Should I use jointing compound?

[AshimotoK0]

As one who worked on these for many years in the trade, long before you could lay hands on the genuine Honda, or Yamaha, stuff we used RTV all the time and if used as said you dont get any on the filter screen or in the oilways

+1 on that Bryan, I used to use it ,as it was all there was around and a revolutionary product in the 70's. Suppose there are far more ' forgiving' compounds around today though. When I put my latest engines together soon I will be on a new learning curve as what's best to use. I must admit, I too have seen oil holes blocked with orange silicone on PO 's rebuilds but I only ever applied a smear as knew the pitfalls.

Cheers .. AshD

[Drew400]

I can take some comfort from all this advice in that, whilst I have discvovered plenty of old damage inside my poor old engine, there's not a hint of any old sealents, etc.

It seems that I'm about to change all that... but only with the teeny weeniest application, as advised!

D.

[Trigger]

You may laugh boy's but some years ago i had a engine in for a re-build and the casings had been put together with chewing gum. Do not ask me what brand but, the engine had no leaks.

[Clem2112]

Chewing gum has many properties and can as we know survive for many years on pavements etc.

An aircraft maintenance fitter told me he found plenty of redundant rivet holes plugged with the stuff then painted over...
On a USAF  F1-11 bomber !

[bike-pusher]

Chewing gum is also known for being petrol-proof.  Many a vehicle in WW2 had a holed fuel tank plugged with the stuff.  Probably some aircraft as well.

[K2-K6]

Bryan, I wasn't intending to shoot you down on the silicone, suppose I've got a bit of a mortal fear of it having opened up some really grim rebuilds in which they'd just used so much of this stuff that it caused more problems than cured anything.

So sorry for putting you on the spot and  to offer an apology for making it sound like that.

Nigel.

[Bryanj]

No offence taken mate, I have seen a filter screen nearly bunged with excessive Hylomar before now! i think it comes from the old Brit iron where if the goo wasn't at least 1/8 inch thich you still got leaks---still got them then most of the time!

[taysidedragon]

As a long term rider and sufferer of old Brit bikes I had plenty of experience of rebuilding engines!

I usually used Red Hermetite(because that's what my dad had in the shed  ) and never had any problems.

I think most problems back then were caused by ham-fisted owners levering cases apart and damaging the joint faces. Then they used far too much sealant to try and fill the damage. A lot of owners never seem to have heard of tightening down in an even sequence to avoid distortion and WTF is a torque wrench?
No wonder they leaked. 

[K2-K6]

I don't think many people think it through properly in that the better condition and more precise the engineering of the joint then the less sealant it usually requires to prevent it leaking.
I know we repeat it on here, but for some it's not easy to determine just how little sealant you need especially if they are new to this stuff.