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03-17-2009, 1:58 PM kingston73 Joined on 04-19-2008 Bellingham, MA Posts 1,722 I think I know the answer - Oil Leak question So like I said, I'm afraid I know the answer but I'll ask anyhow.  If I have an oil leak from the bottom center of the rear cover, is the only way to fix it to drop the engine and replace the gasket?  I thought it was fine, it sat overnight with zero drips, but after I got back from an hour ride today it was dripping pretty substantially.  I used an aftermarket gasket, which in retrospect I should have just used as a template and cut out my own from 1mm gasket paper.  I need to replace the clutch cover gasket too, also from the same source.  If it is as I fear and an engine out job, are there any shortcuts I can take to make the job any easier?  I'm assuming I can leave the radiator and shroud on the front, and I'll leave the carbs attached to the airbox.  Man, I want to kick myself for using a cheap gasket! 1979 cx500D - mostly stock    Report

03-17-2009, 2:04 PM Vee Dub Nut Joined on 01-03-2009 Texas, USA Posts 232 Re: I think I know the answer - Oil Leak question I think you and I used the same gasket kit and I have had ZERO leaks from my engine since I got it back together. Make sure that you have all of the old gasket scraped off before putting the new one on. Any little debris left behind can cause major annoyances with leaks.. The clutch cover gasket is easy to replace in frame, but the rear cover replacement means that the engine has to come back out. That's really not too big of a deal as it only takes half and hour to have it out on the floor after you do it a time or two. You can leave the radiator shroud and the carbs on the engine while you drop it out. The carbs will have to be pulled off to get the rear cover off though once its all out on the floor Adam Brandt Fightin' Texas Aggie Class of '06 00 VW GTi 67 VW Beetle 79 Honda CX500D - SOLD as a sacrifice to the VW gods, aka new VW project LOL    Report

03-17-2009, 2:25 PM kingston73 Joined on 04-19-2008 Bellingham, MA Posts 1,722 Re: I think I know the answer - Oil Leak question Yeah, that's what my thought was too, I must have missed cleaning off a piece of old gasket.  I didn't use much permetex when I put the new gasket on, did you use any when you put your's together?  I was just looking at the gasket paper I have, and it's just a very little bit too small for the rear cover gasket to be made in 1 piece.  I remember reading a post about somebody who made a 2 piece gasket but can't find it.  How would I do that?  This will be the 2nd time in a week that I will have dropped the engine, so hopefully you're right and it'll go quicker this time around.  It's weird that it didn't leak when cold, only after things got warmed up.  I would have thought it'd be the other way, any thoughts on why that happened? 1979 cx500D - mostly stock    Report

03-17-2009, 3:16 PM Vee Dub Nut Joined on 01-03-2009 Texas, USA Posts 232 Re: I think I know the answer - Oil Leak question Dunno what caused the leak... no telling really I didn't use any gasket sealer (permetex, silicon, etc).. I've gotten where I won't put anything on gaskets when I have a nice clean surface and a good quality gasket. I've had more troubles with leaks when using extra sealants than without. Adam Brandt Fightin' Texas Aggie Class of '06 00 VW GTi 67 VW Beetle 79 Honda CX500D - SOLD as a sacrifice to the VW gods, aka new VW project LOL    Report

03-17-2009, 3:39 PM Blindstitch2002 Joined on 05-16-2007 Greenfield Wisconsin Posts 5,000 Re: I think I know the answer - Oil Leak question Any chance this could fix itself by running it for a while. I mean not 10 minutes but how bout giving it a week? If you didn't have an H box I would suggest to wipe the joining area and clean it up and smear a hair of rtv silicone in the grove. Or trying to tighten up the bottom bolts a bit. Because weren't the fronts slightly leaking? Oh where are you guys getting these gaskets that are leaking? 1978 Honda Cx500 Maggot 1979 Honda Cx500 Custom 1980 Cx500 Deluxe Buy HTTA Items Quick Reference Info    Report

03-17-2009, 3:47 PM kingston73 Joined on 04-19-2008 Bellingham, MA Posts 1,722 Re: I think I know the answer - Oil Leak question I found mine on ebay, part of a full gasket/O ring set.  I don't think running it will work, if anything it made the leak worse.  That's weird because generally heat seems like it would make parts expand and seal better, not worse.  Yeah, I had a leak in the front too and that's gone now, but this drip in the back got really bad today, so it's back to dropping engines and taking rear covers off again.  Hopefully this time will work! 1979 cx500D - mostly stock    Report

03-17-2009, 3:54 PM Blindstitch2002 Joined on 05-16-2007 Greenfield Wisconsin Posts 5,000 Re: I think I know the answer - Oil Leak question Guess that's a good reason to buy the honda gasket or correct size gasket paper and make you own. Funny how a few extra bucks can save a lot of hassle. 1978 Honda Cx500 Maggot 1979 Honda Cx500 Custom 1980 Cx500 Deluxe Buy HTTA Items Quick Reference Info    Report

03-17-2009, 4:50 PM Blue fox Joined on 04-18-2008 COLUMBIA, MISSOURI Posts 1,533 Re: I think I know the answer - Oil Leak question I just got my OEM Honda gaskets today and decided to buy some paper and trace a couple out from the original Honda gasket for the next time.  I started at Car Quest and the paper they had was about 60mm thick.  (I took my mic along).  To get the width you will need to go to the 18"  wide stuff.  I picked up a box from Car Quest and brought it home.  They wanted $13 for a 18x36" roll.  I knew the original thickness by my mic was closer to .54 mm, so on the the way home I stopped at OReily Auto to see if they had some thinner stuff. They had some .58mm Feld-Pro material so I picked up a 18x36 piece of that for $6.00.  I think I'll be alright with the .58mm stuff, that isn't much difference.  I plan on tracing as many rear cover gaskets as I can get from this piece before I install the Honda gaskets on the bike.  I think I can maybe get 3 rear covers and inside those I plan on tracing the tach and advancer cover gaskets.  I didn't pull my front cover, so I don't have one of those to trace.  Blue Fox 1983 GL650I, 79-CX500C, 1980 CX500C, 82-GL500I, 82-GL1100, 76-CB550, 81-CB750C, 73-CB350F, 71-CT90,    Report

03-17-2009, 5:05 PM kingston73 Joined on 04-19-2008 Bellingham, MA Posts 1,722 Re: I think I know the answer - Oil Leak question Do you know what the OEM thickness is? I'm going to make a trip over to Autozone and see if I can find some wide enough tomorrow. I'm guessing thicker is better than too thin? 1979 cx500D - mostly stock    Report

03-17-2009, 6:13 PM Blindstitch2002 Joined on 05-16-2007 Greenfield Wisconsin Posts 5,000 Re: I think I know the answer - Oil Leak question Thin will bind on the rear case as I have never heard any problems related to to thick. 1978 Honda Cx500 Maggot 1979 Honda Cx500 Custom 1980 Cx500 Deluxe Buy HTTA Items Quick Reference Info    Report

03-17-2009, 6:27 PM Blue fox Joined on 04-18-2008 COLUMBIA, MISSOURI Posts 1,533 Re: I think I know the answer - Oil Leak question I miced the original rear gasket, and my mic shows .02141 inches, or .54mm.  Sorry about the above numbers, in the previous post,  must have been drinking again, Don. Blue Fox 1983 GL650I, 79-CX500C, 1980 CX500C, 82-GL500I, 82-GL1100, 76-CB550, 81-CB750C, 73-CB350F, 71-CT90,    Report

03-17-2009, 6:35 PM Blindstitch2002 Joined on 05-16-2007 Greenfield Wisconsin Posts 5,000 Re: I think I know the answer - Oil Leak question I was a bit curious how you were going to make the gasket out of 25mm or 1 inch gasket paper but to each his own. Going to add this to my quick list. 1978 Honda Cx500 Maggot 1979 Honda Cx500 Custom 1980 Cx500 Deluxe Buy HTTA Items Quick Reference Info    Report

03-18-2009, 4:13 AM roadster5580 Joined on 01-18-2008 Atlanta, GA Posts 326 Re: I think I know the answer - Oil Leak question Making gaskets is some times very simple and at others not so easy as it would appear.  Most people think "gasket material, is gasket material", not so.  There is a huge stock of different material available.  Google gasket material and you'll see what I mean.  Ever notice how some "factory" gaskets appear kind of slick and waxy looking?  Flexible graphite or graphite impregnated. Other gasket material you see at Auto Zone or PEP Boys looks like just regular old paper... and it is. One of the biggest problems engineers face in designing an engine is how to "seal it up" to keep it from leaking.  If you've turned wrenches on cars over the last 15 years, look at the problems GM has had with intake gasket failures.  So if GM can't figure out how to get an intake gasket to seal for 15 years, what makes you think that you'll have any better luck running down to the local auto store and buying whatever "on the shelf material" they have (usually the cheapest) and think that it's not going to leak after you've spent a week rebuilding and installing the engine?  The old British bikes (Norton, Villiers, BSA, Triumphs) with a vertical splitting crankcase were notorious for oil leaks between the cases.  I know there is going to be someone on this forum that says ... "I've always made my on gaskets and never had a problem".  IMHO (after 40+ years as a mechanic) making your own gaskets is a 50-50 proposition at best and you have to have the right tools, material, and sealant to pull it off.  As a professional, I can under no circumstance chance a "come back".  Imagine how pissed you as a customer would be if you had just paid me big money to fix your bike and it developed a leak like Kingston73.  Not worth my time or reputation to make gaskets, but if you must, here's what I know about sealing crankcase covers: 1)  Don't buy cheap gasket material.  Use Flexible graphite or graphite impregnated.  Buy Fel-Pro or Duron not Chinese made crap.  Buy it at the local speed shop -  where the drag racers go.  They can't pass tech inspection if their engines leak 2)  Clean the hell out of the surface.  Use Scotch-bite pads on a die grinder and wipe it down with Lacquer thinner before applying sealer 3)  Don't use cheap sealer (forget RTV sealant, Prematex, and silicone).  Use Loctite 504 or Yamabond.  Expensive tube, but a little goes a LOOOOONG way. 4)  Don't "Goober" on the sealer.  Your sealing a joint not icing a cake!!!!  With 504 or Yamabond, pencil lead thick is plenty. 5)  "Rolled" gasket material tends to want to stay rolled.  Iron it.  Apply a little heat with an old iron in order to get it to lay flat and make it easier to work. 6)  Use a VERY sharp exacto knife.  Make your cuts very sharp and crisp.  Don't use scissors, really good gasket material is laminated and you seperate the material by chewing through it with scissors. 7)  Use "gasket cutter punches" to get a crisp cut for the bolt holes.  Don't drill 'em or ream 'em with a screwdriver....   LAMINATED!! 8)  Make sure the case cover is not warped.  This was the problem with the old British bikes and can only be corrected with a "lap plate".  Poor mans lap plate  -- Piece of glass with #200 grit sandpaper glued to it.  Take a wide felt-tipped pin and coat the gasket surface of the cover all the way around.  Flip it over on the lap plate and gently start a circular motion.  Continue to "lap" the case until the all of the felt-tipped marker disappears.  The case is now square. 9)  Always apply the sealer to the metal and not the gasket.  It's a two-sided seal process. "Glue" the gasket to the "block" first.  Put a couple of cut-off longer screws through the bolt holes to help align everything and keep the gasket in place.  Use a round screw driver shaft to press and smooth the gasket to the block and establish the seal all the way around the perimeter. Allow the sealer to "set" (about 5-7 minutes with 504 or Yamabond).  This establishes the first seal and sets the gasket so it doesn't move when installing the case.  For the second seal, apply the sealer to the case surface.  Start the case into place using the cut-off  screws as guides, even if there are alignment pins. 10)  Get a couple of fasteners installed and remove the "guide screws".  Finish installing all the fasteners and start torquing everything down right away.  Follow any torque pattern in the service manual, if there is no pattern,  start in the middle and work your way outward in a crossing pattern from bottom (oil side) to top.  Use a "three pass" torque process -- 40% -- 40% -- 20% final.  All this needs to take place in the 5-7 minutes it takes the sealer to set. 11)  Wipe the outside down with lacquer thinner on a rag and pray it don't leak after you spent all this time and care That's how I was taught.  As you can see it's a lengthy process.  Lots of opportunity to screw up.  Like I said at the start, I always try to use factory gaskets.  The guy that taught me used to always say -- "After you do all this crap and it still leaks, you can always blame it on Honda and the reason the Japs lost the war".    Report

03-18-2009, 4:25 AM Len in PA Joined on 03-31-2006 Bristol, PA Posts 485 Re: I think I know the answer - Oil Leak question Roadster, An excellent tutorial that make me want to stick with Honda gaskets, as you mentioned! '82 GL500i...nearing 100,000 miles    Report

03-18-2009, 4:27 AM ezzee Joined on 08-20-2008 CT Posts 857 Re: I think I know the answer - Oil Leak question Good info Roadster, thanks, one question, does the loctite 504 and Yamabond release if or when  you have to take the covers off again ? 1978 CX 500 1981 GL 500 1981 Custom 1982 GL    Report

03-18-2009, 4:39 AM roadster5580 Joined on 01-18-2008 Atlanta, GA Posts 326 Re: I think I know the answer - Oil Leak question Yep -- 504 is an anaerobic sealer.   Don't need a jack hammer like Black Permatex... They ought to outlaw that crap As far as come backs for oil leaks on British bikes... Same old guy that taught me used to say ... "We need to start moving this shop every couple of months, that way these guys can't find us".    Report

03-18-2009, 6:28 AM Blue fox Joined on 04-18-2008 COLUMBIA, MISSOURI Posts 1,533 Re: I think I know the answer - Oil Leak question I had a Triumph in the 70's that was very easy to check the oil on........... When it stopped dripping, you were out of oil.   Blue Fox 1983 GL650I, 79-CX500C, 1980 CX500C, 82-GL500I, 82-GL1100, 76-CB550, 81-CB750C, 73-CB350F, 71-CT90,    Report

03-18-2009, 6:33 AM kingston73 Joined on 04-19-2008 Bellingham, MA Posts 1,722 Re: I think I know the answer - Oil Leak question See, ya learn something new every day.  I didn't know permetex wasn't great.  So the Loctite 504 is generally considered better than anything else?  I believe everything you said Roadster, I'm still going to give it a try at making my own because otherwise I'll be waiting at least a week or 2 for a new OEM gasket. I know Triumphs were infamous for oil leaks, but never knew why.  Was it just poor tolerances?  Basic design of the block?  What was it about them? 1979 cx500D - mostly stock    Report

03-18-2009, 7:06 AM roadster5580 Joined on 01-18-2008 Atlanta, GA Posts 326 Re: I think I know the answer - Oil Leak question Poor mating on the case halves.  Vertical splitting case.  Vibration loosening the case screws.....  In the 60's, Honda was considered inferior to British bikes until people noticed right away they didn't leak oil nearly as much.  Horizontally split case Get the good gasket material, Loctite 504, and take your time.  Spend an extra 20-30 minutes here and you can save spending a couple of hours later pulling/re-installing the engine later. Did you change a Mech Seal while you had it apart?  If you did, and heated the case in an oven, I would go through the process with with the magic marker to see if the case is "square".  Use a couple of sheets of #220 grit sandpaper.  Take "double-sided" tape and attach them to a large enough mirror or even a window.  Work it gently in a circular motion until all the marker ink disappears.  It's easier to work on a horizontal plane, but a window will work in a pinch.  The trick is to be gentle. Good Luck    Report

03-18-2009, 7:26 AM kingston73 Joined on 04-19-2008 Bellingham, MA Posts 1,722 Re: I think I know the answer - Oil Leak question Well, after reading your post and the fact that I did fix up the insides and don't think (hopefully) I'll have to open up the rear of the case again for a long time, I decided to call around and see if there where any OEM gaskets to be had. Found a place that is going to get me one by friday or saturday nearby, so I'm just going to spend the money and get it. I'll use 504 and check the rear cover for square. Thanks for the help, hopefully I'll be leak free by the end of saturday so I have all day sunday to ride. Weird though, still can't figure out why engine heat caused it to leak.  It dripped a little and then stopped when I first put oil in, so I thought I was good.  Oh well, live and learn. 1979 cx500D - mostly stock    Report

03-18-2009, 9:28 AM roadster5580 Joined on 01-18-2008 Atlanta, GA Posts 326 Re: I think I know the answer - Oil Leak question Not only did the case expand when it heated up it, contracted when it cooled back down.  The gasket,case cover, and sealant "seated".  I'll bet when you take the engine loose this time, that you can get another 1/4 turn out of each case fastener from what you set the torque at the first time. Experienced mechanics (especially on high-compression diesel engines) will even "re-torque" head bolts after a rebuild for just this reason. I know what you're thinking ..... Maybe all I have to do is? ..... Maybe, maybe not.  1)  The engine has to come out either way 2)  You don't know if the case is "square" 3)  504 Loctite holds up better to heat than Permatex (and expansion/contraction) 4)  The OEM gasket is on the way 5)  I hate maybe's when it might involve pulling the engine for the third time Good Luck    Report

03-19-2009, 12:09 AM Lambykin Joined on 09-14-2008 Burlington, Ontario Posts 1,076 Re: I think I know the answer - Oil Leak question I'm not a professional mechanic, but after working on cars for the better part of my life, I can agree with Roadster. Can't stress enough about how clean the gasket surfaces need to be. Just because it LOOKS clean & shiny doesn't mean it is. Use a proper cleaner & a clean white lint-free cloth/rag on the gasket surface after properly removing the gasket, and you'll see how much dirt & grime there is left. Patience in this area is quite important. The moment you get the urge to just finish the job and cut corners, you'll end up with a leak. I'm sure you'd rather spend the good weather out riding, than chasing after leaky components. Evidently, I've got my engine out for the very same reason - leaky rear cover gasket (believed to be original). Only want the engine out once - after I'm done, I don't want to have to do it over again. Another important point - don't over torque the bolts. You could over-crush the gasket, rendering it useless. I'm pretty certain this is what Roadmaster was driving at when he explained torque sequence, and "stepping" the torque. You don't want to warp the components by placing too much stress in one area, and you don't want to crush the gasket to the point that it is unusable. 1982 GL500 Interstate 1981 CX500 Custom 1985 Pontiac Fiero (2 of 'em) 2005 Honda Accord EX-L V6 Coupe    Report

03-19-2009, 2:15 AM Len in PA Joined on 03-31-2006 Bristol, PA Posts 485 Re: I think I know the answer - Oil Leak question Re: Triumph oil leaks. In '67, when I had a new Bonneville, I kept it in a friend's garage. He fabricated a sheet metal pan that went between the tires to catch the constant leaks from three locations! '82 GL500i...nearing 100,000 miles    Report

03-19-2009, 2:57 AM roadster5580 Joined on 01-18-2008 Atlanta, GA Posts 326 Re: I think I know the answer - Oil Leak question They amazing part about how much the old British bikes leaked oil was that they were supposed to be a "dry sump" engine like Harley.  Transmission and engine were not integral.  They had an oil tank on the right side under the seat.  When the engine shut down, most of the oil was in the oil tank and slowly drained back into what was supposed to be the "dry sump".  Even the earliest CB750's had an oil tank on the right side, but the Honda was a "horizontal split" on the case. Can't recall, but it seems like Triumph didn't come out with an integral "wet-sump" design until about the mid-60's on the Bonneville and it still leaked like hell.  I knew a lot of old time bikers that rode British and Harley.  They routinely ran straight 50w oil and added STP to slow the leaks down.  I even knew some guys that went as far as putting "shut-off" valves in the oil lines.  When you got ready to shut down, you turned the valve closed on the inlet line.  Ran the bike for another 20 seconds and the closed the valve on the return line.  It captured the oil in the tank for overnight parking.  Don't wake up with a herb hangover and forget to turn the oil lines back on!!!!! Can you imagine putting a modern 20w50 oil in one of those bikes?  You'd have to mount the "drip pan" under the frame and rig up a return hose to keep oil in it on a 100 mile ride.     Report

03-19-2009, 3:10 AM Len in PA Joined on 03-31-2006 Bristol, PA Posts 485 Re: I think I know the answer - Oil Leak question Amen to that! '82 GL500i...nearing 100,000 miles    Report

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