Around 2 years ago - i purchased non running rusty GS500. I like them so I decided to give it a go and take it apart and clean, repair, polish, fix, paint and put it back together. It worked well - until I ran into oil pressure problem. It simply has no oil pressure.
1. I can start it and it runs OK but no oil pressure light. (That is why i do not mess around with it and shut it down quickly)
2. I have checked the wiring - tested the sensor - everything is fine.
3. Recently I replaced the oil pressure sensor. NO solution there.
4. I got pissed - and ordered oil pump replacement. Nothing Changed.
5. Then one day I raged and reved it up to 6K and Oil Light dissipated. What could that mean - oil pressure only on extreme revs?!?
Until today it is collecting dust as I ran out of ideas what is wrong with it. I would love to fix this last issue and finally get it on the road.
A few things to mention - that might or might not help for your valuable comment / suggestion.
1. When I got it - it felt like it was put together out of non compatible parts. It had a wiring and ECU from newer model. replaced it with correct one.
2. It had no pressure in left piston adn valve was not closing fully - replaced rings and exhaust valve. Compression back to normal.
3. I tried to run it without oil filter as some told that bad filter could cause low pressure. Nothing changed.
4. I have noticed a bit of metal dust when pulling off bottom cover. Since I was filling and draining it on daily basis - happen to notice that.
5. I noticed that cylinder block has some weird holes right next to exhaust hole. First time I started the they made hell of a noise blowing out exhaust from them. I googled and found out that this was for some french models - something to do with emission filtering. I most definately dont have that exhaust unit so I just closed them up with some plates and bolts.
This cylinder block head (top) is my next suspicious item to replace as it feels like oil just simply is not flowing through somewhere (there are no clogs - engine was pulled and washed and cleaned) and this unit seems like one more peace off different bike.
My Bike is:
Suzuki GS500E 1997
15000KM
Thank you for your kind welcome to forum and I hope you will be able to help me with this problem.
Oil pressure only @ 6K or higher ???
OK you should try to put a gauge in that fitting and read it. The thing makes dismal oil pressure when its fully warmed up, but it does make a ton when cold.
Now you have the oil filter and what not installed correct ???? the spring etc - if not, you wont make nothing for oil pressure.
Cool.
Buddha.
Hey BTW you do need a fork brace before that's rideable.
Agree with Buddha, put a gauge on it and rule out the sensor.
Given what other things you told us about the shape of the engine, it seems fair to suspect the cause of low oil pressure is the classic cause: worn main bearing, rod bearings, etc.
Actually the stock fork brace does pretty well nothing. It is too thin especially at the bolt holes. It is really not much more than a mudguard holder.
Considering the axle setup adds stuffall to the torsional stiffness of the forks , it is always worth making a proper stiffner. Certainly an easy job compared to most bikes as it is just a flat plate with holes.
Quote from: The Buddha on January 22, 2018, 12:06:51 PM
Oil pressure only @ 6K or higher ???
OK you should try to put a gauge in that fitting and read it. The thing makes dismal oil pressure when its fully warmed up, but it does make a ton when cold.
Now you have the oil filter and what not installed correct ???? the spring etc - if not, you wont make nothing for oil pressure.
Cool.
Buddha.
Hi.
Thank you for your comment.
I am sorry - my story was not clear. I have installed new oil filter. I just saw somewhere that cheap filters might be a problem and since I did not spend a fortune and it was cheap indeed - i tried to remove it. But it did not make any difference. So the filter is back in. The spring is on it and the cover on top. It is close to impossible to put it in the wrong way :)
Will search for a proper oil pressure tool and update on my trial and error journey.
Quote from: mr72 on January 22, 2018, 12:47:53 PM
Hey BTW you do need a fork brace before that's rideable.
Agree with Buddha, put a gauge on it and rule out the sensor.
Given what other things you told us about the shape of the engine, it seems fair to suspect the cause of low oil pressure is the classic cause: worn main bearing, rod bearings, etc.
Hello Mr72.
Thank you for your reply.
I do have it on my table. I have not assembled it jet - as this oil failure keeps my mind busy and the rest is just bits and peaces.
Well the gauge is telling me 15000 but remember what i wrote about wrong wiring on it. And my suspicion that cylinder block is out of french model. I would not count on anything and will reconsider any options.
Regarding your guess - is this a common problem for GSTwins? Lets assume I test it with gauge and there is still no oil pressure...
By rod bearings you mean these funny C shape plates? And if I go for replacement - do I replace them all?
And what do you mean by main bearing? Which one is that?
What other items go under "classic cause"?
Thank you for your reply. Looking forward.
Quote from: gregjet on January 22, 2018, 01:18:29 PM
Actually the stock fork brace does pretty well nothing. It is too thin especially at the bolt holes. It is really not much more than a mudguard holder.
Considering the axle setup adds stuffall to the torsional stiffness of the forks , it is always worth making a proper stiffner. Certainly an easy job compared to most bikes as it is just a flat plate with holes.
Hello Gregjet.
Thank you for your tip. I will definitely look into it but at the moment my mind is so occupied with this oil issue. As soon as I sort that - i will happily continue to make this bike as mint as possible.
nauzers. I don't want to offend you, but mate, -you need help from someone who knows motorcycle engines.
It looks to me as though you may be chasing problems without enough expertise.
Like for example, when the oil pressure light goes OUT it means you have GOOD oil pressure, -your first post said "runs OK but no oil pressure light".
What is it that makes you think you have low or no oil pressure?
And you've fitted a new oil pump? Oil pumps typically last the life of 2 engines!
Have you checked that oil is getting up top to the cams and rocker covers?
So if you've done the rings on one piston you must have pulled the cylinders off, - so how did the big ends feel? If you're losing pressure at the big ends the big end slop will be very noticeable.
Etc etc...
Quote from: nauzers on January 22, 2018, 10:02:53 PM
Well the gauge is telling me 15000 but remember what i wrote about wrong wiring on it. And my suspicion that cylinder block is out of french model. I would not count on anything and will reconsider any options.
By "cylinder block" you mean the cylinders themselves, right? I think this part is commonly called the "jug" by motorcycle mechanics. Just to aid in clear communication here.
The holes you are talking about, are they beneath the exhaust outlets? If so that's probably the PAIR outlets, which are commonly covered with no ill effects. It's exhaust, not oil. See this thread for a little more detail (http://gstwins.com/gsboard/index.php?topic=40142.0).
Quote
Regarding your guess - is this a common problem for GSTwins? Lets assume I test it with gauge and there is still no oil pressure...
No... in fact it seems quite rare from my own perusal of GSTwins forum and other research I have done. The bottom end of these engines seems to be quite durable compared with the top end. But it's not impossible to have spun a rod bearing. You'd normally hear a knock when it runs, it'd be pretty obvious to someone who is familiar with the sound of a properly-running GS500. This is commonly known as "rod knock" and it's the dying gasp of a worn out engine.
Quote
By rod bearings you mean these funny C shape plates? And if I go for replacement - do I replace them all?
Yes, they are funny C shaped plates... really look more like bushings split into halves rather than bearings in the sense that we are used to ("ball" bearings).
You have to basically completely dismantle the bottom end of the engine to get to them. You would never do that without replacing them all, including every other gasket, seal, and bearing you can get to while it's apart. This is known as a "bottom end rebuild". Usually you need the assistance of a machine shop.
Quote
And what do you mean by main bearing? Which one is that?
The rod bearings sit between the rod ends (which have sort of a hole in them) and the crankshaft. The similar-looking bearings that hold the crankshaft in the block are commonly known as "main bearings" or "crank bearings".
You replace this all at once. And there are probably also thrust bearings that would need to be replaced as well, you'd not know what size you need until you get the crankshaft [and maybe crankcase] back from the machine shop.
I am speaking in general terms here, this is ordinary engine rebuilding 101. There are many others on this forum who have lots of direct experience with GS450 and GS500 engines in particular who can steer you correctly.
This is a very big job.
Quote
What other items go under "classic cause"?
Low oil pressure is usually caused by one of the following:
- low oil -- far and away the most common! I presume you have checked and rechecked that, right? and not on the side stand, since you will get a high reading...
- a massive leak somewhere that's not supposed to be leaking, like a crack in the block or some broken part in the engine block somewhere -- rare unless there's been mechanical trauma (a wreck, impact, etc.) or something inside the engine broke and took other things with it ("thrown rod" etc.)
- a failed oil pump (which as you know is not the cause in your case) - reportedly rare in a GS500 but one could be defective or get damaged by running the engine low on oil, running it with no oil filter, other junk in the engine oil getting lodged in the oil pump, etc.
- a clog in the oil galleys somewhere, like some piece of debris or whatever that got past the oil filter and is lodged in the oiling system
- severely worn / cracked / broken / missing main (crank) or rod bearing
- anecdotally not common in GS500s but maybe it's because nobody keeps them long enough to wear this out. In water cooled automobile engines for street-driven cars normally these bearings last 200K+ miles or twice as long at least as the rings. I'd guess it's maybe half that for an air-cooled motorcycle, but that's just a guess, and like I say rarely do you see a GS500 with 100K miles so rarely should you see bad crank and rod bearings.
I'd venture those are the "classic" causes of low oil pressure.
I'd say if you rule out the obvious and easy, which is low oil, missing oil filter, then the remaining candidates all have the same remedy which is a complete bottom end engine overhaul. Given the possibility of buying a replacement engine with good oil pressure, I'd say you'd really only want to rebuild the entire engine if it has some kind of sentimental value. Or you just crave the experience. It's not going to be cheaper than buying another engine with only 15K on it.
So if I were in your shoes I'd absolutely verify my oil level, make sure I have the correct oil filter, and then check the oil pressure with a gauge. Certainly the factory service manual or even a Haynes manual has a procedure and the right numbers, so I won't venture what they should be. But once you verify it indeed has low oil pressure and the easy things are ruled out, then I'd replace the engine and not spend another minute diagnosing this one. Find a used engine where you can see it run and verify the oil pressure yourself with a gauge prior to buying (or with some kind of warranty).
If you wanted to rebuild it yourself then you have a lot to learn but it's easy enough to learn it all and get it right. It'll be very helpful for you to have a local friend who has done it before a few times who can give you hands on advice. Plenty of people do it, but it'll be much easier to just replace it and probably not any more costly.
Quote from: Joolstacho on January 23, 2018, 02:14:30 AM
nauzers. I don't want to offend you, but mate, -you need help from someone who knows motorcycle engines.
It looks to me as though you may be chasing problems without enough expertise.
Like for example, when the oil pressure light goes OUT it means you have GOOD oil pressure, -your first post said "runs OK but no oil pressure light".
What is it that makes you think you have low or no oil pressure?
And you've fitted a new oil pump? Oil pumps typically last the life of 2 engines!
Have you checked that oil is getting up top to the cams and rocker covers?
So if you've done the rings on one piston you must have pulled the cylinders off, - so how did the big ends feel? If you're losing pressure at the big ends the big end slop will be very noticeable.
Etc etc...
Hello Joolstacho.
I am sorry - this is my bad - i did explain it in a weird way. What i mean is - the light is not going away. Its there all the time.
You are right - I am totally no engineer - but i know some stuff and not afraid to learn more.
This GS is more like a toy and hobby - and now a challenge. Taking it to shop will cost more than the whole bike... :)
I've never seen a bike not make oil pressure till 6k and still run for more than 30 sec.
Cool.
Buddha.
Quote from: mr72 on January 23, 2018, 06:32:19 AM
Quote from: nauzers on January 22, 2018, 10:02:53 PM
Well the gauge is telling me 15000 but remember what i wrote about wrong wiring on it. And my suspicion that cylinder block is out of french model. I would not count on anything and will reconsider any options.
By "cylinder block" you mean the cylinders themselves, right? I think this part is commonly called the "jug" by motorcycle mechanics. Just to aid in clear communication here.
The holes you are talking about, are they beneath the exhaust outlets? If so that's probably the PAIR outlets, which are commonly covered with no ill effects. It's exhaust, not oil. See this thread for a little more detail (http://gstwins.com/gsboard/index.php?topic=40142.0).
Quote
Regarding your guess - is this a common problem for GSTwins? Lets assume I test it with gauge and there is still no oil pressure...
No... in fact it seems quite rare from my own perusal of GSTwins forum and other research I have done. The bottom end of these engines seems to be quite durable compared with the top end. But it's not impossible to have spun a rod bearing. You'd normally hear a knock when it runs, it'd be pretty obvious to someone who is familiar with the sound of a properly-running GS500. This is commonly known as "rod knock" and it's the dying gasp of a worn out engine.
Quote
By rod bearings you mean these funny C shape plates? And if I go for replacement - do I replace them all?
Yes, they are funny C shaped plates... really look more like bushings split into halves rather than bearings in the sense that we are used to ("ball" bearings).
You have to basically completely dismantle the bottom end of the engine to get to them. You would never do that without replacing them all, including every other gasket, seal, and bearing you can get to while it's apart. This is known as a "bottom end rebuild". Usually you need the assistance of a machine shop.
Quote
And what do you mean by main bearing? Which one is that?
The rod bearings sit between the rod ends (which have sort of a hole in them) and the crankshaft. The similar-looking bearings that hold the crankshaft in the block are commonly known as "main bearings" or "crank bearings".
You replace this all at once. And there are probably also thrust bearings that would need to be replaced as well, you'd not know what size you need until you get the crankshaft [and maybe crankcase] back from the machine shop.
I am speaking in general terms here, this is ordinary engine rebuilding 101. There are many others on this forum who have lots of direct experience with GS450 and GS500 engines in particular who can steer you correctly.
This is a very big job.
Quote
What other items go under "classic cause"?
Low oil pressure is usually caused by one of the following:
- low oil -- far and away the most common! I presume you have checked and rechecked that, right? and not on the side stand, since you will get a high reading...
- a massive leak somewhere that's not supposed to be leaking, like a crack in the block or some broken part in the engine block somewhere -- rare unless there's been mechanical trauma (a wreck, impact, etc.) or something inside the engine broke and took other things with it ("thrown rod" etc.)
- a failed oil pump (which as you know is not the cause in your case) -- reportedly rare in a GS500 but one could be defective or get damaged by running the engine low on oil, running it with no oil filter, other junk in the engine oil getting lodged in the oil pump, etc.
- a clog in the oil galleys somewhere, like some piece of debris or whatever that got past the oil filter and is lodged in the oiling system
- severely worn / cracked / broken / missing main (crank) or rod bearing -- anecdotally not common in GS500s but maybe it's because nobody keeps them long enough to wear this out. In water cooled automobile engines for street-driven cars normally these bearings last 200K+ miles or twice as long at least as the rings. I'd guess it's maybe half that for an air-cooled motorcycle, but that's just a guess, and like I say rarely do you see a GS500 with 100K miles so rarely should you see bad crank and rod bearings.
I'd venture those are the "classic" causes of low oil pressure.
I'd say if you rule out the obvious and easy, which is low oil, missing oil filter, then the remaining candidates all have the same remedy which is a complete bottom end engine overhaul. Given the possibility of buying a replacement engine with good oil pressure, I'd say you'd really only want to rebuild the entire engine if it has some kind of sentimental value. Or you just crave the experience. It's not going to be cheaper than buying another engine with only 15K on it.
So if I were in your shoes I'd absolutely verify my oil level, make sure I have the correct oil filter, and then check the oil pressure with a gauge. Certainly the factory service manual or even a Haynes manual has a procedure and the right numbers, so I won't venture what they should be. But once you verify it indeed has low oil pressure and the easy things are ruled out, then I'd replace the engine and not spend another minute diagnosing this one. Find a used engine where you can see it run and verify the oil pressure yourself with a gauge prior to buying (or with some kind of warranty).
If you wanted to rebuild it yourself then you have a lot to learn but it's easy enough to learn it all and get it right. It'll be very helpful for you to have a local friend who has done it before a few times who can give you hands on advice. Plenty of people do it, but it'll be much easier to just replace it and probably not any more costly.
Thank you for your valuable input. I will chase down this oil pressure gauge. And if it fails - will make my final decision - what to do with it.
OK here is the manual on the subject and it covers pretty well all the possible basic .
"OIL PRESSURE SPECIFICATION
Above 200 kPa (2.0 kg/cm2 , 28 psi)
Below 500 kPa (5.0 kg/cm2 , 71 psi)
at 3 000 r/min., Oil temp. at 60°C (140° F)
If the oil pressure is lower or higher than the specification, the following causes may be considered.
LOW OIL PRESSURE
* Clogged oil filter
* Oil leakage from oil passage way
* Damaged oil seal
* Defective oil pump
* Combination of above items
HIGH OIL PRESSURE
* Used a engine oil which is too heavy a weight
* Clogged oil passage way
* Combination of above items
OIL PRESSURE TEST PROCEDURE
Start the engine and check if the oil pressure indicator light is
turned on. If it keeps on lighting, check the oil pressure indicator
light circuit. If it is in good condition, check the oil pressure
in the following manner.
• Install the oil pressure gauge CD in the position shown in the
figure.
• Warm up the engine as follows:
Summer 10 min. at 2 000 r/min.
Winter 20 min. at 2 000 r/min.
• After warming up, increase the engine speed to 3 000 r/min.
with the engine tachometer reading, and read the oil pressure
gauge.
09915-7451 0 : Oil pressure gauge
09915-77330 : Meter (for high pressure)"
Reference Suzuki GS500 manual.
Have you checked it actually has a filter in it? That will do it if it hasn't, as well as a clogged one.
Another one. Does anyone know for sure what the oil pump driven gear is made from. When this bike was designed it was fashionable to make that gear from nylon or reinforced fibre. I have seen them stripped and that gives the high rpm pumping because it is being friction driven. Particularly prevelant on SR250 yamahas.
Quote from: gregjet on January 23, 2018, 01:46:50 PM
OK here is the manual on the subject and it covers pretty well all the possible basic .
"OIL PRESSURE SPECIFICATION
Above 200 kPa (2.0 kg/cm2 , 28 psi)
Below 500 kPa (5.0 kg/cm2 , 71 psi)
at 3 000 r/min., Oil temp. at 60°C (140° F)
If the oil pressure is lower or higher than the specification, the following causes may be considered.
LOW OIL PRESSURE
* Clogged oil filter
* Oil leakage from oil passage way
* Damaged oil seal
* Defective oil pump
* Combination of above items
HIGH OIL PRESSURE
* Used a engine oil which is too heavy a weight
* Clogged oil passage way
* Combination of above items
OIL PRESSURE TEST PROCEDURE
Start the engine and check if the oil pressure indicator light is
turned on. If it keeps on lighting, check the oil pressure indicator
light circuit. If it is in good condition, check the oil pressure
in the following manner.
• Install the oil pressure gauge CD in the position shown in the
figure.
• Warm up the engine as follows:
Summer 10 min. at 2 000 r/min.
Winter 20 min. at 2 000 r/min.
• After warming up, increase the engine speed to 3 000 r/min.
with the engine tachometer reading, and read the oil pressure
gauge.
09915-7451 0 : Oil pressure gauge
09915-77330 : Meter (for high pressure)"
Reference Suzuki GS500 manual.
Have you checked it actually has a filter in it? That will do it if it hasn't, as well as a clogged one.
Another one. Does anyone know for sure what the oil pump driven gear is made from. When this bike was designed it was fashionable to make that gear from nylon or reinforced fibre. I have seen them stripped and that gives the high rpm pumping because it is being friction driven. Particularly prevelant on SR250 yamahas.
Thank you Gregjet for your post.
Yes - I have a manual and I saw this section.
* Clogged oil filter - One of the first things was replacing an oil filter. I have installed Hiflo - brand new.
* Oil leakage from oil passage way - not too sure how to check that. Based on drawings - the oil route is quite simple. I pulled off most of the covers - had a look with flashlight all around. Pushed some wire through to make sure all lines are clear - could not spot anything unusual.
* Damaged oil seal. Nut sure I understand this one - All external seals are perfect. Not a single drop. But it might mean something inside. But as far as I saw - pretty much whole bottom part is holding oil.
* Defective oil pump. I have replaced it. Both new and old looked the same and felt the same - i think it was waste of money but wanted to be sure.
Will keep investigating.
Thank you for your support.
A few things I did - it might be a sign of smth.
1. When you pull out oil filter - on a far side of oil filter chamber bottom - there is a little allen key bolt. Any ideas what it does and what is it for? Manual does not seem to show it.
2. Since I have not got my oil tester jet - i raged again and pulled out oil pressure sensor and started the bike. I was prepared for massive oil squirt - but nothing came out of the hole. I run it for 10 sec max. It feels super wrong to me but again - im not an expert to judge.
It feels like I have to harvest it out of frame and slice it apart. I feel confident - especially with your great support.
Thank you all for your input. I will keep this post going with updates and hopefully one day will catch a breeze riding this little guy.
P.S. Checked the engine price around - they all want crazy prices. And since it was my hobby / training / skill pump project. Will carry on doing it on my own.
Just realized I cant quite understand how faulty crank / thrust / rod bearings cause low pressure. How do they influence pressure? I hope its not too much to ask a little explanation?
And when i go for rebuild - is that my shopping list?
1. Rod Bearings
2. Thrust Bearings
3. Crank Bearings
4. Seals - can i use gasket sealant?
What else do i have to add to my list?
A rebuild like that -crank, mainbearings and big-endbearings, and associated parts may well cost you more than a good second hand engine.
You'll need a complete engine gasket set, they're not too expensive, but just sealant will not do.
Wear in the big-ends causing loss of oil pressure: The oil is being pumped through fine drillings in the crankshaft and is forced out into the big-end shells for lubrication because the clearance between the journal and shell is very close. When the shells wear, the oil, instead of being forced into the shells/journals interface, can escape out the sides, so pressure is lost to the big end.
I would always replace the camchain and tensioner. Budget for valve shims too.
This thread may interest you.:
http://gstwins.com/gsboard/index.php?topic=58696.0
I would expect at least some oil to be pushed out of the oil switch hole even with shot mains.
Just putting this out there.. you didn't misplace the pin in the oil pump shaft? Or the gear isn't damaged as suggested by Grejet.
Fair bit of disassembly to check but clearly something isn't as it should be.
Is the oil pump drive gear in place and has intact teeth etc etc ???
Cool.
Buddha.
Quote from: Sandgroper57 on January 24, 2018, 05:16:05 AM
I would expect at least some oil to be pushed out of the oil switch hole even with shot mains.
Just putting this out there.. you didn't misplace the pin in the oil pump shaft? Or the gear isn't damaged as suggested by Grejet.
Fair bit of disassembly to check but clearly something isn't as it should be.
Well - i was thinking the same thing.
The pin is in the oil pump. And the gear is mint. I wonder - is it possible to put something together the wrong way so that oil pump gear from engine side is not spinning.
Quote from: The Buddha on January 24, 2018, 07:17:47 AM
Is the oil pump drive gear in place and has intact teeth etc etc ???
Cool.
Buddha.
Yes - oil pump in place. With gears, pin... its just annoying.
Has the gear on the back of the clutch been removed and replaced the wrong way around? I see there is a note in the manual which specifies the boss has to face the clutch. Should be fairly obvoius which way it goes though.
So if it is all assembled correctly, a blockage is looking likely.
FWIW, I have never had one these motors apart. Just going through the manual trying to work out what could go wrong. As I am sure you are as well.