Small oil leak on cooling fins

[PimpS]

ok, then from the up left screw hole...

[OldNTired]

Originally Posted by PimpS

ok, then from the up left screw hole...

I would love to help, but now I am just more confused. What screw hole? Please, either find the part in the manual and tell me what it is,
OR post just ONE pic that shows the bolt.
There is one bolt on top of the engine cover that has a rubber gasket. Maybe the gasket is loose or bad.
There are two bolts coming down from the engine, one in front and one in back;
they are UNDER the cyl head. The front one is between the exhaust ports, the back one is under the intake port. These are cyl head bolts, and the nuts should be torqued to 7 ft-lb
(screw the metric!!!).
If it is not one of these, then tell or show us which one you mean.

[rynr]

Originally Posted by alantf

Can you clarify what you mean by tachometer. I think you've used the wrong word. A tachometer is a rev counter, which the GZ doesn't have.

True, but GN250 has a tachometer and the same engine. I don't really know how it's made in earlier Japan-made GZ250 (1999-2003) but in older GZ125 there's a plugged tachometer hole. In some GZ250 bikes it could be done the same way. In my 250 hole is molded (i mean that there's the same shape but there's no hole anymore).


PimpS - send us some pictures, maybe we will be able to help. And see part names in parts manual to avoid missunderstanding.

[PimpS]

Rynr, believe it or not, i was writing you a pm to clarify this, but i was feeling too much annoying with myself.

From checking the construction picture (cylinder with a pointed spot of possible leak) of cylinder:



But going through my pics, I think that the cylinder head got a leak; check it... The bolt on some pics is the one pointed in schematics. I'm sure you old geezers know that...











The oil leakage, after first finding and cleaning and 1500 km made, increased, judging by the oil drops on fins.

Thanks for your ideas and possible solutions...

PimpS

[rynr]

In my GZ 250 it looked similiar.

I believe that the leak is here. You can try to tighten cylinder head bolts, but don't turn them more than 12 Nm. It didn't help my GZ and propably won't help yours. You propably will be forced to disassembly cylinder head as you can see in one of my photos on page 2. That's only my predictions, so try to confirm this first by cleaning and looking what's hapenning when engine is running in the area I marked .

[PimpS]

Ok, thanks a lot.

[PimpS]

Rynr, i was in a hurry. Again thanks for advice. I've seen that in your case you used a seal paste... Tell me something: you propably took down the engine, to fix it? How long did it took to fix that? I believe when doing that i should be careful, cause if my memory serves me good, the head bolts are different in size and should be careful with no mixing them, when put together again...

Thanks for reply!

Drive safe!

PimpS

[OldNTired]

Originally Posted by PimpS

Rynr, i was in a hurry. Again thanks for advice. I've seen that in your case you used a seal paste... Tell me something: you propably took down the engine, to fix it? How long did it took to fix that? I believe when doing that i should be careful, cause if my memory serves me good, the head bolts are different in size and should be careful with no mixing them, when put together again...

Thanks for reply!

Drive safe!

PimpS

Yes, your memory is good, and you are right.
That kind of mistake cost me a bit of time; I 'assumed' they were all the same length and
started pulling them out and throwing them in a bag. It is an easy enough mistake to
recover from, but it is time wasted.
One thing you will want to know: the topmost cyl head cover bolt can not be removed while the cover is sitting flush on top of the cyl.
I just completely loosend it, then tilted the cover while I removed the bolt.
And do the opposite when replecing the cover.
If anyone has a better way, let me know.
I can't remember how long it took to remove it all, but it only took a bit over an hour (an hour and a half at most) to replace the head gasket, put sealer on the cover, bolt it together, and set the valves.

[PimpS]

Thank you Ol'n'T!

[rynr]

My friend actually did the most of the work, because i'd rather help someone who's experienced with engine fixing than doing it myself for first time . We did it 2 maybe 3 hours. I suggest to do it with someone experienced who knows what to do.

Engine doesn't have to be taken off, just take away cylinder head-to-frame mounting (triangles with holes), and some obvious things like a tank, chrome head covers etc. As OldNTired said head bolts aren't all the same, but not everyone is other than rest, maybe you will remember which is which . One of them has a washer that should be replaced. There are 2 head bolts under valve caps too. Oh, and about this one bolt - as OldNTired said, you have to place it in cover before you'll put it on engine.

Most of the time is taken by cleaning head to get rid of the old paste (cleaning). Don't scratch it with screwdriver or something sharp . There's also an round plastic camshaft sealer that is needed to be cleaned too. After sealing everything you'll have to wait until it gets harder (to start the bike). Time length depends on type of sealing paste you're going to use. It usually takes couple of hours to get hard.

Engine could work a little different in first minutes after first start, but after them it should work normally. Maybe you'll experience slight power increase and better (healthier) engine sound.

PS. This repair is great occasion to look how camshaft and chain looks like. When my ex-GZ125 had been sealing (don't know if i used correct form ) it also came out that camshaft chain need to be replaced.