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Left-Side Crankcase Leakin' Oil Like A Sieve

11K views 22 replies 13 participants last post by  Timmah6859 
#1 ·
So, the title pretty much says it all, but allow me to elaborate...

This is not a new leak. I've had Thunder for about two years now, and she's been leaking for at least a year and a half. Since she's been called back into service, it has gotten worse, little by little. We've put in Stop Leak and it didn't even touch it. Thought the crankcase cover may be loose, so Doomsday attempted to tighten the bolts today (cause, yanno, he's stronger n' me and all)...

...and discovered at least one bolt had been stripped previously. The tightening seemed to have just made things worse; she seems to be leaking twice the amount of oil now. I'm thinking it's the gasket, as there has also been little bits of rubber protruding from the crankcase for some time, but I am not confident enough in my mechanical prowess to attempt a repair myself. So, can any of you fellas tell me, what year I need to ask for when I go order this gasket and what size bolt I'll need? Yes, I will order a pair; if one sides' shot, I'm sure they both are. I know a very good mechanic that has worked on two of our Kawis before, and he's close to our place. She'll be in good hands until I learn what I need to and flesh out my toolkit more completely.

Or, if you guys have another suggestion or know what else may be causing this problem, please let me know. I know many of you have been wrenching on these beasties for a long time and I trust your knowledge. Thank you for any insight you can impart! :beerchug:
 
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#2 ·
Would that be the side the clutch cover is on? Is it just the clutch cover or is it the whole side? I use this website http://www.kawasakipartshouse.com/oemparts/a/kaw/50a69ca4f870021678c64582/engine-cover
to get part numbers and then I go to my local kawasaki place to order. But I did use a cereal box with great success on a smaller gasket, and although I am a girl and only been wrenching on this bike, I feel able because of all the help here and the great video that roach did on how to assemble the engine.
 
#3 ·
Would that be the side the clutch cover is on? Is it just the clutch cover or is it the whole side? I use this website http://www.kawasakipartshouse.com/oemparts/a/kaw/50a69ca4f870021678c64582/engine-cover
to get part numbers and then I go to my local kawasaki place to order. But I did use a cereal box with great success on a smaller gasket, and although I am a girl and only been wrenching on this bike, I feel able because of all the help here and the great video that roach did on how to assemble the engine.
Madame's leak is on the left side (as you sit on the bike), Stator/Damper Cam Gear side.
The clutch is on the right side.
:smiley_th
 
#5 ·
We've put in Stop Leak and it didn't even touch it.
I never use that stuff (anymore). Sometimes it stops the leak, sometimes it stops up more than the leak. you may have clogged one of the tiny oil lines and in turn increased oil pressure causing the leak to worsen. Used it in my first car radiator, 1973 Maverick (Grabber cause I was cool:rockon:). had to back blow the heater core cause of that stuff. Easy fix but it I was cold for a few days and had to replaced the radiator anyway. I suggest you blow out the oil lines when it's apart. Also, tightening bolts past the torque spec risks stripping it as well as other problems depending on which bolt it is.
Good luck - hope you get 'er back on the road soon!
 
#6 ·
Doesn't matter what year you ask for because they are all the same. Most just ask for 2006 because dealerships will hassle you if your bike is more than 10 years old. That being said, for your stripped out bolt I'd suggest putting in a helicoil or re-tapping the next largest size (helicoil is a better fix IMHO because you gain structural integrity).
 
#9 ·
Doesn't matter what year you ask for because they are all the same. Most just ask for 2006 because dealerships will hassle you if your bike is more than 10 years old. That being said, for your stripped out bolt I'd suggest putting in a helicoil or re-tapping the next largest size (helicoil is a better fix IMHO because you gain structural integrity).
x2

:smiley_th
 
#7 ·
I believe that the gaskets will be the same for all of the 750's. As far as the bolt? Depends on whether the bolt or the hole was stripped (most likely the hole...aluminum case vs steel bolt). If its the hole, you may be able to get away with packing it with jbweld and re-tapping it. If its the bolt, you can try chasing the threads with a tap and replace the bolt. Stock bolts for the case are 6mm-1.00 (the tap is the same size regardless of which way you have to go). The length will most likely vary, but you can get a replacement at a hardware store, just take the original with you to compare.

Over torqeing the bolts will cause the gaskets to bulge and possibly fail. Try to follow manufacturers recommendations when it goes back together.

Sent from Motorcycle.com Free App
 
#8 ·
... there has also been little bits of rubber protruding from the crankcase for some time,...
Could it be leaking from the outer stator cover? That cover does have a rubber o-ring type gasket. This would mean only three screws to replace that gasket, without pulling the engine off the frame.

Otherwise the rubber must mean someone has re-sealed the inner stator cover and used silicone at some point.

If you get the inner stator cover gasket done, you should also replace the shifter shaft seal, for a few bucks more.
 
#10 ·
Haha, waking up to so many answers about this, I feel like a kid at Christmas! At least it sounds like it'll be an easy enough fix...though now I'm feeling that the Stop Leak was a real derp move. :doh: Could one hand-tighten the bolts past factory specs? I don't have an impact wrench or anything; it was all done with manual hand tools.

Thank you guys (and gal; Bee, you ROCK! Needs to be more girls riding AND working on bikes, IMO!) for all the answers thus far; gives me a good jumping-off point! :D
 
#11 ·
Never Use An Impact on Those Bolts

No, no. Never use an impact tool on those bolts. The torque spec is only in the inch/pound scale (easily converted to foot/pound).

The specific torque number should be in the downloadable repair manual and here's a sticky post with some of the numbers. The covers aren't listed there, but at the top there's a guide to use by bolt size.

http://www.vn750.com/forum/showthread.php?t=28793
 
#12 ·
Doom said the bolt was spinning pretty freely when he tried to tighten it. So, we're gonna grab some gaskets and Helicoil for the beastie. As far as the Stop Leak goes...is there any effective way to flush it without breaking everything down? I just changed my oil and filter about a week ago. Thanks again for the help!
 
#13 ·
All I know is what I've done to a couple of cars in the past that were full of sludge (it did work and didn't damage it...), but the haters will probably scream when I say what it is:

Drain the oil, fill with diesel, run (idle only) it for a couple of minutes, drain the diesel, refill with oil. It will probably make some noise, but you have to get it circulated to clear all that crap out of the internal passages. If it starts knocking, shut down immediately.

There are commercial engine flushes out there as well, but my best experience has been with diesel.
 
#14 ·
If you are changing the gasket between the main stator cover (not the smaller one with the o-ring seal and only three screws) you need to loctite seal the bolt that screws through into the front cylinder cam chain area. It is in the manual, but easy to forget. Also, I found, when rebuilding my 1985 engine that the bolts did not go very far into the threaded part of the case and countless previous owners spannerings had weakened the threads to the point that quite few of them would not hold even the factory torque settings. I had to helicoil more than one. I replaced the stock bolts with ones a little longer and also cleaned all the threads with a tap, and checked that the bolts I had would be a good match length-wise for the now cleaned out threads. It then all went back together well and torqued up correctly with no leaks, plus I know I can take the cover off again if needed with out any worries.
 
#15 ·
hey ...just curious if running Seafoam in the case would do the same as cleaning with diesel.

I would think it would be safe to do since you are going to drain it anyway. I never used diesel in place of oil...I would think Seafoam in the oil would be safer...no?
 
#16 ·
Nothing personal Jak, but I would never run any engine with diesel fuel in place of the oil. I might disable the ignition or fuel and spin it over enough to circulate the oiling system, but not run it at all. We tend to freak out a bit when we find the oil simply contaminated a little with gas.

I would think an oil/filter change, along with a proper dose of Seafoam, Marvel Mystery Oil, etc., would be enough. Then maybe change oil next time a bit early.

I just now added a bit of Marvel Mystery Oil to the last 1000 miles of this oil change on my bike, trying to ward off a sticky valve, and the oil light has been flickering on briefly on some startups. I'm hoping it's just a wonky oil sender. Next time will probably be Seafoam instead, I just had the MMO sitting around for air tools.

Jak, in the past I've gone at engines with a putty knife and shop-vac, the sludge was that bad. In one case, it was built up so hard it was slowing movement of the pushrods. Even had to cut some of those in half to get them out. Would have loved to have known what the oil change interval was on that engine! Then as soon as the job was finished, the fuel pump pushrod seized, electric pump to the rescue.
 
#21 ·
Already covered in my post number 14, but nothing wrong with repeating it. It should be sealed because it is not a blind hole, but breaks through into the cam chain area, and hence is exposed to engine oil mist.
 
#20 ·
There are a lot of places where oil could leak on the left side of the engine. Mine used to leak where the stator wires come through the cover. it was not a bad leak, and for a long time I just stuffed a piece of paper towel around it to soak up the oil. I finally cleand the area good with carb cleaner (right before an oil change) and sealed it with silicone. If it is a gasket leak, it would help to know where the actual leak is. Can you take a picture of it, and maybe mark the location of the leak on the picture?
 
#22 ·
If your not sure where it's leaking you can add a uv dye & watch it with a black light. You'll see your oil glowing as it leaks. Makes finding it much easier.
Oh yeah, clean it first.
 
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