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Base gasket #^%$##

chuck hahn

chuck hahn

Forum LongTimer
Past Site Supporter
This ones glued on or something. Bikes a 77 gs750. Ive checked, triple checked for any bolts i may have missed, tried getting a putty knife in between cases and the block.....and its not coming loose. Suggestions. Ways to set up something to maybe spread the block from the cases? Any photos of your homemade tools would be great. Thanks.
 
Maybe the pins need some penetrating oil? Can you squirt it down a stud channel?
Ice the cylinders and heat the case?
 
Penetrating oil down the stud holes sound like a good suggestion.
 
I put PB BLASTER heavily down stud holes before closing down last night. I also made some aluminum wedges and will try tapping those in to see if I can get the seal broke
 
Mine was tough too, I tapped front and back lightly with a deadblow hammer and worked it free that way.
 
I'm not gonna be doing any smacking on the fins. Customers bike and a broke fin costs ME....
 
There's a flat spot on the crankcase and a matching one on the cylinder block at each end, find a 6mm bolt or cut one to length and put a nut on it put it on the flat spot and unwind the nut it will break the gasket free and the rest is easy, move it to the other side if necessary, but I've never needed to. I think it's even in the manual or there's a tool that does what i describe. Here:

P1010487.JPG

But a nut and bolt work every bit as well if you put it on the flat of case where the engine bolt hole is and simply unwind it.
 
Last edited:
Ive had some stubborn ones but this ones hands down the winner. Heck i can make that tool easy enough.
 
Got it off. The studs werent very dirty at all but tgere was some brown dope on the gasket. Think it was some Indian Head gasket glue. What a friggin mess cleaning it off too. Tomorrow starts the top end rebuild.
 
chuck hahn said:
Got it off. The studs werent very dirty at all but tgere was some brown dope on the gasket. Think it was some Indian Head gasket glue. What a friggin mess cleaning it off too. Tomorrow starts the top end rebuild.
Click to expand...

LOL. What was it then? Holy Water, a lump hammer or something in between :)
 
Got wedges started in all 4 corners and systematically tapped them in..basically pryed it up till it tore the gasket loose.
 
So it was glued together. That's fine if you only intend to do a head and valve job.
I like you're making aluminum wedges just for this project. Way above the imagination of the average mechanic.
 
Well Bill, the thinness of a 1/8 thick aluminum wedgewill one of two things. Either wrinkle and fold up right from the get go or work itself in. they peeled a little going in but supplied enough opposing force to get the gasket torn. And i mean it literally shredded with chunk stuck on the cases and the jugs. Stuffed rags around all the con rods and a good sharp chisel did the rest.
 
These were scrap aluminum latch bases in the bin at work. What i saw was grind one side and make wedged for loosening the cylinders.....

OjVqo6.jpg


dHpCBn.jpg
 
It's the choice of aluminum that makes it right. Same hardness as the aluminum cylinder case, so not much chance of marring/gouging the surfaces.
 
Wedges bore the brunt of it. Few super tiny dimples at the seam but nothing to worry about as far as the contact surface was concerrned. It s fine.
 
chuck hahn said:
Wedges bore the brunt of it. Few super tiny dimples at the seam but nothing to worry about as far as the contact surface was concerrned. It s fine.
Click to expand...
Sounds good... Won't forget it... I glued a 1260 cyl. block down one time with aviation sealer (glue),We worked a few hrs. getting it off to re-ring it lol. Never again.. But older bikes it's usually the dowel pins or studs..Patience...Combined with good advise like others have noted...
 
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