BS? Backing off to re torque is common practice.
Can you please explain your point above point? I just don’t understand.
Its important to address a few misconceptions often circulated online or by those without hands-on experience. Many who suggest practices like head bolt retorque are either following outdated advice or simply echoing what they've heard from others on forums without understanding the engineering behind it.
First off, let's consider modern vehicles—whether cars or motorcycles. When was the last time you had to take a new vehicle back to the dealer for a head retorque after an initial service? Probably never. That's because once the initial torque sequence is complete, there's no way to replicate it without compromising the integrity of the gasket. If you loosen those bolts for a retorque, the gasket won't return to its original state, which is why bolt marking is done. This lets you visually confirm if anything has shifted.
Moreover, every major modern gasket manufacturer will tell you that a retorque is unnecessary. These companies design their gaskets to perform optimally with the initial torque and bolt stretch. Even in a Harley, which is a close comparison to the 961, there’s no factory procedure for loosening and re-torquing head bolts.
Now, in the case of the 961, it's true that the engine components aren't up to the same quality standards as more refined engines. Norton included a TSB head bolt check because the bolts, gaskets, and other components are of lower quality, the motor tends to run extremely hot, and they had issues with build quality. It's essentially a way for the manufacturer and dealers to cover themselves for potential issues arising from subpar parts
Take ARP, for example They will never advise you to back off a bolt that’s already been torqued to spec. Instead, they recommend the use of their Ultra Torque Lube to ensure consistent torque readings and to prevent issues like galling. The emphasis is on consistency, not revisiting bolts that have already been stretched and torqued.
If you're insistent on checking torque, that's fine. But if you decide to start backing off fasteners that have been torqued at the factory, especially when the factory manual advises against it, you're asking for trouble. A quick check with a properly calibrated torque wrench, followed by paint-marking the bolts, is sufficient to monitor for any movement. If you're finding that a bolt has shifted an 1/32 or more, you've likely got bigger problems to address than just the torque. Something else in the system could be failing, misaligned or wasn't done correctly to start with from the factory.
Now if you want to talk pre 1980 engines that's another discussion.
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