I'm sorry, but could you remind me how many 961s you own? Also, have you torn down any 961 engines to the cases, headwork, or valves? Have you had customers ship them to you from all over the USA for repairs/service? I just want to get an idea of whether you have any practical hands-on experience with these bikes.
When someone is critical of the relevance of the other person's contribution and the overall tone comes across as dismissive or impatient with the current direction of the conversation that's about the time I quit contributing to these forums.
So, if I install a new gasket that is better than OEM quality, would I need to follow the retorque procedure again after that, or is a modern gasket that the manufacturer states requires no retorque ok with you?
My point about modern vehicles is indeed really relevant, as this is more of a late 90s/early 2000s engine that has modern gaskets in it. While not quite as nice as the gaskets Ollie has, they are still serviceable products when installed correctly.
And regarding re-torquing, Ah, my mistake! You're absolutely right—there's a world of difference between 'checking torque' and 're-torqueing.' One simply observes, while the other actually gets the job done. Thanks for clearing that up!
Your statement of" high static torque of a stuck fastener" is a pretty fancy way of describing a simple, everyday problem that many shops face with improperly installed hardware or other issues like corrosion. But it's an impressive word choice for something so basic! But let's talk about that since you brought it up. During installation, the bolt generates tensile force(stretch) while encountering sliding friction(turn) as the head contacts the surface. However, when loosening the bolt, one must overcome static friction, which is inherently more significant than sliding friction due to its higher resistance before motion initiates—typically quantified as a percentage above the coefficient of sliding friction.
But when loosening a bolt, the torque required to loosen (versus breakaway), will be 70-80% lower than the original tightening torque, which leads people to think it was lose. But the real question is, why would you loosen an already properly tightened fastener just to retighten it, especially if you don’t have an accurate measurement of the initial torque? Without knowing the starting point, you're essentially guessing, which could lead to improper force or potential failure.
So, those who are looking for a baseline figure have two options.
Apply torque in the tightening direction to the bolt and note the value just before the bolt starts moving again. This helps estimate the initial torque without loosening the bolt entirely.
Or breakaway routine involves slowly applying torque to the fastener in the loosening direction until it just starts to move (breaks free). The value at which the bolt begins to turn gives you a rough estimate (really rough)of the installed torque. This method is commonly used in the field to determine how tightly the bolt was previously installed without having the known torque table.
I would only do the breakaway if I was removing the head and installing a new gasket.
In a perfect world, for any 961 that someone services, I would( and we have done this many times) disassemble the top end, replace the lifters, rockers, gaskets, and rings, and install better hardware, coat bolts as needed, if they want to minimize issues.
I am honestly lost as to what your beef is.
In answer to your question: Is it ok with me if you don’t re-torque your head gasket…? Frankly I have no interest or opinion!
Regarding 961s, Stu closed off the topic of 961 head bolts way back by simply stating that in his experience, there is never any binding, the bolts turn easily, and no backing off is required. At this point the case was closed with NO ONE being critical of anyone !
It was you sir, who brought up the topic after the fact, calling the whole practice of backing off as bullshit, calling people as lacking hands on experience, having no understanding, etc ! To answer your question, I’ve only had the one 961, but that’s irrelevant, this petty and unnecessary spat is only about whether or not backing off in general is BS or valid.
As you know, the reason for specifying a given torque on fasteners where the clamping forces between surfaces are critical, is to act as a proxy for those clamping forces (ideally we’d always measure stretch, but torque settings are just WAY easier).
Your baseline methods stated above are exactly what is common practice in automotive OEM assembly. But this is when everything is new, it’s highly inaccurate on old possibly corroded or stuck fasteners.
I think it’s important to agree here that we are not talking about checking fasteners to see if they’re coming loose, we are talking about checking if things have stretched and / or compressed and which could therefore impact on the clamping force.
Of course, you should always simply try tightening the fastener as you say, if it turns before the required torque you know it was loose, and torquing it up is straightforward. 100% agreed, nothing more is required.
But… if it does not turn, and when it is a fastener that’s suspect of some seizing… If you put a torque wrench on a stuck fastener to measure the torque, you are not measuring that proxy of the clamping force, you are measuring the ‘stuckness’.
In such a case, you could get the necessary torque reading, and believe it’s ok, when it may easily not be.
In this situation, the widely accepted method is to crack the fastener in reverse, then tighten it to the correct torque.
So in summary, 961 head bolts do not need backing off. Backing off as a general method, when appropriate, is not BS.
PS: I do think the Internet is great. I think folk will study it in the future and be amazed how two grown men, both very experienced in motorcycles and mechanical matters, from opposite sides of the planet, can argue about tightening bolts
