2 smoke crankcase sealant

[Shaft]

Might have a chance of picking up a classic 2 smoke single for a sensible price.

It's had a lot of work done and looks the part (only seen pictures so far) but the owner made a schoolboy error and forgot to seal the crankcases when he put it together, hence it leaks gearbox oil into the cylinder.

In my day it was whatever came in a tube, but things have moved on, so does anybody have a clue as to what's the modern day recommendation for sealing compound?

TIA
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20 RE Interceptor, 83 Z1100A3, 83 GS650 Katana
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[Pete.]

I use permatext copper spray gasket, but it takes a good bit of masking. Never failed me though.

In your position I'd two two things:

1. Check each half on a flat plate to make sure there is not even the tiniest burr on the mating edges. Happens a lot where people lever the cases apart.

2. Get some yamabond (or equivalent) and apply it with an artist's brush.
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a.k.a 'Geri'

132.9mph off and walked away. Gear is good, gear is good, gear is very very good

[-]

Yamabond/aka Threebond is the stuff used by a lot of pro 2T engine builders. Put some latex gloves on and smear it around the surfaces.
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Jaguar S Type 3.0 V6 Sport R, VW Transporter T5 GP LWB Shuttle 140ps DSG.

[MarJay]

Yep, Yamabond is what all the pros use these days...
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British beauty: Triumph Street Triple R; Loony stroker: KR1S; Track fun: GSXR750 L1; Commuter Missile: GSX-S1000F
Remember kids, bikes aren't like lego. You can't easily take a part from one bike and then fit it to another.

[A100man]

Are you sure it's not an old crankshaft oil seal? That's the other (usual?) way g-box oil ends up there.
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Now: A100, GT250A, XJ598, FZ750

Then: Fizz, RS200, KL250, XJ550, Laverda Alpina, XJ600, FZS600

[stinkwheel]

[Shaft]

[stevo as b4]

When you strip it, I'd check everything and stuff like the integrity of the crankcase mating faces, that the bearings are all fully seated, and the oil seals are fitted the right way round and not damaged. All that sort of stuff and crankshaft end float etc can all be checked when you strip the engine down to sort the leak. You might have a hairline cracked crankcase or warped mating faces etc.

As for sealant I too used Threebond stuff when re-assembimg my KMX engine. But I think Permatex, Well seal, high temp instant gasket or blue Holomar are all good for sealing joints as long as it's kept out of oil ways (which is were the bad rep comes from).

Whatever you do, don't go onto a certain Yamaha forum as they really are anal about this stuff. Your probably aware that Threebond is just a brand, and they must do at least 6-8types and specs of sealant. I used 1207, but theres loads and they obsess over which ones are for different temperature limits, which are oil resistant and which can be immersed in petrol etc, and how long the shelf life is. Also they'll discuss how and were to apply it, when you should do a leak down test and how long for at what pressure.

Maybe I've no sense, but I've stopped looking at these forums as if you listened, considered and debated everything they all say, you never decide on what to do or get anything done.

As an example, I've always fitted cylinder Base gaskets dry, but listening to that bunch of old women made me smear sealant on both sides of my gaskets, as im not planning on doing a leak down test because I don't have the kit anyway.

[Pete.]

If you're gonna strip it down anyway bring the halves round to mine and I'll blue them up on my big surface plate. I can check the flatness of the mating faces to within 0.005mm
____________________
a.k.a 'Geri'

132.9mph off and walked away. Gear is good, gear is good, gear is very very good

[Shaft]

Ta for all your help folks.

Stevo, that's exactly what I was thinking when I started this. In my day, there was blue or red Hylomar, red was for permanently gluing stuff together, blue was for everything else.

Just looking at the range of stuff we have at work, there seems to be a gunk for every occasion!

Pete, thanks for the kind offer, but I'm hoping not to get to a totally bare case situation.

To be completely honest, I have no interest in this bike, other than to make money - the information was passed to me and, having weighed everything up, it seems almost too good to be true.

Assuming it gets into my hands, the plan is to strip the motor to the minimum I need to seal the cases (I want to leave the gearbox internals in place and everything) check it as far as I can with a straight edge and MK1 eyeball, then chuck it back together and flip it.
____________________
Things get better with age; I'm close to being magnificent........
20 RE Interceptor, 83 Z1100A3, 83 GS650 Katana
WooHoo, I'm a Man Point Millionaire! https://www.bikechatforums.com/viewtopic.php?t=234035

[A100man]

Hi Sorry I just re-read the OP. So he admitted to not sealing the cases?
Does make you suspect other work that's been done in that case.

Plus.. IIRC the red stuff was Hermatite and considered a poor relation to blue Hylomar in the 70s 80s as teenagers. No idea why though.
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Now: A100, GT250A, XJ598, FZ750

Then: Fizz, RS200, KL250, XJ550, Laverda Alpina, XJ600, FZS600

[Shaft]

[MCN]

Loctite make a the bestest sealants.
They cure in the absess of oxygen.
Two gasket makers are one sets like a hard glassy plastic, the other sets like a more pliable plastic.
They stick lime shite to a blanket and if the surface is prepared correctly the seal is permanent.
Permeated is a silicon product. I don't think it's as good in pressure jobs.

https://www.henkel-adhesives.com/uk/en/products/industrial-sealants/liquid-gasket-solutions.html
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Disclaimer: The comments above may be predicted text and not necessarily the opinion of MCN.

[Shaft]

[A100man]

Link to and/or photos of the offending article now required..
____________________
Now: A100, GT250A, XJ598, FZ750

Then: Fizz, RS200, KL250, XJ550, Laverda Alpina, XJ600, FZS600

[Shaft]

Sorry, no links, it wasn't widely advertised, I got wind through word of mouth.

The only pictures I have are what the owner sent me, which won't tell you much and I'm not going to post them anyway, after the way I've described him here, I'm not going run the risk of embarrassing him or me by allowing him the opportunity of finding them on the net.
____________________
Things get better with age; I'm close to being magnificent........
20 RE Interceptor, 83 Z1100A3, 83 GS650 Katana
WooHoo, I'm a Man Point Millionaire! https://www.bikechatforums.com/viewtopic.php?t=234035