https://youtu.be/DnSeZaGf9Mw
That's what it sounds like.
Since I bought it (non-running) in June, I have replaced:
Oil & filter
Sparks
Battery
Fuel tank petcock and fuel lines
airbox (factory) and filter (K&N replacement)
There's fuel to carbs, there's spark at plugs. I don't know what to do next. I took carbs off and gave them the once over, but was hesitant to rebuild them.
compression? fuel&vacuum lines in correct places? timing might be wrong aswell.. cant be too big problem here..
Have you verified that there is spark? The GS500 has 3 switches that can prevent the engine from running.
- Clutch lever switch
- Side stand switch (when in gear)
- Kill switch on handlebar
Yes, there is spark.
Starter fluid in airbox doesn't give it life.
The fuel tank petcock is new, as are the fuel lines to the frame petcock. There's gas in the carbs.
I don't know how to assess compression or vacuum. Need help!
Quote from: struckjm on August 31, 2020, 02:21:05 PM
https://youtu.be/DnSeZaGf9Mw
That's what it sounds like.
Sound like very low or no compression, BUT I'm listening on a phone.
If it has spark and compression, it should fire on starting fluid.
Pull out a plug and see if it's wet with gas.
If you don't have a compression tester, hold a thumb over the plug hole and bump the stater.
It should push your finger away forcefully.
You can also do this with bike on the center stand, trans in fourth gear and rotate the rear wheel.
Can you recommend a compression tester? I am starting to feel like this may be the issue, a lack of compression or a total block of gas from carb in to engine.
All you need is a basic tester that has a 12mm adapter threads.
The tester needs to have the schrader valve in the end (tire valve core)
Avoid the harbor freight, Pittsburg and similar testers for $20 in a plastic box that read very low on a motorcycle (if you want any accuracy)
This Innova or Actron will be fine.
(https://iili.io/dZ61wl.md.jpg) (https://freeimage.host/i/dZ61wl)
(https://iili.io/dZtG5X.md.jpg) (https://freeimage.host/i/dZtG5X)
The OTC brand for about double the price are nicer and come in a good box, but you don't need to spend more for a tool you use infrequently.
Quote from: struckjm on September 01, 2020, 02:05:26 PM
Can you recommend a compression tester? I am starting to feel like this may be the issue, a lack of compression or a total block of gas from carb in to engine.
Even if the carb jets were plugged solid, it should fire on starting fluid.
Back to basics,
Air, fuel, compression and spark
Remember the four strokes... Suck, Squeeze, Bang, Blow. (Intake, Compression, ignition/power, exhaust)
It has to pull the air/fuel mixture in, then compress it for the spark to light it off.
If the valve timing events are off (or not happening) because of a cam chain failure.
If the cylinders are extremely worn or stuck piston rings,
There is no suck and no squeeze...
Now, if you find that you have compression... then you have see if the spark is happening at the correct time. (Ignition timing)
Quote from: Sporty on September 01, 2020, 09:40:50 AM
Sound like very low or no compression, BUT I'm listening on a phone.
If it has spark and compression, it should fire on starting fluid.
Pull out a plug and see if it's wet with gas.
If you don't have a compression tester, hold a thumb over the plug hole and bump the stater.
It should push your finger away forcefully.
You can also do this with bike on the center stand, trans in fourth gear and rotate the rear wheel.
The plugs are dry. " bump the stater." do you mean press the starter button?
If the plugs are dry, there's spark, and nothing happens, is it reasonable to test the carburetor by simply placing gas in the spark plug hole and seeing if it combusts?
I'm starting to think there's either no compression or no fuel is getting in to the cylinders.
Quote from: struckjm on September 01, 2020, 05:24:48 PM
Quote from: Sporty on September 01, 2020, 09:40:50 AM
Sound like very low or no compression, BUT I'm listening on a phone.
If it has spark and compression, it should fire on starting fluid.
Pull out a plug and see if it's wet with gas.
If you don't have a compression tester, hold a thumb over the plug hole and bump the stater.
It should push your finger away forcefully.
You can also do this with bike on the center stand, trans in fourth gear and rotate the rear wheel.
The plugs are dry. " bump the stater." do you mean press the starter button?
If the plugs are dry, there's spark, and nothing happens, is it reasonable to test the carburetor by simply placing gas in the spark plug hole and seeing if it combusts?
I'm starting to think there's either no compression or no fuel is getting in to the cylinders.
Yes, bump or "jog" the starter button, not hold it down. Just something to try in absence of a compression tester.
You can also put your hand or a small piece of plywood over the carb intake and see if there is a good "pull"
Just be careful of hands and fingers.
The staring fluid should make it run if the engine is mechanically ok and has spark in time.
Yes, You could try a little squirt of gas instead of the starting fluid.
I've blown the aerosol starter fluid into the airbox and then tried to start it with no difference.
did you have wide open throttle while you did it? just pour few drops of gas in sparkplug hole and start, its a guaranteed test for testing engine.. it bypasses the carb.. if it wont even try to start then theres some larger problem
Quote from: Sporty on September 01, 2020, 03:11:22 PM
Quote from: struckjm on September 01, 2020, 02:05:26 PM
Can you recommend a compression tester? I am starting to feel like this may be the issue, a lack of compression or a total block of gas from carb in to engine.
Even if the carb jets were plugged solid, it should fire on starting fluid.
Back to basics,
Air, fuel, compression and spark
Remember the four strokes... Suck, Squeeze, Bang, Blow. (Intake, Compression, ignition/power, exhaust)
It has to pull the air/fuel mixture in, then compress it for the spark to light it off.
If the valve timing events are off (or not happening) because of a cam chain failure.
If the cylinders are extremely worn or stuck piston rings,
There is no suck and no squeeze...
Now, if you find that you have compression... then you have see if the spark is happening at the correct time. (Ignition timing)
Compression gauge reads 0.0 PSI. Is that correct? I can feel pulses of air coming from plug hole or even exhaust pipe. The gauge is digital and it never reacts to the test on either cylinder. Just flat-lined.
So let's say it is right... then what? Rings, valves, other stuff... what kind of a head ache and or expense I am in for then?
So I am beginning to think that the cylinder has no compression.
I bought a digital gauge, and it reads 0.0 PSI. I hope it works right. If it does, there's literally NO compression at all.
I am no mechanical wizard, but I am willing to try and fix this myself.
Where do I start? What's the easiest or most likely culprit? I have been told cam timing and valve clearance on Reddit.
Are there any good Youtube videos out there for the GS500, or even the 450 (which I understand was basically the same engine) that go in depth over valve clearance checks, or cam timing checks?
Quote from: struckjm on September 06, 2020, 08:03:57 AM
So I am beginning to think that the cylinder has no compression.
I bought a digital gauge, and it reads 0.0 PSI. I hope it works right. If it does, there's literally NO compression at all.
I am no mechanical wizard, but I am willing to try and fix this myself.
Where do I start? What's the easiest or most likely culprit? I have been told cam timing and valve clearance on Reddit.
Are there any good Youtube videos out there for the GS500, or even the 450 (which I understand was basically the same engine) that go in depth over valve clearance checks, or cam timing checks?
If you're worried about the compression tester working, try it on another engine.
In your video, it sounded as if it was turning over fast with little to no resistance. That's what led me to think low or now compression.
I would remove the valve cover and see if the camshaft chain is intact and the cams are moving. Then worry about timing checks and valve clearance.
If you have a source of compressed air, you could also put air into the cylinder through the spark plug hole. That would find out if you have bent valves or very bad pistons/ cylinders. If you want to try it, I can give some more details.
This should help:
http://forum.gs500.pl/ftp/Studi/Suzuki_GS_500_E_F_1989-2009_Service_Manual.pdf
Thanks.
I found the Valve Clearance Check/Adjustment video from BaltimoreGS on Youtube, and it's not nearly as complicated as I feared.
In the video, I also got the impression I could assess the cam chain, cams and timing once the valve cover is off. Just be rotating the engine through a couple of turns.
Is it possible for a valve to be out of spec (too open or too closed) because of sitting a long time and getting stuck in position? If so, what's the fix for that?
Quote from: struckjm on September 06, 2020, 01:43:46 PM
Thanks.
I found the Valve Clearance Check/Adjustment video from BaltimoreGS on Youtube, and it's not nearly as complicated as I feared.
In the video, I also got the impression I could assess the cam chain, cams and timing once the valve cover is off. Just be rotating the engine through a couple of turns.
Is it possible for a valve to be out of spec (too open or too closed) because of sitting a long time and getting stuck in position? If so, what's the fix for that?
Yes, take the valve/cam cover off, rotate the engine and see if everything is moving,... if so check cam timing.
Valves can stick open.. doesn't happen a lot, but they can from corrosion, or bad fuel residue or serious overheating, lack of lubrication. (The last two usually have plenty of collateral damage)
Sticking closed, not really, not on an OHC engine, there is a lot of force from the cam to open the valve... just a fairly light spring to close it.
Pumping air into the cylinder will find a stuck open, bent or burnt valve.
If you have a stuck open valve that isn't bent or burnt, you might be able to remove the cams, the lifter bucket, get some penetrating oil in there and work the valve. Otherwise you pull the head off and bring it to an automotive machinist for repair.
What I don't know is how tight the valve to piston clearance is on the GS500. Some engines will bend valves when the cam chain break or a valve is stuck open (interference engines)
Other engines are ok (non-interference)
Parts came (feeler gauges, and new gaskets for breather and head) so I tore the top off today.
The cams look fine, the chain is correct, the timing appears to be correct. IE, all the marks (RT, chain marks etc) line up where they are supposed to when they are supposed to.
I was hoping I would see valves open and close visually, but that doesn't seem to be the case.
Valve clearances are less than .04mm, ie below spec. But I don't know by how much... Range is .03 to .08, and my .04 gauge is the smallest I have, and it won't insert at all, meaning actual clearances I assume are .03mm or less, the latter being more likely.
So is it simply valve clearance? Buy a few new shims and Voila? That doesn't seem right, but I definitely don't know really either. I also don't get how low/no clearance would result in 0.0PSI compression.
If it is as simple as shims, does a clearance of 0.00mm imply that if I went .05 or .1mm down on shim, I should be in the right place after? like if the current 2.50 = 0.00 clearance, than a 2.40 should give 1.0mm of clearance?
It's likely someone stuck shims in there that are too big and the valves are not closing. That would result in zero compression.
Only by removing the shims will you know what sizes they are. And only by temporarily installing thinner shims will you be able to measure the gaps. From there on you'll be able to calculate what sizes of shims are needed.
OK.
Feel like I am getting somewhere.
Can I get a corroborating 'amen' from anyone else that if the clearance is ~0.00mm that the valves are stuck open and the cylinder won't develop compression?
Any recommendations on those Suzuki Valve shim tools?
Best places to buy replacement shims? OEM seem to be about $14 where as aftermarket are like $4.
The next step that I would do, before anything else, is to put compressed air into the cylinder and see if it's leaking out one of the valves or into the crankcase.
You can use your compression tester hose as an adapter.
Most people won't have the matching quick connect. You can hose clamp an air hose on, Or, use the one from the gauge.
Remove the gauge and install the air supply hose (at one of the joints in red circles)
Be sure to remove the Schrader valve (tire valve core) from the hose. (Blue circle) Turn and hold the engine so both valves are close. This would be the pointy ends of the cam lobe both pointing up.
(https://iili.io/2AMVX2.md.jpg) (https://freeimage.host/i/2AMVX2)
Yes the valve clearance can be too tight, but it has to be so tight it's holding the valve open.
Can you spin the cam buckets (where the shims are) with the cam in the clearance checking position?
As far as buying shims, I bought them from Z1 enterprises.
The tool that I used was the Motion Pro (copy of Suzuki tool) It takes some getting used to.
I have read of makeshift tools, just the right size screwdriver, etc... the nice thing about the motion pro is that it keeps the bucket down while you work changing the shim.
I didn't save/ publish a photo of the tool in place. The center of the tool is a ramp the sits on the edge of the valve bucket. As you work the tool into place, the ramp pushes the bucket down. The ramp was kind of irregular and rounded. It kept slipping at first. I filed the ramp and got better at using it.
Here is a quote from my build thread.
Quote from: Sporty on September 08, 2020, 08:03:05 PM
I pulled the tappet shims to see the sizes. I had trouble with the motion pro tool slipping off the bucket edge. It's hard to see, but the part of the tool the pushes the bucket had a casting or forging line and was rounded. I filed it to be flatter and have a sharper , squared edge. It worked a bit better but still a PITA IMHO.
(https://iili.io/22X4BS.md.jpg) (https://freeimage.host/i/22X4BS)
(https://iili.io/22XgQ2.md.jpg) (https://freeimage.host/i/22XgQ2)
"Can you spin the cam buckets (where the shims are) with the cam in the clearance checking position"
I was able to do so on one, but the other two buckets were oriented in such a way that the recessed part you'd use for leverage wasn't really accessible. The one where it was approachable, I was able to rotate it using a flat head screwdriver. There was a little resistance. With the others, it's hard to say if the buckets would rotate or not since I couldn't really manipulate them. They certainly weren't free moving just by gently touching them with my finger or a screwdriver.
Quote from: struckjm on September 21, 2020, 06:23:00 PM
"Can you spin the cam buckets (where the shims are) with the cam in the clearance checking position"
I was able to do so on one, but the other two buckets were oriented in such a way that the recessed part you'd use for leverage wasn't really accessible. The one where it was approachable, I was able to rotate it using a flat head screwdriver. There was a little resistance. With the others, it's hard to say if the buckets would rotate or not since I couldn't really manipulate them. They certainly weren't free moving just by gently touching them with my finger or a screwdriver.
All four of mine rotated easily with a fingertip
Just did the 'oil in the spark plug hole' test and got an increase in compression.
Went from 0.0 up to a max of 11.4PSI with WOT and 10+ turns.
Quote from: Sporty on September 21, 2020, 08:06:59 PM
Quote from: struckjm on September 21, 2020, 06:23:00 PM
"Can you spin the cam buckets (where the shims are) with the cam in the clearance checking position"
I was able to do so on one, but the other two buckets were oriented in such a way that the recessed part you'd use for leverage wasn't really accessible. The one where it was approachable, I was able to rotate it using a flat head screwdriver. There was a little resistance. With the others, it's hard to say if the buckets would rotate or not since I couldn't really manipulate them. They certainly weren't free moving just by gently touching them with my finger or a screwdriver.
All four of mine rotated easily with a fingertip
The exhaust buckets almost seem frozen stuck. I can't get them to move to save my life, even if I rotate the cam lobe away.
Got all the shims fixed.
Both intakes are about .10mm clearance, so is one exhaust. Another exhaust is like .13mm.
Cold and head open, the left shows about 82 and the right about 99 psi.
Wouldn't start on first try, then did start with starter fluid.
Throttle response is sluggish, and after 5-10 starts it now revs suddenly to 4K, then drops off and dies.
Congratulations. It started at least! :thumb:
Quote from: struckjm on September 26, 2020, 09:55:51 AM
Got all the shims fixed.
Both intakes are about .10mm clearance, so is one exhaust. Another exhaust is like .13mm.
Cold and head open, the left shows about 82 and the right about 99 psi.
Wouldn't start on first try, then did start with starter fluid.
Throttle response is sluggish, and after 5-10 starts it now revs suddenly to 4K, then drops off and dies.
The good part is that you worked though a valve adjustment and made it run! :cheers:
The bad news is that the engine has low compression, carb issues and maybe an intake leak.
Id sort out the low compression next... leaky valves and/or worn cylinders and rings.
Quote from: Sporty on September 21, 2020, 05:32:19 PM
The next step that I would do, before anything else, is to put compressed air into the cylinder and see if it's leaking out one of the valves or into the crankcase.
You can use your compression tester hose as an adapter.
Most people won't have the matching quick connect. You can hose clamp an air hose on, Or, use the one from the gauge.
Remove the gauge and install the air supply hose (at one of the joints in red circles)
Be sure to remove the Schrader valve (tire valve core) from the hose. (Blue circle) Turn and hold the engine so both valves are close. This would be the pointy ends of the cam lobe both pointing up.
(https://iili.io/2AMVX2.md.jpg) (https://freeimage.host/i/2AMVX2)
Yes the valve clearance can be too tight, but it has to be so tight it's holding the valve open.
Can you spin the cam buckets (where the shims are) with the cam in the clearance checking position?
As far as buying shims, I bought them from Z1 enterprises.
The tool that I used was the Motion Pro (copy of Suzuki tool) It takes some getting used to.
I have read of makeshift tools, just the right size screwdriver, etc... the nice thing about the motion pro is that it keeps the bucket down while you work changing the shim.
I didn't save/ publish a photo of the tool in place. The center of the tool is a ramp the sits on the edge of the valve bucket. As you work the tool into place, the ramp pushes the bucket down. The ramp was kind of irregular and rounded. It kept slipping at first. I filed the ramp and got better at using it.
Here is a quote from my build thread.
Quote from: Sporty on September 08, 2020, 08:03:05 PM
I pulled the tappet shims to see the sizes. I had trouble with the motion pro tool slipping off the bucket edge. It's hard to see, but the part of the tool the pushes the bucket had a casting or forging line and was rounded. I filed it to be flatter and have a sharper , squared edge. It worked a bit better but still a PITA IMHO.
(https://iili.io/22X4BS.md.jpg) (https://freeimage.host/i/22X4BS)
(https://iili.io/22XgQ2.md.jpg) (https://freeimage.host/i/22XgQ2)
Can you recommend a cheap compressed air that would work with the compression gauge? Like a picture or amazon link?
Quote from: struckjm on September 29, 2020, 02:01:22 PM
Can you recommend a cheap compressed air that would work with the compression gauge? Like a picture or amazon link?
Do you have an air compressor?
No.
So I am trying to figure out what to buy to do a leak down test like you described earlier.
Quote from: Sporty on September 29, 2020, 02:12:46 PM
Quote from: struckjm on September 29, 2020, 02:01:22 PM
Can you recommend a cheap compressed air that would work with the compression gauge? Like a picture or amazon link?
Do you have an air compressor?
Could this work?
(http://mobileimages.lowes.com/product/converted/027488/027488605381_11621569.jpg?size=pdhi)
or does it gotta be something like this:
(http://mobileimages.lowes.com/product/converted/871613/871613009472.jpg?size=pdhi)
Something with a tank like #2.
However, with the 25 PSI increase with oil, you have significant ring seal/ cylinder wear.
The threads are getting parallel now...i replied to both.
Quote from: Sporty on October 02, 2020, 07:53:44 PM
Something with a tank like #2.
However, with the 25 PSI increase with oil, you have significant ring seal/ cylinder wear.
The threads are getting parallel now...i replied to both.
I know! Sorry! I ordered a 3 gal compressor for $70. I'll find other uses for it later for sure.
Should help to clarify where the leak is, but I think we both think it's in the rings.
If I am reading correctly, piston ring seal failure would result in air coming out the dip stick or lower engine. Does that sound correct?
Quote from: struckjm on October 03, 2020, 06:49:20 AM
Quote from: Sporty on October 02, 2020, 07:53:44 PM
Something with a tank like #2.
However, with the 25 PSI increase with oil, you have significant ring seal/ cylinder wear.
The threads are getting parallel now...i replied to both.
I know! Sorry! I ordered a 3 gal compressor for $70. I'll find other uses for it later for sure.
Should help to clarify where the leak is, but I think we both think it's in the rings.
If I am reading correctly, piston ring seal failure would result in air coming out the dip stick or lower engine. Does that sound correct?
Yes
Welp. We'll find out soon.
compressor and leak down gauge arrive tomorrow.
thanks amazon.