Base gasket woes

[sthomag]

I've removed my cylinder block for cleaning and reboring, but the the base gasket seems to be welded to it. I've tried razor blades, scraping, paint remover, etc. but it's a long slow process getting it off, and, of course, I don't want to mess up the sealing surface.

Does anyone have any suggestions?

[natemoen]

Just as you said, it is a long slow process....

There are a couple pry locations in the front lower edge that are a very little bit of help, but not much. Biggest problem is that so much crap gets caked on the bolts and fills up the holes and then that sleeve that is over the bolts makes it really hard to lift the cylinders.

[TopCatGr58]

Hey Nate,

I think he said that he already removed the cylinders, but it's the remaining gasket material that he's worried about getting off.

Thom, the base gasket isn't under any real pressure for sealing. Some folks have just put it back together with Threebond stuff and no gasket. With no gasket or very thin layer of sealant vs. the thicker gasket "MAY" provide a little increase in compression by placing the piston a little closer to the head!

So....aside from trying to be delicate in removing the remnants of the gasket....I would get a brass wire wheel brush on a drill and go after it, and then use the 3bond sealant.

T.C.

[kboehringer]

Install the O-Rings

I've removed my cylinder block for cleaning and reboring,

Sthomag,
If you're having it re-bored the machine shop can clean that thing spotless by giving it a quick dip in their bath. They will possibly do that anyway as a precursor to boring. They want clean surfaces too before they start on boring.

Otherwise, there is a permatex gasket remover product available in a spay can that will be very helpful in removing any stubborn gaskets. It doesn't do all the work, but it will soften the thing so scraping it off is very easy.

Personally, I'm an advocate of a gasket vs sealant only. Regardless of your choice of gasketing, the individual cylinder O-rings are not an option. They must be installed.

KURT

[Radioguylogs]

Do you have a gasket scraper?

If you don't have one, a good gasket scraper tool is indispensable.

I am really pleased with the one I bought from Part-N-More.

[XJOK2PLAY]

My 2cents...

Concerning base gaskets...

My personal experience has been this-

There are a couple of choices for those gaskets... the "green" ones that come in a multi-gasket kit, or the individual base gasket from Yamaha.

Multi-gasket kit price= $50
Yamaha Base gasket = $50.

But, take it from me, cheaping out here may cost you big in the near future!
On the back side, at the center of the base, you will see a 2" section that juts out. Those green kit gaskets are thinner material, there seems to be a lack of head bolt sealing pressure in that area, and even though the oil's not under much pressure in that area, the green gaskets WILL blow out not long after you put it together, and you WILL have a huge, messy oil leak there!

The Yamaha gasket is thicker, and does seal much better.

Now, you might use 3bond with the green gasket and have luck, or you may just use 3bond ONLY and get lucky. But, after what I went through after using the green gasket, I'd spend the money and get the Yamaha gasket. In the end, it's cheap insurance.

I'll tell ya this much... oil leaks on a bike SUCKS! Lol...
YMMV, though... just advice from someone who's BTDT. (May only be worth 2 cents??)

Bob

[mack]

Base Gasket

When I did my last one, I used the Yamaha (thicker) base gasket and have no issues. My compression numbers are 168, 169, 171 and 169 cold. I remember it was a real bitch to get the old one off. I put the set of jugs in my ultra sonic cleaner and allowed it to do all the work then took it outside and power washed it with the hottest water I could get out of the tap. That combination got rid of all the gasket, bugs, road tar, oxidization and everything else. Then I took it get the 1179 bore completed and they dipped it again.

[sthomag]

My 2cents...



The Yamaha gasket is thicker, and does seal much better.


Bob

Where does one find a genuine Yamaha base gasket?

[bikerphil]

If you google this P/N, you will find several sources...

2H7-11351-01-00 is the base gasket.

The O-ring P/N is 93210-77363-00

[sthomag]

Well, the I figured out the reason for the base gasket being cemented to the bottom of the cylinder block. Somebody apparently used old-fashioned Permatex, which is shellac-based. The only thing that will shift it is alcohol.

Once I discovered that, getting it off was a lot easier.

Thanks for the tip about the using the stock gasket. I managed to find an NOS one.

[werdna80]

[/I]Regardless of your choice of gasketing, the individual cylinder O-rings are not an option. They must be installed.

KURT

could you tell me the purpose of the cylinder O-rings? I'm a little new at this.

[DiverRay]

They do the real sealing between the jugs and the base. It keeps the oil from leaking between the base and each cylinder. I know, there is a gasket, BUT the o rings keep the oil from creeping up the outside of the cylinder, between the steel sleeve and the aluminum.

[IanDMacDonald]

Just curious- having never done any major overhaul on my engine besides cylinder head work, if I break the engine down past the jugs to replace the base gasket, can I just reassemble it? Or, does the cylinders have to be honed, rings replaced, etc.?

[DiverRay]

It depends on the condition of the engine. At about 50K Kilometers, you should be able to take it apart and re-assemble it without honing. You MUST keep all parts in the same location, but if it's just to replace the gasket and o rings, the pistons would stay on the rods anyway.

[IanDMacDonald]

Thanks Ray. I'm thinking about doing this, and just being done with it.