Honda-SOHC

I've come back to this as it links into a question I was asked about the figures given for torque settings on manuals.

Question was "Why do the torque figures range over such a larger percentage difference given that some of the tolerancing is so very very fine and precise?" I couldn't answer this with credible logic.

Now,  if we apply it to these bolts only,  7 to 9lb per foot, has the top figure something in the order of 9 being 33% increase on the 7lb setting!

If you add in "marketer's" psychology of giving a price range,  the middle one being what you sell most of,  the lower figure to make the middle purchasers feel they've got something a little bit better for their informed choice,  and the highest cost,  is just pure additional margin for those foolish enough to shell out for it 

Comfortable we are in choosing the centre point,  and it just seems so logic doesn't it. So,  if you take the 8lb and work through possible errors/ potential for unquantified effects, you can get 8 + 10% torque wrench accuracy (depends which way it defaults) + 15% for grease/coppaslip change to torque measurements,  you can end up with 10.1lb measured torque.
Or for those making a decision that you should use the highest torque figure, something like 11.4lb 

It's easy to see why they are often stripped. Also why they gave us just screws on many of the covers on these engines so that generally people can't load too much torque onto them with just a screwdriver.

If you look at the joint on these cam covers,  they are metal to metal with no gasket to compress (once touching with the o-ring compressed) so have no yeald built into the torque interface.

If you had to specify it,  once the casting faces touch,  then you'd only need something like 2 to 3lb of torque to prevent the bolt backing out in use.  So a safety margin of double that, 6lb, would be a good set point to make sure they reliably exceeded a practical minimum during engine use.

Then if you set your torque wrench to 5lb,  lubricated the threads ONLY,  made sure the underside of the bolt head was clear of lubricant,  along with the casting face.  You should get a true torque of between 4.5lb (if torque wrench was 10%error in minus) to 6.3lb with all errors maximised to plus figures in above illustrations.

This would minimise potential of stripping them,  and make sure they don't  release in use.

As above,  not liked because they have very fine jets and air passages to get clean if not running. Some have pushed in jets too, making routine dismantling and cleaning harder than straight screw in types.

However, the jetting strategy is a better way to run an engine in pure, pedantic accuracy terms. They are referred to as lean burn,  but really they are more towards optimum fueling for constant running with accelerator pump facilitated extra fuel to accelerate when needed. 

"Conventional" carbs have to be run richer than ideal constantly to make sure they don't go too lean on snap throttle opening,  in effect the inverse of PD carbs.  Effectively running too rich under most light load conditions and resulting in more unburnt fuel passing through the engine.

It seems odd to say it,  but most advancement in engine oil condition has come from running jetting leaner so that less unburnt fuel is washed past the rings to dilute the oil.  It also impacts exhaust life too, with the liquid deposits containing significant acid concentration the more fuel is left unburnt. That should be of concern to those running new sets of four pipes on these bikes given the cost they are, along with limited mileage. None of the pipes being in any way protected from corrosion internally.

Sounds like a positive step towards optimum.

Longer running and more through heat range may see the plugs a bit better colour as it's used more.

Maybe it'll respond to airscrew tweak if not.

With a simple/static strobe gun you should see the timing moving as you rev it.  The advance mech should bring the timing mark earlier on the scale as you rev it. So you won't see it stay in the same place.

Non static guns have facility in which you can set the advance you expect to get at maximum,  then when you rev it it should show still at same F point.
The gun runs an offset to compensate for the desired advance,  if that makes sense.

I'm not familiar enough with the 400 engine to say that it's normal just from that picture,  you need another to compare as Julie says.

But my read of it is that it's the manufacturing process that needs to go through there to connect an internal gallery to the filter output route into the engine.

Looks like they've machined then plugged it to get in there that way. 

If left open,  it would just allow the oil to bypass the filter route on it way to the internal galleries. 

Without seeing the engine end of the cartridge filter it's difficult to be specific.

They work in the same way,  at least the filters I've seen, both original and cartridges flood the casing with oil,  force it through the filter material,  then exit via central port (screw thread or bolt)  into oil gallery of engines.

I thought the conversion just had a hollow male-to-male threaded stub to screw in place of Honda bolt that allowed the cartridges to be mounted to engine.  Sealing flange should be in same place.

Be interesting to see the photos when they arrive with you.

Yeh, I made a bit of a dog's dinner of that Steve.

Used the quote button on Julie's post and then deleted the text above the bit I wanted,  checked it with preview and it showed like it's now displayed,  but thought it would post correctly a bit like it doesn't show photos in preview.

Where have I gone wrong 

For the Velocette, it's great to have the bike you want and be able to ride out on it just when you feel like it.  I like seeing all the different bikes out at meets etc and be able to talk to the owners to find out more about them. A very nice bike.

On the book, I thought ultimately it was asking the question of should people be trained to pass the exams set for the subject ( purely theoretical)  or trained to do the job in a practical way that would enable the trainee to complete the tasks in real life situation.

The purely academic versus the vocational, or some mix of the two,  using the motorcycle, and running it correctly, as metaphor.