RH cover leak

rossness

XS650 Enthusiast
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I had to fish for the tach drive washer on my ‘76 650C so I took the RH cover off. Fished it, out everything back together (save the kickstart), then discovered I tore my old gasket so it started to leak.
Looked like the original so I decided it’s time to replace. Chipped off the old gasket, soaked in paint remover to get all the little bits off, and bought a new gasket from mikesxs.
I watched/read about a thousand threads on putting the Kickstarter back in, which I did successfully. Oiled both sides, put the new gasket on, made sure everything lined up. However, a small bit of the gasket stuck out of the top where the cover meets the case (maybe 1/32”). It looked perfect everywhere else, so I buttoned it up, torqued to spec, and got a bit of a leak. Ran it through a few heat cycles, retorqued, now the leak is worse. It’s definitely coming from the gasket/where the cover meets the case.
Help? Could it be from that extra bit of gasket? I also only have the copper washers on the two bolts next to the oil filter, not the bottom ones (where the leak seems to be coming from). Could that be it? It has never had them on and didn’t leak before.
 
" I also only have the copper washers on the two bolts next to the oil filter, not the bottom ones"

Hey,
Well, yes, you guessed it.
The copper washers need to be on the bolts that are below the level of the oil in the case.
Try replacing them one by one, and hopefully that will do the trick.
 
Yeah guys say there's a hardware store copper washer that fits, 1/4" IIRC you might have to throw 4 or 5 on a bolt and spin grind the OD down a bit. hold them against the grinder wheel with the bolt head slightly down and they'll spin and evenly reduce in size.
 
Whenever I buy from Mikes, I buy a lot. Reason being, shipping is expensive. I'll be captain obvious and say get those green gaskets. The gray/black ones that come with kits suck ass. Yeah right on about the hardware. I have an Ace Hardware and have found several crush washers, fiber washers, o rings, you name it. Hell I just took a 1/4" thumb screw, used a jam nut, and then 1/4" ball knobs to hold my side covers on. Metal side covers.
 
That must be it. It didn't have them on before I opened it up the first time and no leaks, but it looked like it hadn't been removed in 20+ years and was over torqued to hell, I stripped almost all of my bolts trying to get them out and had to buy new ones. Will put those on and see if it buttons up!
 
That must be it. It didn't have them on before I opened it up the first time and no leaks, but it looked like it hadn't been removed in 20+ years and was over torqued to hell, I stripped almost all of my bolts trying to get them out and had to buy new ones. Will put those on and see if it buttons up!
Stripped the bolts?
The case threads will strip before the bolts will.
Or do you mean the allen head of the bolts stripped internally?
If so, are you using the correct (5mm) allen wrench?
 
I'm sorry, stripped the Allen heads. They were on so tight I had to pray them off. I was using a 5mm Allen wrench and socket eventually.
 
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I'm sorry, stripped the Allen heads. They were on so tight I had to pray them off.
Yes, prayer can be effective for many situations..:)

But seriously, if the super-tightness was due to the PO using loctite fluid on them, you might want to clean the threads first, that is, chase them with a tap. Altho this is a delicate procedure, requiring a bit of experience. Which you might have, of course.
CORRECTION: rubbing alcohol can clean out old loctite, if your threads are gummed up with it.
 
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This is my first bike actually. I'm kind of a youngster (25) up against you seasoned vets! I checked the threads before I put the cover back on and they looked ok, didn't see any shavings on any of the bolts when I pulled the either.
 
btw, your issue with stripping the allen head might have had to do with some crud in the allen socket, disallowing the wrench to go all the way in.
 
Also, you shouldn't be making those M6 Allens very tight, just 6 to 7 ft/lbs at most. Actually, it would be better to make them closer to 6 than 7. Sealing a multi-fastener oil holding cover isn't about making all the screws/bolts super tight, it's about making them all the same tightness.
 
Yeah when i replaced the gasket and bolts I torqued them all to 7ft/lbs, which is why I started this thread. I’m guessing the PO just had them so tight it didn’t leak before, but in torquing it to spec it needs those copper washers to seal all the way up.
 
I ran into a motor where a guy re chased the threads to standard. Not sure what I'll do here. Small threaded inserts? Use studs? Pain in the ass. The same motor has an oil leak at the base gasket. Might just part it out. Anywho, I like using a soft wire wheel on a bench grinder. Cleans threads awesome. I use air to blow tapped holes out and very carefully chase threads with the right tap. Keep that tapped lubed up! Ha! I know the shorter shoulder bolts can be bought in stainless at the hardware.
 
I may be misreading this but if you have a leak from the side crankcase cover , did you dress the gasket face before putting it back ?
I always use a piece of wet n dry glued to a sheet of MDF to dress all gasket surfaces . The wetNdry will show up any low or high spots where you may get a potential leak ,which I'll sometimes use a fine draw file to dress down followed by wetNdry but the technique does require some considerable skill if you are to avoid damaging the gasket surfaces. The operation is more of a draw than a filing action.

I reckon using the long hook & loop flat sander is probably the safest and most effective method

 
Yeah, I used paint remover to eat away at the old gasket and a utility knife with duct tape on it to scrap it off. The surface was pretty dang clean and I double checked for any gouges or high spots before I put it on.
 
well if you skimmed it I can't see how it can be leaking really . How exactly did you check the cover and crankcase gasket surfaces for true ?

Did you apply some liquid gasket like threebond to the gasket first before closing up ?

When you close it up again you might apply some Engineers Blue and do a trial fit to see if any low spots show up on both the crankcase and cover gasket surfaces .

I always use threebond as well as a gasket. i know folk say its a pitta to remove but the way I look at it ,if the jobs done right we shouldn't need to open it up again for years .
 
I considered that, but the forum seems split on using adhesive/sealer so I didn’t risk it this time. I’m going to try adding the copper washers mentioned above to see if that seals it. It’s not pouring out, just a slow steady leak.
 
This is a cover I've had to get into quite often, what with clutch work and grinding starter gear repairs. I wouldn't use sealer. I replaced the original gasket when I got the bike but with going in there so often, I wore the replacement out and had to change it again. You can take those copper washers off the oil filter cover screws and move them to some of the lower screws if you like. Yamaha doesn't call for the copper washers there although you often find them. Mine was like that when I got it. Two of the lower washers were missing because they had been moved up to the oil filter cover. I put them back where they belong. My oil filter cover has never leaked without having them there.

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