Technical Q and A for classic motorcycle maintenance and repair.
Editor’s note: If you’re having trouble with that old Suzuki, BSA or BMW, Keith Fellenstein is your guy. From motorcycle tuning tips to detailed motorcycle engine repair, he can draw from a wealth of experience to help guide you to success. Send questions to: Keith’s Garage, Motorcycle Classics, 1503 SW 42nd St., Topeka, KS 66609, or send an e-mail with “Keith’s Garage” as the subject.
Head Gasket Troubles
Q: My 1968 BSA A65 is leaking oil at the head gasket. This leak has been going for quite a while, and before it gets really bad I want to take the head off and try to anneal the copper head gasket and hopefully reuse the gasket. My question is how best to do that with a propane torch? Should I dunk it in water immediately after it gets to dull orange to quench it, or should I lay it on a flat surface to air cool? What other things should I look at with the head off? Would it be a good time to lap the valve surfaces? And finally, what would you recommend for a copper sealant on the head gasket? — Peter A. Akerman/via email
A: You can find people who claim one way or the other is best, but they work equally well. The advantage to the quench method is that it usually shocks the oxidation scale off that you otherwise have to scrub off. I usually use a couple coats of Permatex Spray-A-Gasket before installing a copper head gasket. It’s always a good idea to check the valves when the head is off. If you don’t want to pull them apart to check guide wear and valve wear, you can at least check them for proper sealing. Turn the head over so the combustion chamber is up, then spray penetrating oil into the dome. Go away for a while and when you check back, look for evidence of oil seeping into the intake and exhaust ports. MC