Forum

[devon john]

rebuilt the engine 535cc ,i had a oil weeping near the pushrods, so i changed the head gasket for a solid copper one, if anything it worse !!
i used well seal and torqued it done
should i have gone for the composite gasket???

[Gwilly]

John its possible you may have to lap the barrel spigot to the head recess using valve grinding paste..

With the gasket removed finger tight the bolts and measure the gap between head and cylinder deck..

Measure the thickness of your gasket which should be say 50% thicker than the gap it has to fill...

If its about the same then it will not be compressed sufficient to prevent blowout leakage...

Lap the head, turning cleaning and measuring until gap is correct..

Check gasket holes line up nicely with push rod tunnel and ensure copper gasket is annealed before use.

Heat to cherry red and quench in cold water..

Or use composite gasket dry...

[apparently lucky eddie]

I'd say stick to the copper gasket but be sure it is annealed (you can do it on the gas cooker)and use a smear of red hermetite - you can still buy the real stuff on fleabay. Beware of silicone sealers inside the engine, it can block oilways, and there are no end of horror stories regarding composite gaskets disintigrating online.
Regarding persistant oil leaks, I've been cussing the pushrod oil seals on my old Triumph for leaking. Turned out to be not the pushrod seals but the nuts holding the barrels to the crankcase had come loose, something I have never seen before. My 19 year old daughter, who has had zero mechanical tuition, has carefully stripped down the engine and is now putting it all back together with new gaskets and virtually no input from me. In exchange for the resulting destruction of her fingernails I have had to promise to take her down to the beach when the bike is running and teach her to ride it!

[Adrian1]

You need to retorque several times after a few miles as the gasket beds in. If its still leaking,run a small bead of high temp silicone around the head where it meets the barrel. Works like a charm.

[wilf]

Hi Adrian,my bullet has a bit of a weep from the head gasket, just under the de-compressor. Are you saying that high temp silicone may do the trick without taking the head off?

[Alan R]

------- OR, you might just have an inclusion ( a small bloew-hole ) in the casting that's only just now decided to show itself ?? ------------- I've had TWO of the blighters in the past !!

[wilf]

That sounds serious, is silicone worth a try? What's fix for faulty casting?

[Alan R]

Hi WILF-------- actually it's not as bad as it sounds ( Depending on just where the porosity happens to be )..............The two I had were}---1) Halfway down the exhaust pushrod tunnel in an Aluminium barell ( a known "cheapie" from E-bay)....Repair was to open the tunnel out and line it with some standard Aluminium tube.......................... 2) A persistent weep on a Bullet 65 in the cyl. head / exhaust valve / barell joint area...Repair was to drill-out as much of the cavity that was accessible, peen over the area, wash with a strong de-greaser ( Acetone) and quickly cram full with a 2-pack metal paste............................The porosity is the result of poor}-- casting processes / Aluminium material where pockets of gas are trapped within the liquid of the item being cast..... You pays your Rupees... etc, etc..