help! won't start

[Steve]

i have no clue when the valves were last adjusted. I'm sure they're past due for an adjustment. i do have fuel in the float bowls, just put a new petcock on a few months ago. i think i'm going to get a full carb o-ring set and dip the carbs again just to rule it out. i really appreciate the replies! i'll keep ya posted as i get time to work on it. thanks!

Thanks for the reply and confirmation of my guess.

While you are waiting for the carbs in the dip, why not adjust the valves, too?

Of course, that would mean that you changed two items, so you won't know which one of them actually cured your problem, but they both need to be done, so it doesn't really matter.

.

[hansimusmaximus]

Here's how you confirm your problem

1. Take out all 4 spark plugs
2. Using a small hose or syringe, put up to an ounce of gas in each cylinder
4. Reinstall plugs
5. Try to start

If it pops or tries to start, your carbs are still plugged up.

i just tried this. it popped and ran for a second then died. so the carbs are still the culprit?

[chef1366]

Check compression also but all signs point to carbs being clogged

http://www.thegsresources.com/_forum/showthread.php?t=148764

[Steve]

Come to think of it, my first question has not been answered either.

Well, the first question is going to be:
How did you clean the carbs?

But, then, neither has this one:

Third question:
How are you trying to start it? Proper procedure (after priming the float bowls) is to apply full "choke", NO throttle, pull the clutch, press the starter button.

Next issue:

... I don't think these symptoms are caused by tight valves. For the valves to be that out of adjustment, ALL of the valves would need to remain slightly open so that no cylinders produced the vacuum needed to draw fuel and air into them. ...

Not necessarily. The intake valves close after the piston is already on the upward stroke. Usually, there is enough inertia in the incoming air to pack a little more air in by the time the valve closes. If the valves are just a little tight (still some clearance, not none), they will close later in the piston's travel. Maybe late enough that the piston actually pushes some of the mix back through the carb. Air moving across the carb jets will pick up fuel. Since it has already been by there before, it will richen up the mixture a bit more. Next time the valve opens, air will be drawn over the jets a THIRD time, making it even richer. By now, it's too rich to burn and not enough has stayed in the cylinder to get the engine to run.

Some that are desparate to get the engine to run will have sprayed some starting fluid in there by now, and some of that might have stayed in the cylinder and, because it is so volatile, would have managed to start the engine. The profound discovery now is that "this engine is so cold-blooded, it needs starting fluid to get it going", so that is what is now used.

As the engine warms up, the actual clearance at the valve will change, due to the expansion of the aluminum in the head. This change in clearance delays the valve timing enough that warm starts are made with no problem, mentally reinforcing the conception that the bike is, indeed, cold-blooded.

All of this frustration in spite of the fact that a simple valve adjustment will fix it all. Clean carbs will then ensure that the right amount of fuel will be metered into the airflow. Proper starting technique will help even more.

.

[greg78gs750]

+1 on all this very good, classic advice.

Come to think of it, my first question has not been answered either.

But, then, neither has this one:



Next issue:

Not necessarily. The intake valves close after the piston is already on the upward stroke. Usually, there is enough inertia in the incoming air to pack a little more air in by the time the valve closes. If the valves are just a little tight (still some clearance, not none), they will close later in the piston's travel. Maybe late enough that the piston actually pushes some of the mix back through the carb. Air moving across the carb jets will pick up fuel. Since it has already been by there before, it will richen up the mixture a bit more. Next time the valve opens, air will be drawn over the jets a THIRD time, making it even richer. By now, it's too rich to burn and not enough has stayed in the cylinder to get the engine to run.

Some that are desparate to get the engine to run will have sprayed some starting fluid in there by now, and some of that might have stayed in the cylinder and, because it is so volatile, would have managed to start the engine. The profound discovery now is that "this engine is so cold-blooded, it needs starting fluid to get it going", so that is what is now used.

As the engine warms up, the actual clearance at the valve will change, due to the expansion of the aluminum in the head. This change in clearance delays the valve timing enough that warm starts are made with no problem, mentally reinforcing the conception that the bike is, indeed, cold-blooded.

All of this frustration in spite of the fact that a simple valve adjustment will fix it all. Clean carbs will then ensure that the right amount of fuel will be metered into the airflow. Proper starting technique will help even more.

.

[kevinmccaffrey]

won't start?

compression; as stated earlier has to be verified....eg. valve clearances.... ignition timing.. check..... firing order?,,.check big FAT sparks??.. check FRESH fuel?..check fuel/wet plugs? check on/off button?...check choke?..check clutch in/disengauged? check fully charged battery..check key on....AWAY YOU GO!!!

[49er]

[QUOTE



Next issue:

Not necessarily. The intake valves close after the piston is already on the upward stroke. Usually, there is enough inertia in the incoming air to pack a little more air in by the time the valve closes. If the valves are just a little tight (still some clearance, not none), they will close later in the piston's travel. Maybe late enough that the piston actually pushes some of the mix back through the carb. Air moving across the carb jets will pick up fuel. Since it has already been by there before, it will richen up the mixture a bit more. Next time the valve opens, air will be drawn over the jets a THIRD time, making it even richer. By now, it's too rich to burn and not enough has stayed in the cylinder to get the engine to run.

Some that are desparate to get the engine to run will have sprayed some starting fluid in there by now, and some of that might have stayed in the cylinder and, because it is so volatile, would have managed to start the engine. The profound discovery now is that "this engine is so cold-blooded, it needs starting fluid to get it going", so that is what is now used.

As the engine warms up, the actual clearance at the valve will change, due to the expansion of the aluminum in the head. This change in clearance delays the valve timing enough that warm starts are made with no problem, mentally reinforcing the conception that the bike is, indeed, cold-blooded.

All of this frustration in spite of the fact that a simple valve adjustment will fix it all. Clean carbs will then ensure that the right amount of fuel will be metered into the airflow. Proper starting technique will help even more.

.[/QUOTE]

All true, but doesn't this confirm that there is still a possibility that some air fuel mix will partially ignite, as in at least getting a kickback or explosion through the exhaust? The owner reported that this was not happening, so the conclusion is that fuel was not getting into the chambers. Spark was reported to be good.

If posters would only follow suggestions, or at least say that they hadn't, the lot of a diagnostic guru would be so much easier.

[chef1366]

Steve and Ian are the GS gurus.

[49er]

Steve and Ian are the GS gurus.

Bill's the GS1100 (4 valve) engine guru. He holds the record for the fastest head removal and replace. I can't quote the time, but I'm told it's impressive.

He knows a fair bit about pistons and head gaskets too.

[chef1366]

Bill's the GS1100 (4 valve) engine guru. He holds the record for the fastest head removal and replace. I can't quote the time, but I'm told it's impressive.

He knows a fair bit about pistons and head gaskets too.

Oh the fun never stops!
The fun starts for me with my new 1230 engine.

[doctorgonzo]

Oh the fun never stops!
The fun starts for me with my new 1230 engine.

I'm joining you, sent the deposit off to Ray today for my 1230. Quite a deal, got the whole shebang for what the pisons cost new retail.

[chef1366]

I'm joining you, sent the deposit off to Ray today for my 1230. Quite a deal, got the whole shebang for what the pisons cost new retail.

You bought the 18mm wrist pin 1230 kit!
Good for you.
It was a great deal. I would of jumped on it but I already worked out a deal for an 1150 crank (20mm wrist pins)

[doctorgonzo]

You bought the 18mm wrist pin 1230 kit!
Good for you.
It was a great deal. I would of jumped on it but I already worked out a deal for an 1150 crank (20mm wrist pins)

Yes sir. Sent Mr Ray 1/3 down today, and going to send him the balance after I recover from Christmas.

[Steve]

Steve and Ian are the GS gurus.

I don't know about that.

Let's just say that I have been there, done that, and have (had) the receipts to prove it. I think I gave all my receipts to the guy that bought my Voyager three years ago, but I seem to remember the bill to rebuild the engine was just a touch over $3,000. It was getting harder and harder to start when cold. It got to the point that I would connect the hose to the outlet of my shop-vac and blow it into the airbox. That helped keep all the air moving in the right direction with a very mild form of supercharging. When I left work in the afternoon, if it didn't start on the first push of the button, I would aim the bike downhill and bump-start it. Don't know why, but it seemed to work better that way. With the poor running there were excessive carbon build-ups on the pistons that actually bent a couple of intake valves, forcing the engine rebuild. Six new intake valves, a fresh touch-up of the valve seats, new valve seals, new rings on the pistons, freshly-honed cylinders and a few other necessary bits and the bike ran like new. A few months (and several thousand miles) later, the bike was getting hard to start AGAIN. I mentioned that to the dealer that had just done the work, and they suggested I bring it in for valve adjustment. I assured them that I could do the job, as long as that was all they felt was wrong. A couple of hours and half a dozen (thinner) shims later, the bike was running like new again. If I had only known the reason for the hard starting at the beginning of all this, I could have saved over $3,000. Now you know why I preach that sermon so enthusiastically on this forum.

.

[49er]

I don't know about that.

Let's just say that I have been there, done that, and have (had) the receipts to prove it. I think I gave all my receipts to the guy that bought my Voyager three years ago, but I seem to remember the bill to rebuild the engine was just a touch over $3,000. It was getting harder and harder to start when cold. It got to the point that I would connect the hose to the outlet of my shop-vac and blow it into the airbox. That helped keep all the air moving in the right direction with a very mild form of supercharging. When I left work in the afternoon, if it didn't start on the first push of the button, I would aim the bike downhill and bump-start it. Don't know why, but it seemed to work better that way. With the poor running there were excessive carbon build-ups on the pistons that actually bent a couple of intake valves, forcing the engine rebuild. Six new intake valves, a fresh touch-up of the valve seats, new valve seals, new rings on the pistons, freshly-honed cylinders and a few other necessary bits and the bike ran like new. A few months (and several thousand miles) later, the bike was getting hard to start AGAIN. I mentioned that to the dealer that had just done the work, and they suggested I bring it in for valve adjustment. I assured them that I could do the job, as long as that was all they felt was wrong. A couple of hours and half a dozen (thinner) shims later, the bike was running like new again. If I had only known the reason for the hard starting at the beginning of all this, I could have saved over $3,000. Now you know why I preach that sermon so enthusiastically on this forum.

.

Well done Steve. Confession is good for the soul.

I had a similar experience with my 850, but it had nothing to do with poor valve clearances.

Mine started to smoke when the air temps got higher and I was flogging it. Also, there was a white vapour coming from the carbs /airbox region, every time I returned from a run. Snapping the throttle open before shut down produced a nice light blue smoke from the 4-1. I surmised that I had a sad set of rings. I had not found the GSR at this stage, but I did do a compression test and found fairly consistent numbers, 110 -125 psi was the range. I thought that this wasn't terribly exciting, so i decided that the engine could do with a bit of hopping up. There were no aftermarket HC kits available for the 850's so I decided to fit up some custom JE pistons.

During the rebuild, I found the the airbox breather vent was completely blocked through years of condensation. This had caused the crankcase to pressurise, forcing oil past the cam chain tensioner seals, the tacho drive seal, the oil pressure sensor and finally, the piston rings.

I have never regretted fitting the HC pistons, but I wonder what stage of tune my 850 would be in now, had I known what was causing the blowby at the rings in the first place.