Post valve clearance problems...

[clevermetal]

the bolts won't change the bearing clearance at all, unless you're orders of magnitude out with the torque. The journals mate with the head on a flat, oil free surface, and the point at which the bolt exerts pressure is not over the bearing surface. The torque we're talking about here is not going to cause any measurable deformation in the cam journal.

The only thing increasing the torque is going to do is make it more resistant to vibration and possibly come loose earlier than intended (due to an increased creep rate).

[Jashdown]

So tell me why crank case bolts require correct torquing... The bearings in the cam are exactly the same as the bearings on the crank and big/little ends.

You aware that changing the clearance by fractions if a millimeter causes problems.

Engineers don't just pull numbers out of their ass for the torque values. oh well, it's not my bike so not my problem.

[clevermetal]

engineers don't pull numbers out of their ass, however

a. they only want to give a single number that's taken as the middle of the range of acceptable values
b. there's a very significant aspect of engineering called the safety factor of a design. i.e. how many times stronger it is than it needs to be. I wouldn't be surprised if a cam journal was atleast 2 or 3 times stronger than it needed to be, so torqueing it to 20Nm instead of 15Nm will cause an such an infintesimally small increase in deformation it really won't matter.

however, that being said, there's nothing wrong with doing it right, so if you do have a torque wrench why the hell not use it!

It's just I don't like the whole notion of how these engines, and engines in general, are so fragile. They are amazing and you can't hit shit with hammers but they're tougher than people realise.

[Jashdown]

It's not just the individual tightening, it's tightening all the bolts to the same spec. Otherwise some are tighter than others, so (on a greatly exaggerated scale) the cam shaft is more prone to shaking/wobbling/whatever you may call it. And when they are rotating up to 150 times a second, well I don't want to try it.

But they are actually quite fragile. You can completely ruin a crank case just by scraping a gasket surface wrong, or lunch an engine by being too careless and letting dirt get into an oil passage. Externally they are relatively tough, but internally, not so much.

[Aduro]

The bottom line here is if you don't use a torque wrench on engine internals your a dumbass and I do hope you never work on anothers vehicle with that mindset.

[Jashdown]

The RVF doesn't require a torque wrench for cam holder bolts, wew.

[clevermetal]

haha Aduro and your relatively aggressive comments

I think I've been misunderstood, and Jashdown you definitely can recover a scraped gasket surface, otherwise most 2 strokes wouldn't work because at some point some guy has pried the cases apart with a screwdriver because it wasn't going to come apart any other way.
That's what copper sealant is for!

Also you'd be amazed at the shavings of metal that come out with some engines' oil (older ducati's especially), but they still chug along quite happily.

I see what your saying with the cumulative effect of the different torque, interesting perspective, I hadn't thought of that. As you said, if the torque differences were huge it'd fuck it, but if you were a couple Nm out I still don't think it'll make a difference.

I'd also like to note that I do own a 1/4" torque wrench, and do use it

[Jashdown]

Haha a couple of NM would be negligible, most torque wrenches are out by nearly that much anyway. But when doing it by hand, each bolt is different and you will have different leverage for each one, so it's difficult to get them all the same. Unless you're Studricho and your arm is actually a correctly calibrated torque wrench..

I'm just OCD with that sort of shit, haha so no offense was intended in any way. My engine is my baby, so it gets treated as such.

[clevermetal]

Haha fair enough, I'll be sure to pay extra attention to any bikes you sell in the future

damn that studricho and his badassery..