on, I was fouling the plugs and then running like crap. The manual says you should NEVER use the throttle with the choke lever up as this will cause a poor starting condition. I think these VM carbs are prone to flooding when the choke is applied.

A little oil seepage from bad seals should not be fouling your plugs, especially if you are running a hotter plug.

You may also have a sticking needle valve on your #1 carb. I would take off the carbs and give them a good once over, just to eliminate the possibility (wouldn't hurt).
 
I'll try the hotter plug to see if that makes a difference. The bike does start easily with about 1/3 choke and will idle soon after with only partial choke and will idle on its own with no choke within a minute or two (once the #1 clears itself) of starting. I'm still concerned however with the bluish smoke from the pipe. Could this just be left over raw fuel from the #1 cylinder? I'll try as little choke as needed and see if that makes a difference.Certainly hope that is all it is. By the way, the carbs were just overhauled and new needles and seats were installed. Thanks for your input.
 
no if it was excess fuel it would be black smoke so its probobly oil but like i said run it awile and watch it closely
 
My GS has new rings, valve job, new seals, carbs rebuilt, you name it and it still puffs smoke on start up when I use lots of choke. Light bluish smoke too. No choke and no smoke. I really do think the Mikuni choke system is a culprit in fouling plugs and exhaust smoke or maybe it's just my carbs?

You may also have a cracked ring or piston. Have you done a compression check?
 
The valve seals do not sit in oil: they are under the bucket and there are big galleries to drain off the oil. The seals deteriorate due to both heat and time, so they may need changing. Our GS motors are the easiest to work on and pulling the head is really not bad at all. Your exhaust studs may be the biggest problem, but if they are seizing up then it is best to get them early. You will need a good valve disassembly tool to work on the head yourself, but you will pay a shop much more for them to do the work. Pull the valves and clean them on a wire wheel. Clean the combustion chambers and valve seats with small soft wire wheels on a cordless drill. Clean up the ports with a die grinder spinning those small sandpaper rolls (loosen the paper for the intakes). DO NOT hit the valve seats while using the die grinder! Decarbon the piston tops. Loosen the old valve seals by heating them with a propane torch. DO NOT scratch up the bucket tunnels! Install the new valve seals. Check the valve play in the valve guide. Lap the valves. Clean and reinstall the valves. Do a solvent test. Reinstall the head/cams with new gaskets. Check the valve clearances. Check the intake boots for integrity. Voila, ready for 100,000 miles of fun.
 
repark

repark

Next time you ride it and park it over night or longer, put it on its center stand and see if it does it next start up, go from there
 
If it hasn't been run for several years I wouldn't worry about it until you run the engine for several hours, It may be just a stuck ring
 
Give the bike a few good runs first before doing anything. If it has had infrequent use running a bit of fuel through it and getting it hot may do wonders. The valve stem seals probbaly are a bit hard, but so are mine (78GS1000) after I replaced then 20 years ago and 80,000kms ago, but it does not stop the bike going ok, just annoying.
 
Thanks for all the replies out there and sorry to leave you hanging. Anyway, what I've done in the last week, besides work and put about 1,000Kms. on the bike, was check compression (Cold 120,110,115,120: Hot 132,120,125,130) So all is well there. Even though the bike seemed to run great and idle smooth I borrowed some carb sticks and found the carbs to off quite a bit. So I synced the carbs and that got rid of most of the problems. Still get a little bit of blue smoke from the left pipe when cold for a few seconds but I'm not too worried about that. Oh yeah, I held off doing the carb sync because I had a K&N stock replacement filter on order which I finally got and installed prior to the carb sync. Thanks again for your replies. GSR ROCKS!!!
 
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