GS550E 1980 engine leak Crankcase or where ?

[ukjules]

I have my old GS550E that for years has had an oil leak on the
left hand side, lower engine at the front. See pic.
The right hand side is as dry as a bone and always has been.
It is not the head gasket (I am sureish)
Engine is tuned correctly and doesn't smoke.

Now a few years ago on this very bike I went round Europe on it and it
had the same oil leak ! It has quite simply remained the same for years indeed since I bought it.
I have suffered it as I simply cannot find where it is or
with new gaskets solve it. But now with lock down i am mentally ready
to do whatever.

What i have done: (All bolts on bike torqued to correct settings)

-Renewed head gasket (many times) no change . We i reckon can discount this.
-Renewed alternator gasket (I always see slow seepage from one of the alternator casing bolts (highlighted))
-Renewed base gasket (Never used a genuine Suzuki one)
-installed gaskets with Wellseal and dry. Surfaces clean and flat.
-The base gasket should not be under pressure so how could it come out of area highlighted anyway ?
-I must also say I never have known if i have the right base gasket as many come with rubber o rings
that go in oil ways before the base.

-Gunked engine down and i could see slow seepage from one of the alternator casing bolts (highlighted)
But that surely couldn't produce the oil as per pic ?
After that I can never tell where the oil is coming from ?

(Amount oil used: say a 100m run it would go from full to half way down on measuring window)

gs engine leak small a.jpg

[Nessism]

Lots of members here have had success finding leaks by first degreasing (completely) and then spraying foot power on the affected area followed by starting the engine and watching closely.

[ukjules]

When you say spray .. you mean
"dust" the area with the talcum powder
like footpowder ?

I only ask as you can get aerosol foot stuff.....

I have tried powder a few years ago
to no success but will try again this week.

- What about a super soapy substance ?
something that would blow put bubbles ?
neat washing up liquid ?

[I'll run this thread to a fix and will
report success or failure]

[Rich82GS750TZ]

Yes, the aerosol powdered foot spray. On a clean dry engine. Spray every engine gasket seam, tensioner gasket, tachometer drive. May be better to have bike on center stand. Start it and watch for what gets wet.

[ukjules]

Understood. Will inform on result.

[Brendan W]

Are the screws the right lengths in the right holes.
There are three different ones, 35, 40 and 45mm.
A 40 in a 35 location can seem to tighten the gasket but it's actually bottoming out.

https://www.cmsnl.com/suzuki-gs550e-1980-t-e01-e02-e04-e18-e21-e22-e24-e25-e26-e30-e34_model13479/partslist/FIG-05.html

[ukjules]

Very good point .
I am convinced they are and have checked a few years ago.
Another check will be done though as I am sure
a few are helicouled due to stripped threads
but thankfully are at correct torque.

Q) on the alternator cover even if it was dribbling out
as seen when stopped surely it couldn't be the
main cause? The cover is not pressurised ?
or is it at high revs ?

b) the base gasket. if that had gone ... or
the cheap gaskets I use (and maybe in addition
the gasket set missing a rubber seal for oilways)
as it is not under pressure how could that cause
the oil leak ?

[Brendan W]

The crankcase is pressurised a bit depending on the amount of blowby gas at the rings.
It might be worth checking the condition of the scrubber pads at the breather cover on top or at least check that something is blowing out up there just to eliminate it.
Blocked breathers will eventually cause leaks.
For some unknown reason covers can become unflat. If the gasket is too thin it won't be able to tolerate the uneven surface. Maybe that's a difference between oem and others?
How much to top up after the 100 mile run?
At one stage I was losing a liter every two hundred miles. It was bubbling out the front of the headgasket and my left boot and leg were very wet and it dripped at lot when parked up.

[ukjules]

I reckon 200m cruising would need
1/2 l oil at least.
It hasnt seemed to get any worse !!!
has remained like this oil loss.

-spray powder bought and will clean
and use and report.
-will check breather too.

I am sure there might be an issue with the
base gasket and if / or the additional
seals are in or were even in kit.
I have never known where to get the
perfect correct gasket set for bottom
end up rebuild.
I suppose it is pay the cash to a Suzuki
dealer if they can get it.

firstly I wanna know where the hell
this is coming from

[Brendan W]

Last time I checked the oem base gasket was only a tenner-ish.

[ukjules]

You are right I found one for 14£
for hopefully my model at "Robinson
foundary" uk.

On the pic does o ring 6 (2 of)
goat front left and right I.e. where 4 is
pointing too ?

o ring 5 of course goes on piston mouths

20201103_073255.jpg

[Brendan W]

There is a seal ring that goes in that pear shaped hole.
The last kit I bought had a shaped ring.
The circular one will go there with a bit of help.
I would be inclined to fix it there with a tiny bit of 3 bond or similar.
That's the main oil riser to the head and you don't want it getting blocked.
There are enough distractions getting the barrel back on the pistons without having to wonder if that ring has jumped ship.

[ukjules]

If I take the barrels off I agree I gota be sure.
q) I am sure on the head gasket I have
put my cheapo ones on dry and with wellseal.
(gasket sealant). I almost think it's not necessary.

what's think put the base gasket on dry ?
or use with some gasket sealant ?
Same question for head gasket ?

It is the one area I have not been forensic
in noting down what iv done and what is best
from experience.

[ukjules]

Update: just noted 3 bond !! that looks the business
and will use on alternator cover plus gasket.

- about to do the spray powder oil leak testing.
will report later

[Brendan W]

I've got the grand total of one 850 under my belt.
I bought an NE engine set.
I coated the base gasket in high temperature aluminium paint because someone had gouged the deck a bit too much for my liking.
The pear shaped oil riser seals at the back corner of the base gasket had risen out of the gasket and were pinched. Were they originally circular? Who knows.
Compared to oem, the base gasket was tissue paper and I very nearly tore it getting the second pair of pistons in.
The headgasket went on dry apart from a bit of sealer to hold the chain tunnel seal in place.
I was very surprised at the amount I had to tighten the head bolts when checking the torque after the first few hundred miles.
Seem to recall is was close to a full turn.
I also had to open out the four outer holes in the head gasket because they were in the wrong place and the fire rings were not centered on the cylinder bores. Off by a mm or more.
The valve seals were rubbish or I screwed one or two of them up so I got a complete Athena replacement set.
That's over five years now and everything is dry as a bone.