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**tkent02** · 01-25-2009, 12:51 PM

The Suzuki Service manual has this picture for the GS 750, do you have this for your bike?
Free download from cliff's website if you don't.

**TheBigRed** · 01-25-2009, 04:34 PM

Originally posted by tkent02 View Post

The Suzuki Service manual has this picture for the GS 750, do you have this for your bike?
Free download from cliff's website if you don't.

I do have the service manual, though it ends in 80 and my bike is an 81, but for the most part the engines are the same between those years, it wasn't till 82 or 83 that they went under any major changes. I also have the one downloaded from basscliff's site and have that for refference, which actually does cover the 81 year as well.

Amos

**renobruce** · 01-25-2009, 05:17 PM

How was the oil pressure checked? What were your readings? There isn't much pressure to begin with. If you haven't already, remove the oil galley bolt and turn the engine over. Oil should shoot out (have a rag ready).

Oil pumps don't normally fail completely. They can loose their efficiency however. If the two orings behind the pump go bad, it can cause the pump to not work very well.

**TheBigRed** · 01-25-2009, 05:26 PM

Originally posted by renobruce View Post

How was the oil pressure checked? What were your readings? There isn't much pressure to begin with. If you haven't already, remove the oil galley bolt and turn the engine over. Oil should shoot out (have a rag ready).

Oil pumps don't normally fail completely. They can loose their efficiency however. If the two orings behind the pump go bad, it can cause the pump to not work very well.

No pressure readings, but the builder did do the second of removing the galley bolt and it was bone dry.

As stated have no real idea of the status of the oil pump in there, so I'm planning on replacing it outright this point, but also would like to verify it isn't just a blockage somewhere as well.

Good point on the o rings, and as stated the oil pump was still installed in the lower end and wasn't removed to be inspected, so they may very well be shot as well, which will be addressed in replacing the pump as well.

Amos

**renobruce** · 01-25-2009, 05:31 PM

Oil light stay on? Just a thought, but you could also check the oil pressure switch to make sure it's not stuck down. It needs to go up in order to get oil to flow to the galley (I think).

**tkent02** · 01-25-2009, 06:40 PM

Are you certain all the little gears and gizmos behind the clutch that drive the pump are installed correctly?

**Nessism** · 01-25-2009, 08:32 PM

Oil pumps are almost foolproof; as Bruce stated, it may get worn but will not fail outright. Most likely the pump drive mechanism is broken in some way. There are a couple of gears and a roll pin, maybe something broke loose.

Good luck and hope you caught the problem in time!

**TheBigRed** · 01-25-2009, 09:36 PM

Originally posted by Nessism View Post

Oil pumps are almost foolproof; as Bruce stated, it may get worn but will not fail outright. Most likely the pump drive mechanism is broken in some way. There are a couple of gears and a roll pin, maybe something broke loose.

Good luck and hope you caught the problem in time!

Definately caught in time, as the engine was completely just built up top end up, and the bike has only fired a few times (long enough to realize the oil pressure issue).

I'll be checking all those little gears and gizmo's behind the clutch when I go in to replace it anyway, so if there is a problem there, I'm sure I'll catch it when putting in the pump from my original engine.

Renobruce, I had thought of checking the pressure switch, and will definitely be sure to check it as well now, as I have a couple spares of that part as well. (The wonder of having spare engines....)

Amos

**Nessism** · 01-26-2009, 10:02 AM

I suggest you check the pump that is in there now so you can determine what is wrong. If you just start changing parts all willy nelly, you may not fix the problem.

**TheBigRed** · 01-26-2009, 10:55 AM

Originally posted by Nessism View Post

I suggest you check the pump that is in there now so you can determine what is wrong. If you just start changing parts all willy nelly, you may not fix the problem.

That is pretty much the plan.. Sort of.. I actually have 3 engines in pieces that we used to build one, so I'm not going to be having to buy the pump that I'm going to drop in. Just need some time to do it. This week is pretty much shot, as is most of next week. I need to check with the wife and see what is on our calendar for the first Saturday in February, as that may be the first chance I get to work on it.

I think I'm going to check the measurements on the pump I pulled from my original engine in the meantime to make sure it is in spec, then I can just put it in knowing it is in good condition.

I'm also thinking of pushing some small guage wire down all the oil passages I can get access to with the clutch cover and oil filter out to check and make sure there aren't any blockages. I have the case halves from my parts engines that I should be able to use to figure out how far the wire should go before hitting any bends etc.

Amos

**Suzuki_Don** · 01-26-2009, 10:44 PM

The oil system works as follows. The oil is picked up from the sump by the oil pickup though a sump filter screen. It is drawn up into the pump and then pumped into the oil filter. From the oil filter it is then pumped to the pressure switch from where it is distributed to the rear oil gallery and the transmission.

If there is no oil at the rear oil gallery then it has to be one of the following items. Oil not being picked up from sump (no oil in sump, oil screen in pickup clogged, "O" ring between crankcase halves damaged or missing, "O" rings sealing oil pump to engine damaged or missing). Oil pump failure. Clogged or defective oil filter (you have replaced the filter haven't you). If you are going to check out the oil passages you will have to remove the oil filter, as there are two large passages leading to the oil filter.

Hope these suggestions are helpful.

**TheBigRed** · 01-27-2009, 09:40 AM

Originally posted by Suzuki_Don View Post

The oil system works as follows. The oil is picked up from the sump by the oil pickup though a sump filter screen. It is drawn up into the pump and then pumped into the oil filter. From the oil filter it is then pumped to the pressure switch from where it is distributed to the rear oil gallery and the transmission.

If there is no oil at the rear oil gallery then it has to be one of the following items. Oil not being picked up from sump (no oil in sump, oil screen in pickup clogged, "O" ring between crankcase halves damaged or missing, "O" rings sealing oil pump to engine damaged or missing). Oil pump failure. Clogged or defective oil filter (you have replaced the filter haven't you). If you are going to check out the oil passages you will have to remove the oil filter, as there are two large passages leading to the oil filter.

Hope these suggestions are helpful.

Very, very helpful. Now I know the oil flow path and can start troubleshooting by following it. I am going to check the oil filter to see if oil has made it there (simple enough to check). If it isn't making it there then I can start tracing it back.

Hopefully it isn't the O ring between the cases, as that would be a PAIN to replace after all the work that has already been done. It could be the other O rings or the pump. Like I said, now knowing the direction and path of oil flow will help considerably.

Amos

**TheBigRed** · 02-16-2009, 02:35 PM

Originally posted by tkent02 View Post

Are you certain all the little gears and gizmos behind the clutch that drive the pump are installed correctly?

Originally posted by Nessism View Post

Oil pumps are almost foolproof; as Bruce stated, it may get worn but will not fail outright. Most likely the pump drive mechanism is broken in some way. There are a couple of gears and a roll pin, maybe something broke loose.

Good luck and hope you caught the problem in time!

Ok, Tkent02 you get the prize...

Friday afternoon we dug into it. Sure enough the oil pump drive gear that sits behind the clutch didn't get installed. Builder thinks I may not have had the little baggie with it in when he was putting it all together and that is why it got missed. I'm not sure on that, but anyway, we did get it installed now and sure enough, we have oil pressure.

And Ness, as stated before, the builder was smart enough to not run the engine for more than a few seconds when he realized there was no pressure, and before cranking on it again, we dropped a few ounces of Oil down each cylinder to keep things lubed til pressure built up.

However, Now I've lost spark (pretty sure I know where to look on this issue as the only other change to the bike between his place and mine was replacing the headlight glass with the proper glass that attaches to the bucket with two bolts and has the screw adjuster for aiming it. Which puts the "glass" about 1/4 inch further into the headlight bucket which I've figured is where I"m loosing spark as Saturday with the headlight out I managed to get the bike running). All that to say, I probably won't start a thread on it as I'm pretty sure I know where the problem lies.

Anyway, all this just to say, when re-installing the clutch basket etc, make sure the gear that drives the oil pump is there.

Amos

**Suzuki_Don** · 02-16-2009, 03:46 PM

Amos. Glad you got it sorted. It's a good looking bike. You can enjoy it now when you get your sparks fixed up.

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