Is there a way?

Hegel · Oct 6, 2014

Another question for you clever fellows

Is there a way of fixing an oil leak in the crank cases, other than taking the engine out and tearing it down again?

I say this as I put the oil in the bike this w/e, in prep' for starting...Only to find there's a slow drippy leak from the bottom of the CC's

It's right by the bottom bolt.

The engine was professionally rebuilt.

Cheers,

Steve

Torontonian · Oct 6, 2014

Lucky you, so much for the pros. A crankcase reed type beather works wonders to keep the oil in. Other than that you could clean the area really well Methyl Ethyl Ketone final ' then apply some of Hobot's favorite product JB Weld. Good luck. :|

WZ507 · Oct 6, 2014

Torontonian said:
Lucky you, so much for the pros. A crankcase reed type beather works wonders to keep the oil in. Other than that you could clean the area really well Methyl Ethyl Ketone final ' then apply some of Hobot's favorite product JB Weld. Good luck. :|

All sound advice above. In the alternative.....

I've had excellent luck sealing similar leaks with a 2-part urethane adhesive from 3M - Ultraflex.
http://tinyurl.com/qzgrt6x

It cures very quickly (5-10 min tack-free time), is flexible and adheres tenaciously to a wide range of properly prepared surfaces. In your case the key to success with any adhesive is to get the surface absolutely free of any trace oil residue, and keep it that way until the adhesive is cured. If the subject case area is weeping perpetually it will be challenging to get good adhesion in that area.

Another option is 3M DP-920, a 2-part epoxy adhesive formulated specifically for oily metal adhesion (typically for bonding sheet metal that has light processing oil on it from the steel mill where it was rolled).
http://tinyurl.com/l8gmxxn

This adhesive would not be flexible, but then again on an engine case it would not need to be flexible. As above, get out the acetone, MEK or toluene and clean, clean, clean, and clean again - the cleaner the surface the higher the probability of success.

Hobot · Oct 6, 2014

hobot would not advise JBW seal unless there is a case crack so would follow above advise to try to get a layer of some miracle smear on or spray on sealer over seam and hope that' actually where the oil is coming from. MIght try some aluminum duct tape to see if that stops leak for a time to know where to actaully patch as may be drooling down from more than one leak. TV ads showed some spray on stuff that sealed water hoses and plastic containers and roof and plumbing drains, which I was gonna try this year on Trixie that only leaked if I when faster than a gramma on valium. JBW is not a very good adhesive and is very brittle in thin layers. Might glue a cloth tape strip to get some fiber back up and sealant thickness to hold a rider or two. In the end like me most likely will have to tear down completely and work back up with organic thread and favorite sealant. I've lost a year of Cdo ridding d/t too many other priorities to finish Trixie tear down - as I'm not set up well to be a mechanic, so may have to farm yours out to someone less professionally $tressed, but has tools time and interest.

https://www.google.com/?gws_rd=ssl#q=sp ... %20sealant

Hegel · Oct 6, 2014

Thanks for the tips

When I get a mo (most likely this w/e) I'll degrease and see if I can pin point where the heck it's coming from.

AFAIK the cases are good. When I initially got them, I bolted them together with some wellseal, just to find out if they were oil tight. I dropped a couple of pints into them, they didn't leak.

Thanks guys!

S

WZ507 · Oct 6, 2014

One other thought regarding adhesives. Aquaseal is a viscous 1-part adhesive that is slow curing (24+ hr) but also adheres well to a variety of surfaces and when cured is a really tough elastomer. This is an excellent alternative to Ultra-Flex.

https://www.mcnett.com/gearaid/aquaseal#10110

And to amplify on what hobot said…. be sure you know the exact location that the leak is coming from - not necessarily where it is dripping from. To make such a determination requires serious determination on your part. Clean the entire area scrupulously so no trace of oil and no shiny hint of anything is present. Then camp out down there with your flashlight and watch for that 1st hint of shiny reflection where oil is sneaking out of the seam. Then quickly wipe it away, keeping the vigil to see if anything else is coming anywhere else. Hopefully you won't have to watch for hours, but you never know.

With a good breather system on the engine you should win this one with a sealant. Without a good breather, the crankcase may pressurize and be too much force for the sealant to hold back at elevated temperature. Good luck and let us know how you make out.

PeterJoe · Oct 6, 2014

Many years ago I heard of people fixing leaks on the crankcases of their aircraft engines by using a Shop Vacuum cleaner:

1. The first thing that you do is to use the exhaust side of the vacuum cleaner to pressurize the crankcase. Make sure that the air is filtered before entering the crankcase. Now you can find the leaks by using soapy water.

2. Once you have determined where the leaks are, use the vacuum side of the vacuum cleaner and suck the air out of the crankcase thus creating a low air pressure.

3. While the vacuum cleaner is on, apply solvent over the area where the leaks are. Supposedly the solvent will clean that area out between the case halves.

4. After solvent cleaning the case halves and while the vacuum cleaner is on, apply a diluted sealant over the leak area. Supposedly the sealant will also be drawn inwards.

5. Finally let the sealant take a set

I have never done this, only heard that it works so you can take it for all its worth.

Deets55 · Oct 6, 2014

Never tried this myself, but I read somewhere to de-grease the entire suspect area and then cover with baby (talcum) power. You should be able to pin point the leak from the damp spot.

Bob Z. · Oct 6, 2014

What is the sealant type that is now in place and leaking? Ask the re-builder.

Long ago I put together a set using clear silicon sealant. The dripping fuel from the carbs quickly created an oil leak right behind the cylinders. Silicon and fuel is no good.

Sealing one leak area may just force a leak somewhere else; the path of least resistance.

Another potentially bad application for silicon sealant is the inlet valve rocker cover. If an excess string of sealant gets down into the oil drain hole near the right side valve spring cup, big problem.

ML · Oct 6, 2014

Had a similar problem after a re-build. Turned out to be a loose crankcase bolt up near the front Iso. Leak gone.

Torontonian · Oct 6, 2014

Yeah just re-tighten. :|

DogT · Oct 6, 2014

Good Luck. That shop vac procedure sounds like it may be the best bet, I may even try that, I've got a weep in my cases too which has been aggravated with syn 20W50 instead of SAE50. I really don't want to break it apart. The problem is going to be how to seal the shop vac to CC and where to attach it, valve cover?

kerinorton · Oct 6, 2014

hobot said:
hobot would not advise JBW seal unless there is a case crack so would follow above advise to try to get a layer of some miracle smear on or spray on sealer over seam and hope that' actually where the oil is coming from. MIght try some aluminum duct tape to see if that stops leak for a time to know where to actaully patch as may be drooling down from more than one leak. TV ads showed some spray on stuff that sealed water hoses and plastic containers and roof and plumbing drains, which I was gonna try this year on Trixie that only leaked if I when faster than a gramma on valium. JBW is not a very good adhesive and is very brittle in thin layers. Might glue a cloth tape strip to get some fiber back up and sealant thickness to hold a rider or two. In the end like me most likely will have to tear down completely and work back up with organic thread and favorite sealant. I've lost a year of Cdo ridding d/t too many other priorities to finish Trixie tear down - as I'm not set up well to be a mechanic, so may have to farm yours out to someone less professionally $tressed, but has tools time and interest.

https://www.google.com/?gws_rd=ssl#q=sp ... %20sealant

Hey Hobot, you asked me if you could split the cases and left the rhs case intact. Is that because you have tried all the above and it doesn't work. Sealing the cases when they are split sure does though.
Dereck

kerinorton · Oct 6, 2014

DogT said:
Good Luck. That shop vac procedure sounds like it may be the best bet, I may even try that, I've got a weep in my cases too which has been aggravated with syn 20W50 instead of SAE50. I really don't want to break it apart. The problem is going to be how to seal the shop vac to CC and where to attach it, valve cover?

Breather.

WZ507 · Oct 6, 2014

PeterJoe said:
Many years ago I heard of people fixing leaks on the crankcases of their aircraft engines by using a Shop Vacuum cleaner:

1. The first thing that you do is to use the exhaust side of the vacuum cleaner to pressurize the crankcase. Make sure that the air is filtered before entering the crankcase. Now you can find the leaks by using soapy water.

2. Once you have determined where the leaks are, use the vacuum side of the vacuum cleaner and suck the air out of the crankcase thus creating a low air pressure.

3. While the vacuum cleaner is on, apply solvent over the area where the leaks are. Supposedly the solvent will clean that area out between the case halves.

4. After solvent cleaning the case halves and while the vacuum cleaner is on, apply a diluted sealant over the leak area. Supposedly the sealant will also be drawn inwards.

5. Finally let the sealant take a set

I have never done this, only heard that it works so you can take it for all its worth.

Just be sure you don't make a solvent bomb out of your vacuum cleaner canister in the process! I can just see someone with a large leak using lots of solvent and BOOM!

kerinorton · Oct 6, 2014

DogT said:
Good Luck. That shop vac procedure sounds like it may be the best bet, I may even try that, I've got a weep in my cases too which has been aggravated with syn 20W50 instead of SAE50. I really don't want to break it apart. The problem is going to be how to seal the shop vac to CC and where to attach it, valve cover?

Breather. but don't suck too much of the cleaner into the vacuum cleaner.

Remember the song. 3 sticks of Dynamite sitting on the wall. One scitk flel, now te'hres no fnkcuig dtinyamae and no fiunkcg wlal.

Dereck

Dean · Oct 6, 2014

Deets55 said:
Never tried this myself, but I read somewhere to de-grease the entire suspect area and then cover with baby (talcum) power. You should be able to pin point the leak from the damp spot.

Have used this technique a lot on aircraft engines. We use dye penetrant developer. It's like fine talc suspended in a solvent. Spray it on and the solvent evaporates and leaves a nice thin even coating of talc. Makes finding where the leak is coming from very easy.

Hegel · Oct 7, 2014

Bob,

Not sure who makes the sealant, tho after a conversation with the guy yesterday, a tube of "black sh1t" is 12 quid. So I'll be making a trip over there.

I meant to get into the shop yesterday, check the bike, but by the time I got home from work it was pitch dark (I don't have any power in there), so not a good time to go hunting for leaks.

The technique for finding leaks on aircraft engines sounds great. Was there ever a pressure gauge on the thing? I say this I've got an all but useless Vax and a redundant manometer...mmmmm

olChris · Oct 7, 2014

Apart from all the above fixes, maybe ask your self "why" is oil appearing ???????? in that area.. It shouldnt be there in excess.

If the bike is stationary and cold it should have minimal oil in sump, (depending on oil pump scavanging ability..) Unless it has the typical wet sumping symptom

When is it leaking, whilst running ?????

After you have been for a ride and stopped, then leaks ????

All the time???

Do you have a "shut off" valve fitted to oil inlet line????

Are you really really really.... sure that the leak is not further above.. ie, rocker cover gaskets, rocker pivot plate gaskets..

Hegel · Oct 8, 2014

Hi Chris,

The bike hasn't been started yet, I put the oil in mostly to see if there was anywhere it'd leak out again. There might be oil sitting in the sump, again, I've got to have a better look @ the w/e. I did get a quick look last night, is definitely leaking out (albeit a very small amount), at where the bottom bolt is. It might well be that all I need to do it an extra nip up...But I'll get some sealant, etc to make doubly sure.

I was more worried about having to pull the lump out again to fix it. But thanks to the above doesn't sound like it, whew!

Actually...When you're prepping for a first start would it be advisable to disconnect a rocker line, kick it through a few times to make sure that the oil is in fact reaching the rockers?

Cheers,

Steve

Is there a way?

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