Is there a specific silicon sealant that is recommended for the crank cases? If so, could somebody point me in the direction of a supplier?

Thanks!

You need triplebond 1104 over in aus most dirtbike shops have it in stock.

Fantastic. Thanks!

1104 is good at sealing and resistant to most things, but the nastiest thing to use. Usually end up with it all over the place.

1207B is much nicer, and HRC use it. On the downside it's a lot lot lot more expensive. If you only intend to use it every now and again then go for the cheap option.

Whatever you use, make sure the case is spotlessly clean and free from any oil/grease or it won't seal.

i use Threebond 1207B and have enjoyed great results
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After years of moaning about immigrants now i am one...

1207B is really nice stuff.

NSR-World statistics show that 1207B is the weapon of choice.

Not sure about the real world, but over here 1207B is not available commercially. Have to go to the Threebond factory to get it and costs over 20 quid a tube. 1104 on the other hand is in every hardware shop and costs about a quid for a small tube.

If Paul goes near my 1207B he will get his hand slapped.

For all those in Sydney, or all of Australia pretty much.

I had trouble finding it at all the usual suspects.

Found these guys on the net - http://www.highperformanceworld.com.au/store/three_bond/

I was skeptical but dropped in as it's close to my work. Asked the guy behind the counter. He didn't blink - "100ml or 300ml?" he says.

Even got a small discount off the listed price. Recommended.

i just read to apply Threebond 1207B to one side of the engine case only. I was taught to apply it to both sides. Which is correct?
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MC21R9N track
MC18R2J track
CBR954
CR250

Only one side mate...

I apply to both sides with a faint layer.

Two reasons I do this. First because Harc-Pro insisted (HRC instructions), and secondly because it's a good way of knowing that both surfaces are spotlessly clean and free from grease/oil etc that may stop the cases from sealing properly.

1207B cures slowly so I'll do the bottom case first, then grease the dowels and pop them in, followed by the crank. Then apply sealant to the top half and drop that on. Press it down by hand to make sure the crank seals and what have you are all lined up properly. Then gently pull the cases together with the M8 bolts, starting with the middle two. Tightening in a couple of steps up to final torque. At each stage of tightening I give the bolt heads a crack with the mallet which helps centre the crank so that the main bearings are under no axial stress.