OzVMX Forum
Clubroom => Tech Talk => Topic started by: PEZBerq on May 24, 2008, 09:00:15 pm
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What's the deal with the liquid gasket sealants available these days ???. Can you use it on crankcase halves if you dont have a paper gasket available? What about reed valve assemblys. I have some Threebond Grey - is it any good? Cheers Steve
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depends on what its being used for mate
Lots of parts need gaskets of specific thickness for clearance and liquid gaskets cant do that .Other applications ive found it to be fine .
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I use Threebond 1215 grey on everything from Cat engines to yamaha .It;s the best .
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OK the grey sounds good ...but would you use it on a crankcase joint? cheers
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Threebond grey is really good stuff ;), It can stop old pommie bikes pissing oil out ,yep slows it down to a fast dribble. Porous cases what a nightmare!! >:( Cheers Tim Ok use the gasket too!!!!!!!!!!!!!!!!!!!
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not on a crankcase for an older bike mate as that is the gearbox aswell and you may find your end float for the gear shafts would be out of spec and start causing you probs.in conjusction WITH a gasket yeah great stuff
Moderns seem to be engineered to use the new gasket in a tube
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Thanks gents. A gasket it is with a dash of threebond!
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KDX 200's have no centre gasket and rely on 3Bond.Used silcone on many and varied places trick is to wait a bit and let it go tacky before the bolts go in.
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yep the grey threebond is a bit expensive but is the best. i believe the Blue Aero/hylomar stuff is the best for head gaskets. Loctite 515 is another one i use often for certain things like reed blocks
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mmm..just shows different schools of thought. I never use any sealant on any engine case or covers of any bike motor unless it came sealed from the factory that way in the first place. A nice new gasket, clean dry surfaces, a smear of clean oil to get the swelling happening, tighten it up evenly and Bob's ya Uncle ;) in an emergency I may use 3 Bond but very sparingly and I actually don't remember the last time..the tube I have is still marked with a $42 price sticker, I bought it back in about 1980 so God knows how much the stuff is worth nowday ;)
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$32
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yep $32 is about what i sell it for too. good to know not everything has gone up in price.
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Yerp I use Hylomar myself . easy to use easy to clean and it works. specially if you have crap casings. I use to advocate just the gasket with a smear of grease but i find the hylomar holds the casing a bit better and the screws dont come loose from vibration.
or maybe i just like the smell and the pretty blue colour ;D
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hmmm $32 eh Loz.. :-\ shit..when I got mine I couldn't buy it anywhere and ordered it through Kawasaki using a part number..perhaps 'this is' why I paid such a ridiculous price way back when..least I still have the bulk of it so if I break the cost down over the period of usage it'll be easier to live with my mistake fer sure! ..ummm just a sec..I'll just punch some buttons here..ok!..:P 0.004 cents a day my mistake has cost me..ummm..errr..for the last 27 years..lets see..that's about 9800 and something days..oh bugger! :P screwed again no matter how I look at it! ::)
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Loctite master gasket 515 does it for me
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Yamaha YZ's dont use a centre gasket for the cases, they just need sealant (yamabond).
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Help!!! Just pulled my cases apart for the third time...... >:( >:( >:( >:( Failed a 3 psi pressure test using the grey Threebond and the paper gasket the first time. Leaking out the casing main half joint.
How long should you wait until doing the air test? I put about 20kPA in - 3psi after buttoning up the cases with the Threebond and it pissed out. Should I have waited for 24hrs or so for the Threebond to cure properly?
I used a really thin smear of Threebond on the casing halves. It seemed to have gone dry before I finished and stuck the halves together. Is this OK or should I have used a thicker smear that takes longer to dry?
Anyway then decided to try paper and smear of grease for the second attempt (seemd a good idea at the time). Still no good - leaking air same as before. ::) ::)
Pulled apart for the third time and now wondering what to try next. ??? ??? Half joint surfaces appear reasonable - not perfect but were sealing Ok before the tear down to fix sticking gearbox. Torqued up screws to factory 6 ftlbs and checked them so half joint should have correct clamping force on it.
Any suggestions? Pokey mentioned Hylomar..is that a sealant of last resort?
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Try a straight edge( steel ruler ) on your case surfaces and check for warping ......then use loctite 515 ;)
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Hylomar is what rolls royce use to build thier engines if ya can believe the can.
I like it as its not messy and works well and is easy clean up when doing repairs
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This might sound pretty rough, but back in the early 80's while working at a Yamaha dealership, the mechanic would use contact cement (the yellow glue that you allow too dry on both items before putting them together) to seal up any centre case joint that leaked when 3-bond wouldn't seal the joint. It worked every time, and I will admit that I have used this method on some of my older engine, i.e. my 1949 Matchless G80, and it doesn't leak from the centre case joint. It leaks from most of the other though!
I use Loctite 515 on all of my 500 Yamaha engine and have not had any problems with leaks.
CJ
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and to answer the question I normally leave my gasket/goo setup for 24 hours before filling with oil etc - learnt it the hard way - it appears most of the new goos require the setting time.
cheers
Rossco
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Loctite 515
I've rebuilt shitloads of Ducati's among other things in the past using the stuff and I can't fault it
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Left the sealant to cure for 24 hours and the air test was successful finally. What a goose......expecting liquid sealant to seal while it was still liquid :-[ :-[ Now to see if the jetting problem has been fixed......... Thanks for the help.