Mystery Oil Leak

[jimvette999]

I've read the oil leak thread and any other threads I could find but none seem to give me an answer....please advise.

I've replaced the clutch rod seal thinking that was it since it's very close to the leaking area. That didn't work. First off-I degreased the area and when engine is running, that's when the leak occurs. There is no oil running down the sides of engine
It's not leaking at:
Neutral Safety Switch
Oil Pan
Shift Shaft
6 o'clock copper washer on side cover or cover itself
Air Box Tube - Air Box is dry
Wires from stator

The reason I know these aren't leaking is after it's been degreased and BEFORE I've riden on the road and blown oil around, these areas are still dry.

It drips onto the exhaust. It's up & under toward the center of underside of engine. It's very hard to see under there even when I tilt bike over onto one leg of center stand. If I could elevate entire bike off the ground a couple of feet I could track it down I think but just hoisting the front end up and running engine will starve it of oil. The leak is relatively small but I don't like any leaks.
Thanks for any suggestions you may have,
Jim

 

[maleko89]

How about the oil level switch? Also check the inboard mainfold bolts on the #2 and #3 cylinders. They go through to the oil passages. Feel around the valve cover gaskets too.

Mark
#1098

 

[jimvette999]

How about the oil level switch? Also check the inboard mainfold bolts on the #2 and #3 cylinders. They go through to the oil passages. Feel around the valve cover gaskets too.

Mark
#1098

Thanks Mark, I'll check these suggestions. The oil level switch is good. That's the one in the pan I believe. If the manifold and valve covers were leaking, wouldn't the oil be leaking down on the sides of motor or is there a passageway down the center of the block. I ask because I have no oil running down sides of engine at all.

Jim

 

[maxcruiser]

Maybe leaking where stator wires go through stator cover/engine block - Left front lower cover towards the back of it - hard to see accept from the bottom looking up.

Mike

 

[maleko89]

+1 to that. When my grommet went bad the oil travelled up the wire like a wick. You could try putting some Permatex Black where the wires go through and see if the problem goes away.

Mark
#1098

 

[one2dmax]

We actually ran into a problem last summer where a guys bike had a defective block. It actually had a pin hole in the case under the number 1 cylinder above the middle drive gear area.

He found it by using my "wet spot" suggestion. Clean the bike thoroughly and spread some baking soda or flour around the engine and start looking for the wet spot. Works on Fat Girls too.

Sean

 

[jimvette999]

Maybe leaking where stator wires go through stator cover/engine block - Left front lower cover towards the back of it - hard to see accept from the bottom looking up.

Mike

Mike, thank you. This leak is either directly above or to the right of the clutch pushrod, closer to the center of engine from what I can tell. It's as though the engine mating surfaces has sprung a leak which seems unlikely. If I could get the bike up higher, I believe I could actually see it leaking. By the time I see it, a drip has run down along the case and accumulates near a bolt head at about 3 o'clock from clutch rod. If/when I do find it, I'll be sure and let you guys know what it was.

Jim

 

[jimvette999]

We actually ran into a problem last summer where a guys bike had a defective block. It actually had a pin hole in the case under the number 1 cylinder above the middle drive gear area.

He found it by using my "wet spot" suggestion. Clean the bike thoroughly and spread some baking soda or flour around the engine and start looking for the wet spot. Works on Fat Girls too.

Sean

Thanks Sean. This leak is relatively new (6 months) would that make sense? I've owned the bike since new. I may have to employ the "fat girl" trick :th_love031:

 

[gleno]

Mike, thank you. This leak is either directly above or to the right of the clutch pushrod, closer to the center of engine from what I can tell. It's as though the engine mating surfaces has sprung a leak which seems unlikely. If I could get the bike up higher, I believe I could actually see it leaking. By the time I see it, a drip has run down along the case and accumulates near a bolt head at about 3 o'clock from clutch rod. If/when I do find it, I'll be sure and let you guys know what it was.

Jim

Hi Jim,

I responded to a thread you started titled “SDF Seal? Please help” because I was having the exact problem you have described.

I also replaced the clutch push rod oil seal and thought I had done a good job and that an oil leak from the same place would be impossible.

Wrong.

For those unfamiliar with this oil seal, it is the external oil seal for the clutch push rod and it's under the clutch slave cylinder.

This is what I wrote at the time.

“Once its out you have to clean the rubbish out of the space you just removed it from. Use a suitable solvent to remove dirt and oil from the seal cavity. Old sealant may require you to use a scraper or fine brush but be careful not to scratch the seal seat in the cases. The cleaner the cases, the easier the new seal will seat in.

Sean is right. Clean (and polish) the push rod to remove any burrs, scratches or corrosion from the shaft.

When these are clean, you can apply a sealer which Yamaha sell or something like a Loctite sealer. I didn’t use a sealer and it sealed just fine.

When you put the new seal in you should use a suitable drift to press or tap the seal in into its seat. Make sure the drift is perpendicular to the seal and use light force. You do not want to bend the metal substrate of the seal. Check it as you go to see that it is going in evenly. If one side is high, tap it down lightly until it is even, before proceeding further.

I left the push rod in place, oiled the seal with engine oil, placed it over the push rod and pressed it to the seat in the case. I then put a metal washer on the push rod, pushed the washer down onto the face of the lightly seated seal and used a tube spanner as a drift to lightly tap the oil seal into its seat. Worked like a charm.”

HOWEVER, this story has a sequel which I forgot to post.

The seal achieves its sealing ability in two ways.

1) By pressing its outer circumference against the inner circumference of the recess in the crankcase.

2) By pressing a ridged flange, on the side of the seal facing the crankcase, hard against the crankcase.

The second is very important. This facing edge provides the pressure seal and stops oil being ‘pumped’ out of the case to the two inner shaft flanges of the seal, which scavenge oil off the moving shaft.

If you used a drift to seat the shaft you may not have achieved a proper pressure seal against the case. You should check to see that it is firmly seated against the case. If it is, the external face of the seal will not protrude beyond the surface of the crankcase at all. It will be flush (or slightly recessed) with the crankcase surface but it must be firmly seated.

How do I know this?

The first time a fitted this seal I had exactly the same problem. After a couple of days it started to leak slightly and tracked onto the left header pipe just before the junction to the rear muffler before spotting on the garage floor.

I removed the middle gear cover and the oil had tracked to various points on the case (bolt heads etc). Heat and wind spread a little oil a long way.

I removed the clutch slave cylinder and when I checked the seal, it was protruding very slightly above the level of the case. I used the drift and seated it firmly into its recess. End of problem.

Don’t be surprised if you get some minor oil leakage onto the exhaust after you fix the seal because the oil has probably soaked into the insulating material behind the middle gear cover and it will drain for a day or two unless you clean it off.


Hope this helps :thumbs up:

 

[jimvette999]

EXCERPT of gleno's reply

Hi Jim,

I responded to a thread you started titled “SDF Seal? Please help” because..............

Thanks for responding gleno. I used info from your other post to fix the seal (I thought) and I appreciate your follow up information. That might explain why I still have a leak. I was perhaps to careful not to over do the tapping in of the seal and I'll have to see if I did as you did and not fully seat it. Unfortunately, the oil ruins the slave dust boot and I'll have to order another. Swells it out of shape.
You guys are great, thanks to all that have responded to my threads.
Jim :cheers:

 

[jimvette999]

Well, I found the leak. It's where the case halves meet just to the right of clutch pushrod seal. I ended up removing the cover by the foot shifter and putting it back on after I removed the clutch slave so I could start bike and observe where the leak was coming from. I was surprised to see the clutch pushrod was pushed out against the cover when started.

Should I have crank case pressure? I thought it was vented to the air box? :hmmm:

Anyway, I cleaned the area that was leaking with brake clean and blew it dry and used Permatex RTV grey on it. I hope it seals but I have my doubts. I'm not pulling the engine out to fix that leak. I hate leaks!

Any comments on the crank case pressure or the cause of the clutch pushrod protrusion?:ummm:

I'm also putting the fork seals in.


Thanks,
Jim